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EK-LA36-MM-001

July 1975

385 pages

Original

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Document:	LA36 DECwriter II Maintenance Manual
Order Number:	EK-LA36-MM
Revision:	001
Pages:	385
Original Filename:	http://bitsavers.org/pdf/dec/terminal/la36/EK-LA36-MM-001_LA36_DECwriter_II_Maintenance_Manual_Jul75.pdf

OCR Text

Digital Equipment Corporation
Maynard, Massachusetts

LA36 DECwriter II
MAINTENANCE MANUAL

EK·LA36·MM·001

LA36 DECwriter II
MAINTENANCE MANUAL

digital equipment corporation • maynard. massachusetts

1st Edition, June 1975

The material in this manual is for informational
purposes and is subject to change without notice.
Digital Equipment Corporation assumes no responsibility for any errors which may. appear in this
manual.
Printed in U.S.A.

The following are trademarks of Digital Equipment
Corporation, Maynard, Massachusetts:
DEC
FLIP CHIP
. DIGITAL

PDP
FOCAL
COMPUTER LAB

UNIBUS

6/76-14

CONTENTS
Page
CHAPTER 1

GENERAL DESCRIPTION

1.1
1.2
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.2.7
1.2.8
1.2.9
1.3
1.4
1.4.1

PHYSICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Character Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Bell Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Paper Feeding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Ribbon Drive System
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Carriage Servo System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Standard Current Loop Interface
. . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Optional Half-Duplex, (Active or Passive) Current Loop Interface . . . . . . . . . . . 1-11
Peripheral Interface Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
TECHNICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
OPTIONAL FEATURES AND ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . 1-12
EIA/CCITT Interface
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

CHAPTER 2

INSTALLATION

2.1
2.2
2.3
2.4
2.5

SITE CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SYSTEM CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UNPACKING AND INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INSTALLATION PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHECKOUT AND ACCEPTANCE PROCEDURES . . . . . . . . . . . . . . . . . . . . .

CHAPTER 3

OPERATION

3.1
3.2
3.2.1
3.2.2
3.2.3
3.3

OPERATOR CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
OPERATING PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-3
3-3
Loading Paper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Changing Ribbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-7
3-9
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,. 3-10

CHAPTER 4

THEORY

4.1
4.1.1
4.1.2
4.1.3
4.1.4
4.1.5
4.1.6
4.1.7
4.1.8
4.1.9
4.1.10
4.1.11
4.2
4.3
4.4

PROGRAM DESCRIPTION
4-1
Scratch Pad Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4·3
Initialization Routine (INIT) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-5
Position Routine (POSIT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-5
SERVO Routine
................................ .
4-8
SPEED Routine
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-8
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
INPUT Routine
BELL Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '. . . . . 4-12
PRINT Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
LINE FEED Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
LCV Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
NEXT Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
TIMING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
CONTROL LOGIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
KEYBOARD SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-22

iii

2-1
2-1
2-1
2-2
2-4

CONTENTS (Cont)
Page
4.5
4.5.1
4.5.2
4.6
4.7
4.8
4.9
4.9.1
4;9.2
4.9.3
4.9.4
4.10
4.11
4.12
4.13
4.14
4.14.1
4.14.2
4.14.3

DATA COMMUNICATIONS INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . 4·28
20 rnA Loop Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-28
20 rnA Loop Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-28
CLOCK LOGIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-28
UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER (UART) . . . . . . . . . . 4-33
CHARACTER BUFFER/GENERATOR AND PRINT HEAD SYSTEM . . . . . . . . . . . 4-33
CARRIAGE SERVO SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-37
Tachometer, Summing Network and Sum Amplifier . . . . . . . . . . . . . . . . . . 4-39
Encoder and Threshold Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-40
Encoder Signal Detector . . . . . . . . . . . . . . . . . . : . . . . . . . . . . . . . 4-40
Column Increment Counter and Carry/Borrow Generator . . . . . . . . . . . . . . . 4-40
BELL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42
liNE FEED STEPPER SYSTEM
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45
WAKE-UP CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45
POWER SUPPLY AND REGULATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45
PRINTER MECHANISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45
Carriage Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-47
Ribbon Feed Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-49
Paper Feed Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-50

CHAPTERS

ELECTRICAL SERVICING

5.1
5.1.1
5.1.1.1
5.1.1.2
5.1.1.3
5.1.1.4
5.1.1.5
5.1.1.6
5.1.2
. 5.1.2.1
5.1.2.2
5.1.3

ELECTRICAL TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off-Line Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Encoder Signal Processing Test . . . . . . . . . . . . . . . . . . . . . . . . . .
Servo Speed Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LF Stepping Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bell Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Printable Character Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clock Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On·Line Tests
Current Loop Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Serial Line Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-1
5-1
5·1
5·4
5-4
5-4
5-4
5·5
5·5
5·5
5·6
5·7

CHAPTER 6

MECHANICAL SERVICING

6.1
6.1.1
6.1.2
6.1.3
6.1.4
6.1.5
6.1.6
6.1.7
6.1.8
6.1.9
6.1.10
6.1.11
6.1.12

REMOVAL, REPLACEMENT, AND ADJUSTMENT PROCEDURES . . . . . . . . . . .. 6·1
Print Head Assembly . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. 6·1
Timing Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·3
LK02 Keyboard Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
LK03 Keyboard Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Printer Mechanism Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6·5
DC Motor and Encoder Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·7
Ribbon Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·9
Carriage Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·11
Ribbon Chassis Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·15
Idler Gear Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
Tractor Assembly (RH or LH) . . . . . . . . . . . . . . . . . . . '. . . . . . . . . . 6·17
Stepping Motor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·18

CONTENTS (Cont)
Page
6.1.13
6.1.14
6.1.15
6.1.16
6.1.17
6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
6.2.8
6.2.9
6.2.10
6.2.11
6.2.12
6.2.13
6.2.14
6.2.15
6.2.16
6.2.17
6.2.18
6.2.19

Logic Board Assembly (M7722)
Power Board Assembly
Fan Assembly
Transformer Assembly
Line Filter Assembly .
DISASSEMBLY , ASSEMBLY AND ADJUSTMENT PROCEDURES
Print Bar . . . . . . .
Tractor Drive Shaft
Tractor Support Shaft
Carriage Shaft(s) . . .
Carriage Plain Bushing
Tractor Drive Gear/Line Feed Clutch
Ribbon Drive Pulley . . . . .
Ribbon Drive Fafnir Bearing .
Ribbon Eccentric With Clutch
Backstop Spring . . . . . .
Ribbon Drive Rear Bearing ..
Ribbon Spool Friction Disks .
Ribbon Spool Ratchet Wheel(s)
Idler Gear
.....
Rear Door Bushing(s)
Cover Spring Clips
Carriage Alignment Tool Setup
Tractor Gap Adjustment
EIA (DF11-A) Interface

CHAPTER 7

ENGINEERING DRAWINGS

CHAPTER 8

ILLUSTRA TED PARTS BREAKDOWN

8.1
8.1.1
8.1.2
8.1.3
8.1.4
8.1.4.1
8.1.4.2
8.1.4.3
8.1.4.4
8.1.4.5
8.1.4.6
8.1.4.7
8.1.5
8.1.5 .1
8.1.5.2
8.1.5.3
8.1.5.4
8.2
8.3
8.4

HOW TO USE THE IPB
General . . . . . . . . .
Major Assembly Locator
Indented Parts Lists
Column Callout Description
Figure & Item
Description .
DEC Part No.
ECO Cut-In
Vendor Code/Part No.
Used On Code
Ref Fig No.
Symbol Usage . . . . . .
Hardware Designators
Attaching Hardware
(NFR) Not Field Repairable
Other Symbols
LA36 DECwriter II
LK02 KEYBOARD
LK03 KEYBOARD

· 6-19
· 6-20
6-20
· 6-21
· 6-22
· 6-22
· 6-22
· 6-26
6-27
6-28
6-32
6-36
6-36
6-37
6-38
· 6-40
· 6-42
· 6-44

· 6-45
· 6-47
· 6-47
· 6-48
· 6-48
6-48
· 6-48

8-1
8-1
8-1
8-1
8-1
8-1
8-1
8-1
8-1
8-1
8-2
8-2
8-2
8-2
8-2
8-2
8-2
8-3
· 8-33
· 8-41

CONTENTS (Cont)
Page
APPENDIX A

REFERENCE DATA

A.l
A.2
A.3

ABBREVIATIONS . . . . . . ..
SIGNAL GLOSSARY . . . . .
IC PIN LOCATION DRAWINGS

A-I
A-I
A-I

ILLUSTRATIONS
Figure No.

1-1
1-2
1-3

1-4
1-5
2·1
2-2
3-1
3-2
3-3
3-4
3-5
3-6
4-1
4-2
4-2a
4-3
4-3a

4-4
4-5
4-6

4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14

4-15
4-16
4-17
4-18
4-19
4-20
4-21
4-22
4-23
4-24

Tide
Outline Dimensions . . . . . . .
Functional Block Diagram . . . . . . . • . . . .
Current Loop Cable Connector Pin Designations
Standard Current Loop Interface
Optional Current Loop Configurations
Site Considerations . . . . .
Jumper Location Diagram
Operator Controls
Carriage Adjustment Lever
Paper Loading . . . . . .
Tractor Adjustment Knob
Paper Advance Knob '"
Ribbon Direction Changing Guide
Microprogram Flow Diagram
Initialize Routine
Start Routine for Initialize
Position Routine . . . . .
Start Routine for Position
Servo Routine
Speed Routine .
Input Routine
Bell Routine
Print Routine
Line Feed Routine
Last Character Visibility Routine
....... .
Next Routine
Control Logic Block Diagram
LK02 Keyboard Logic Diagram
Keyboard Timing Diagram "
Data Communications Interface Diagram
Data Communications Interface Timing Diagram
20 rnA Loop Receiver Diagram
20 rnA Loop Driver
Clock Logic
........ .
Clock Timing Relationship . .
UART/Mode Selection and Baud Rate Selection Logic
Character Buffer/Address Register/Generator and Print Head System
CG ROM Character Cell
Print Head Operation

Page
1-3
1-3
1-10
1-11
1-12

2-2
2-4
3-3

3-4
3-5
3·6
3-6

3-8
4-2
4-6
4-6

4-7
4-7
4-9
· 4-10
· 4-11
· 4-12
· 4-14
· 4-15
· . 4-17
· . 4-18
· . 4-20
· . 4-22
· 4-29
· 4-29
· 4·30
· 4-30
· 4-31
· 4-31
· 4-32
· 4·34
· 4-35
· 4-36
· 4-36

ILLUSTRATIONS (Cont)
Figure No.
4-25
4-26
4·27
4·28
4-29
4·30
4·31
4-32
4·33
4·34
4·35
4·36
4·37
4·38
4·39
5·1
5·2
5·3
5·4
5·5
5·6
5·7
5·8
5·9
5·10
5·11
5·12
5·13
5·14
5·15
5·16
5·17
5·18
5·19
5·20
5·21
5·22
5·23
5·24
5·25
5·26
5·27
5·28
5·29
5·30
5·31
5·32
5·33
5·34

Title
Carriage Servo System . . . . .
Tachometer Logic
. . . . .
Encoder and Threshold Detector
Encoder Signal Detector . . . .
Increment Detection Timing ..
Encoder Signal Detector and Column Increment Counter Timing Diagram
Column Increment Counter and CIB Generator Logic
Bell System Logic
Line Feed Stepper System .
Line Feed Timing Diagram .
Power Supply Block Diagram
LA36 Printing Principle
Carriage Subsystem
Ribbon Feed Subsystem
Paper Feed Subsystem .
Encoder +21 V Test Setup
Encoder -21 V Test Setup
+PTI and +PT2 Waveforms
+PTI and +PT2 Schmidt Waveforms
+INC and COUNT Flip·Flop Waveforms
COUNT Flip·Flop and COUNT Pulse Waveforms
COUNT Flip·Flop and CLR ± Flip·Flop Wavefonns
+INC and +TACH Waveforms
-PTI and -PT2 Waveforms
-PTI and -PT2 Schmidt Waveforms ..
-INC and COUNT Flip-Flop Waveforms
-INC and -TACH Waveforms . . . . .
- INC and 76 ps CLOCK Waveforms
-TACH Waveforms at QI2-B and Q12-C
-TACH and 76 ps Waveforms . . . . .
-TACH Waveform and SUM Waveform at JI-B
-TACH and MD Waveforms . . . . . . . . .
INC Wavefonn . . . . . . . . . . . . . . . .
COL INC COUNT 3 (MSB) and COL INC COUNT 2 Wavefonns
COL INC COUNT 3 (MSB) and BORROW H Waveforms
+INC and 76 /-IS Waveforms
..... .
+TACH and 76 /-IS Waveforms . . . . .
+TACH Wavefonns at Qll·B and QII-C
+TACH and SUM Waveforms
.... .
+TACH and MD Waveforms . . . . . .
COL INC COUNT 3 (MSB) and CARRY H Waveforms
LF Motor Phase 1 and Phase 2 Waveforms . . . . . .
LFI Waveform at TPA12 and LF2 Waveform at TPA15
LFI Wavefonn at TPA13 and LF2 Waveform at TPA16
LFI Waveform at TPA14 and LF2 Waveform at TPA17
LF Motor Common Return and LF HOLD Waveforms
LFI Waveform at JI-JJ and LF2 Waveform at JI-P
LFI Waveform at E24-9 and LF HOLD Waveform at E29·6
BELL Source and BELL SINK Waveforms . . . . . . . . .

vii

Page
· 4·37
· 4·39
· 4·41
· 4-41
· 4·42
· 4-43
· 4-44
· 4·44
· 4·46
· 4-46
· 4-47
· 4-48
· 4-48
· 4-49
· 4-50
5-3
5·3
5-9
5-9
· 5-10
· 5-10
5-11
· 5-11
· 5-12
· 5-12
· 5-13
· 5·13
5·15
· 5-15
· 5·16
· 5-16
· 5-17
· 5-17
· 5·18
5-18
· 5-19
· 5·19
· 5·20
5-20
· 5-21
· 5·21
· 5-23
· 5-23
· 5-24
· 5-24
· 5·25
· 5-25
· 5-26
· 5·27

ILLUSTRATIONS (Cont)
Figure No.
5·35
5·36
5·37
5·38
5·39
5-40
5-41
5-42
5-43
5-44

5-45
5-46
5-47
5-48
5-49
5·50
5·51
5·52
5·53
5·54
5·55
5·56
5·57
5·58
5·59
5·60
5·61
5·62
5·63
6·1
6-2
6-3
6-4
6-5
6-6
6·7
6-8
6·9
6-10

6-11
6-12
6-13
6-14
6-15
6·16
6·17
.6·18
6-19
6-20

Tide

Page

BELL SINK and BEL Waveforms
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5·27
KBH H Pulse Waveform
. . . . . . . . . . . . .
. . . . . . . . . . . . . 5·28
HD EN and SOL Waveforms at J6
. . . . . . . . . . .
. . . . . . . . . . . • . 5·29
HSI and SDI Waveforms at TPP
. . . . . . . . . . . . .
. . . . . . . . . . . . . 5·29
. . . . . . . . • . . . .
. .; . . . . . . . . . . . 5·30
HSI and SDI Waveforms at TPN
HSI and SDI Waveforms at TPL . • . . . . . . . . . . . . .
. . . . . . . . . . . . . 5·30
HSI and SDI Waveforms at TPM
. . . . . . . . . . . . . . . . . . . . . . . . • . . . . . 5·31
HD EN and HS7 Waveforms at Jl (R35) . . . . . . . . . . .
. . . . . . . .
. . 5·31
HD EN and HS6 Waveforms at Jl (R15) . . . . . . . . . . .
. . . . . .
. . . . 5·32
HD EN and BUFF HEAD EN H Waveforms . . . . . . . . .
. . . . . . . . . . . . . 5·32
HD EN Voltage Waveform and SD Current Waveform . . . .
. . . . . . . . . . . . . 5·33
WRITE BUFF Land CLR R DONE Waveforms . . . . . . . . . . . . . . . . . . . . . . . 5·33
KEY STB L Waveform . . . . . . . . . . . . . . . . . . . .
.• .
. . . • . 5·34
CLK Hand 592 ns Waveforms . . . . . . . . . . . . . . . . . . . . . .
. . . . . 5·35
592 ns and 1.184 ps Waveforms
. . . . .
. . . . . . . . . . . .
. . 5·35
76 ps and 9.4 ps Waveforms . . . . . . . . . . . . . . .
. . . . . .. . 5·36
19 Land 9.4 ps Waveforms
. . . . . . . . . . . . . . .
. . . . . . .. . 5·36
76 ps and 18.8 ps Waveforms
. . . . . . . . . . . . . . .
. . . . . . .. . 5·37
4.8 kHz and 18.8 ps Waveforms
. . . . . . . . . . . . . . .
. . . . .. . 5·37
208 Hand 4.8 kHz Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5·38
1.76 kHz and 37.6 ps Waveforms
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5·38
. . . . . . . . . . . . . . . . 5·39
Current Loop Test Setup . . . .. . . . . . . . . . .
Loop Receiver Waveforms . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . 5-40
Loop Driver Waveforms . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . 5-40
Serial Line Test Setup . . . . . . . . . . . .
. . . . . . . . . . . . . . . . 5-41
. . . . . . . . . . 5-41
Serial Output and Serial Input Waveforms ..
; .
. . . . . . . . .. .. 5·60
Typical Voltages for Power Supply Regulators
Typical Voltages for VRef Supply . . . . . .
. . . . .
. . 5·61
. . . . .
. .. 5·61
Print Head Solenoid Resistance Measurement
Housing Removal
..............
. . . . .
. . . 6-49
Power Board Connectors .. . . . . . . . . .
. . . . .
. . . 6·50
Ribbon Cable Clamps . . . . . .
. . . . . .
. . . . . . . . . . . . . . . . 6·51
. . . . . . . .
. . . . . . . . . . . . . . . . 6~52
Print Head Removal
Carriage Adjustment Lever . . . . . . . . . . . . . . .
. . . . . . . . . . . . 6·53
Print Head Adjustment . . . . . . . . . . . . . . . . .
. . . . . . . . 6·54
Ribbon Threading/Drag Test . . . . . . . . . . . . .
. . . . . . . 6·55
Timing Belt Removal . .
. . . . . . . . . . . . .
. ...
. . . . . . . . 6·56
Keyboard Bezel Removal
. . . . . . . . '.' . . .
. 6·57
LK02 Keyboard Removal
. . . . . . . . . .
. . . . . . . . . . . . 6·58
LK03 Keyboard Removal
. . . . . . . . . . . . .
. . . . . . . . . . . . . 6·59
Power Board Connectors
. . . . . . . . .. . . . . .
. . . . . . . . . . . . . 6·60
Printer Mechanism Removal
...... . . . . . . . .
. . . . . . . . . . . . . 6·61
Printer Mechanism Alignment . . . . . . • . . . . . . .
.. . . . . .. . . . . . . . 6·62
Printer Mechanism Adjustment
. . . . . . . . . . . .
. . ... . .. .. 6·63
DC Motor Removal
............ . • . .
. . . . . . . . . . 6·64
PTI or PT2 Waveform . . . . . . . . . . . . . . .
. . . . . . . . . . 6·64
Encoder (Rear View) . .
. . . . . . . . .
. . . . . . . 6·65
Encoder Jitter . . . . .
. . . . . . . . . . . . •
. . . 6-65
PTl and PT2 Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·66

viii

ILLUSTRATIONS (Cont)
Figure No.
6-21
6-22
6-23
6-24
6-25
6-26
6-27
6-28
6-29
6-30
6-31
6-32
6-33
6-34
6-35
6-36
6-37
6-38
6-39
6-40
6-41
642
6-43

644
645
646
6-47
6-48
6-49
6-50
6-51
6-52
6-53
8-1
8-2
8-3
8-4
8-5
8-6
8-7

8-8
8-9
8-10
8-11
8-12

8-13
8-14
8-15
8-16

Title
Ribbon Drive Removal . .
Ribbon Drive Adjustment
Carriage Removal
Print Bar Alignment/Parallelism
Ribbon Chassis Removal .
Ribbon Drive Adjustment
Idler Gear Removal
Tractor Removal . . . . .
Tractor Phasing! Adjustment
Stepping Motor Connector (J5)
Stepping Motor Removal
Logic Board Removal
Power Board Removal
Fan Removal . . . .
Transformer Removal
Capacitor C5 . . .
Rocker Switch Sl
Print Bar Removal
tractor Drive Shaft Removal
Line Feed Clutch/Knob Removal
Tractor Support Shaft Removal
Carriage Shaft Removal
Tractor Drive Gear Removal ..
Ribbon Drive Pulley Removal
Ribbon Drive Pulley Adjustment
Fafnir Bearing Removal
Ribbon Drive Shaft Adjustment
Friction Disk/Ratchet Wheel Replacement
Rear Door Bushing Replacement
Cover Spring Clips . . . . . .
Carriage Alignment Tool Setup
Tractor Gap Adjustment .
EIA (DF11-A) Interface
LA36 DECwriter Assembly
Cabinet Assembly (With Power Supply)
Power Board Assembly (LA36) Etch Rev. B
Logic Board Assembly (M7722) Etch Rev. C
Printer Mechanism Assembly
Ribbon Drive Assembly
Ribbon Chassis Assembly
Carriage Assembly
Idler Gear Assembly
Transformer Assembly .
Keyboard Bezel Assembly
Keyboard Bezel Assembly (With Numeric Pad)
Capacitor Harness Assembly . . .
Cable Assembly (LA36 Keyboard)
Cable Assembly (BC05F Interface)
LK02 Keyboard Assembly . . . .

Page
6-66
6-67
6-68
6-69
6-70
6-71
6-72
6-73
6-74
6-75
6-76
6-77
· 6-78
· 6-79
· 6-80
_ 6-81
6-82
6-83
6-84
6-85
· 6-86
6-87
6-88
6-89
6-90
6-91
· 6-92
· 6-93
6-94
6-95
6-95
6-96
6-97
84
8-7
8-9

8-13
8-17
8-20
8-22
8-24
· 8-25
8-26
8-27
8-28
8-29
8-30
8-31
· 8-34

ILLUSTRAnONS (Cont)
Figure No.
8-17
8·18
8·19
8·20
8·21
A·1
A·2
A·3

A4
A·5
A·6
A~7

A-8
A·9
A·10

A·ll
A·12
A·13
A·14
A·15
A·16
A·17
A·18
A·19
A·20
A·21
A·22
A·23
A·24
A·25
A·26
A·27
A·28
A·29

Title

Page

LK02 Keybo,ard Module (Etch Rev. D)
. . . . . . . . . . . . .
· . . . . . . 8·37
Keyswitch Array Assembly
................... .
· . . . . . . 8·38
LK03 Keyboard Assembly . . . . . . . . . . . . . . . . . . . . . .
· . . . . . . 842
Keyswitch Array Module (Etch Rev. B) . . . . . . . . . . . . . . . . . . . . · . . . . . . 843
Keyswitch Array Assembly
...................... .
· . . . . . 844
380 Quad 2·Input NOR Gate
..................... .
· . . . . A·13
1702A 8·Bit Reprogrammable ROM . . . . . . . . . . . . . . . . . . .
· . . .. A·13
2627P A6-01 Character Generator Alpha . . . . . . . . . . . . . . . .
A·14
3101 Random Access Memory . . . . . . • . . . . . . . . . . . . . . .
A·15
7400 Quad 2.Input Positive NAND Gate . . . . . . . . . . . . . . . . .
A·16
7401 NAND Gate·Quad 2·Pin Open Collector . . . . . . . . . . . . . . . . . . ..
A·16
7404 Hex Inverter . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . • . . . A·16
7408 Quad2·Input Positive AND Gate
. . . . . . . . . . . . . .
. . . . . . A·I7
7410 Triple 3·Input Positive NAND Gate
. . . . . . .
. . . . . . A·17
. . . . . . .
. . • . . . . . . A·I8
7413 Schmidt Trigger . . . . . . .
. . . . . . .
. . . . . . A·18
7416 Hex Inverter Buffer/Driver . . . .
7417 Hex Buffers/Drivers . . . . . . . . . . . • . . . . . . .
. . . . . . . . . A·19
7420 NAND Gate·Dual4·Input . . . . . . . . . . . . . . . . . . . . .
.. . . . . . A·19
7423 . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . A·20
7437 NAND Gate·Quad 2 In Buffer, 14 Pin . . . . . . . . . . . . . . . . . . . . . . . . A·20
7442 4·Line·to·IO·Line Decoders
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . A·21
. . . . . . .
. ... .
7474 Dual D·Type Edge·Triggered Flip·Flop . . . . . .
A·22
7489 64·Bit Read/Write Memory
.................
. ... .
A·22
7493A Counter Asynch Up, Binary . . . . . . . . . . . . . . . . . . .
. . . . .
A·22
74123 Monostable Multivibrator .. . . . . . . . . . . . . . . . . . . ..
. ... .
A·23
74150 Data Selector/Multiplexer
........................... .
A·23
74154 4·Line·to·26·Line Decoder/Demultiplexer . . . . . . . . . . . . . . . . . . . . . A·24
74161 4·Bit Binary Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A·24
74175 Quad D·Type Flip·Flop with Clear . . . . . . . . . .
. ... .
A·25
74190 Counter, Synch Up/Down Decade, 16 Pin . . . . . . . . . . . . . . . . . . . . . A·26
. . . . . . . . . A·27
74193 Synchronous 4·Bit Up/Down Counter . . . . .
Universal Asynchronous Receiver Transmitter . . . . . . . . . . . . . . . . . . . . . . . A·28
301 AN DIP Operational Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . A·28
309 K Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A·29

TABLES
Table No.
1·1
1·2
1·3
14
1·5
1·6
1·7
1·8
2·1

Title

Page

Standard ASCII Character Set and Code .
. . . . . . .. 1·2
ASCII Codes and Responses . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . 1·5
Standard Full·l)uplex 20 rnA Current Loop Cable Connections . . . . . . . . . . . . . . . 1·10
Optional Half·Duplex 20 rnA Current Loop Cable Connections . . . . . . . . . . . . . . . 1·11
. . . . .
. . . . . . . . . . . . . . . . . . . . . 1·13
Interface Port Connector Pins
Technical Characteristics . . . . . . . .
1·13
Interface Specifications . . . . . . . . . . .
1·16
EIA/CCITT Interface Connector Pins
1·17
Parity Configuration Jumpers . . . . . . . .
2·3

TABLES (Cont)
Table No.

2-2
3-1
3-2

4-1
4-2
4-3
4-4
4-5
4-6

4-7
5-1
5-2
5-3

A-I
A-2

Title

Page

Current Loop Configuration Jumpers
................. .
2-5
3-1
Control and Function Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operator Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .
3-9
Scratch Pad Allocations . . . . . .
. . . . . . . . . . . . . . . . . . .
4-4
SPEED Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-9
Keyboard ROM Addressing
. . . . . . . . . . . . . . . . . . .
.. 4-23
. . . . 4-32
Clock Frequencies and Time Periods . . . • . . . . . . . . . . . . . . . . .
Baud Rate Switch Connections . . . . • • . . . . . . . . . . . . . . . . .
· .. 4-34
MPC SPEED Command Truth Table . . . . . . . . . .
. . . . . .
· .. 4-38
LF Pulse Truth Table . . . . . .
· .• 4-47
test Equipment and Special Tools
. . . . . . . . ..
· . . . . . .. 5-2
Troubleshooting Chart . . . . . . . . . . . . . . . .
· • . . • • • . 5-43
· '. . . . . . . 5-59
OC Supply Voltages . . . . . . . . . . . . . . . . .
Glossary of Abbreviations
. . . . . . . . . . . .
• . • . . . • • A-3
Signal Glossary . . . . . . . . . . . . . . . . . . . . . . . .
· . . . . . . . A-7

7037 -14

LA36 DECwriter II

CHAPTER 1
GENERAL DESCRIPTION

The LA36 DECwriter II is a small, low cost printer that can be used both as a remote terminal and a local computer
I/O device. A true 30-character per second throughput is provided for full utilization of a 300 baud communications
line without the use of fill characters. Data can be sent or received in standard ASCII code at 3 rates: 110,150 and
300 baud.
The printer produces a hard copy original plus up to 5 duplicate copies on tractor-driven continuous forms varying
in width from 3 to 14-7/8 inches. Preprinted forms can be positioned in exact vertical alignment by operating a
manual clutch on the tractor drive. The standard set of 96 upper and lower case ASCII characters (Table 1-1) is
printed at a horizontal spacing of 10 characters per inch and a vertical spacing of 6 lines per inch. A switch on the
keyboard printed circuit board allows selection of a reduced set of 64 upper case ASCII characters.
NOTE
On machines with serial numbers below 15700, this switch is
internal. On units above 15700, this switch is accessible to an
operator and is called "Keyboard Caps Lock Key."

1.1 PHYSICAL CHARACTERISTICS
The unit is a free-standing, pedestal-type terminal. Dimensions are shown in Figure 1-1. There are two major
mechanical assemblies and three circuit boards in the unit. Mechanical assemblies are: Printer Mechanism and Print
Head, which are mounted on a cabinet base. A complete mechanical breakdown of the LA36 is prOVided in Chapter
8.
Electronic components are mounted on a Keyboard Assembly, Logic Board, a Power Board and an EIA module for
units operating in the EIA mode. The Logic Board, which contains all logic control function parts, is mounted on
the rear door of the cabinet to simplify access during maintenance. The Power Board, which contains all power
amplifier, driver, and dc power supply and regulator parts, is mounted against the rear wall of the cabinet. Large
components, such as the power transformer, EIA module, and filter capacitors are mounted on the base of the
cabinet. The line cord enters at the base of the cabinet. A fan mounted inside the cabinet provides forced-air cooling.
Low-voltage, high-energy terminals are protected against accidental shorts by fuses.
1.2 FUNCTIONAL DESCRIPTION
A functional block diagram is shown in Figure 1-2. The LA36 prints by moving a 7-wire print head horizontally
along the print line, firing the individual wires at the appropriate times to produce a 7 X 7 dot matrix character.
The print head travels on a carriage system and is connected to the drive system by a timing belt. A reversible dc
servo motor provides the drive power for the print head and for the ribbon drive mechanism. An encoder on the
motor produces feedback pulses that are used by the logic to keep track of the print head position.

1-1

Table 1-1
Standard ASCII Character Set and Code
0

COL2 COLa

10
I

I
I

121

COLU COLS' COI.6 COL7

0 m p \ F'
.I :I. A G1 (:$ (j
II
.I:).. E{ r'.... J:.l 1\
.-;(
:11: .. r ...(::.J C.. '::~
•• J
'=f: ·4 D T 1•• 1 t
% J'"..:) r'... u (~ 1..1
SP

' )

B4 B3 B2 BI

0 0 0

0 0

1 0

r'.. 'v' '1'" V

13 0 0

0 0

"or

+ y I,{ r.. II.. -{

.'"..' I... \ :I.

I
I

0 0

III

}

..'

M J

1"1

1 0

"ii.

()

DEL

(,.\

'..1

-::$ W
7 13 1..•..1 ...•
\/
<:('5 H 1\ j"'1 .. '.
.
f) I Y :1. '.J
.
.,.
....I Z
.:... -..) .....'

(

)

*
,..

....

-•• 1

.. I

.t.

.....

,...
....

1·2

!frO>

III"

------..,

( 33. 5")

(852 mm)

L24.0"~

L25.0"---.J

(610mm)

(635mm)
CP-1571

Figure 1·1 Outline Dimensions

SET/CLR BEL
BELL
SYSTEM

2.4KHz

CRYSTAL
CLOCK

1.6B96MHz

LINE FEED
STEPPER
SYSTEM

LF/LF HOLD

MICROPROGRAMMED
CONTROLLER

CARRY/BORROW INCREMENT

IMPC)

SPEED DATA ~

DATA BUS

CHARACTER
ADDRESS
DATA
COMMUNICATIONS
INTERFACE
SERIAL
INPUT

J
I

SERIAL
OUTPUT

RECEIVE
LOOP
TRANSMIT
LOOP

<=-

D
A
T
A
B

I
I
I

~--~

RI880N
DRIVE
SYSTEM

ADDRESS REGISTER
UA RT
CHARACTER BUFFER

I
CARRIAGE
SERVO
SYSTEM

I
I

'ooT.,~

PRINT HEAD
SYSTEM

CG ROM

ill

STROBE

COLUMN INCREMENT COUNT

KEYBOARD
SYSTEM
CP-1378

Figure 1·2 Functional Block Diagram

1·3

Line feeding is accomplished by a pin-feed tractor system that is driven by a stepping motor through a simple gear
mechanism.
A Microprogrammed Controller (MPC) is used to control the printer.
1.2.1 Character Printing
At power up, the print head is moved slowly to the left until it hits the end stop. This point is used as a reference by
the MPC to determine the location of the printed line. The first print column is set about 0.15 in. to the right of the
end stop.
Incoming characters from the Keyboard System or the Data Communications Interface are placed in a 16 character
read/write FIFO (First-In, First-Out) buffer. Under normal operation, the buffer will never overflow; however, in
case of overflow, the most recently received character is lost.
Detection of printable characters and decoding of control characters is performed by the MPC based on information
stored in the Character Generation ROM (Read Only Memory). This allows the implementation of arbitrary
character sets simply by changing the ROM.
In the standard ASCII character set, there are 95 character codes which are interpreted as printable. For each of
these characters, the Carriage Servo System is commanded to move through one character cell. The print head
solenoids are energized each 0.01 in. of motion to form the 7 columns of the 7 X 7 dot matrix for the character. The
96th character code (DELETE) is a nonprinting, nonspacing control code.
Four additional codes are interpreted by the MPC: Carriage Return (CR), Line Feed (LF), Backspace (BS) and Bell
(BEL). The remaining 28 ASCII codes are nonprinting, nonspacing control codes that cause no operation in the
printer.
Carriage return and backspace operations are described in Section 1.2.5. Line feed operation is described in Section
1.2.3.
Table 1-2 identifies the 7-bit ASCII codes generated by the LA36 keys and the responses of the LA36 to all
incoming codes.
1.2.2 Bell Operation
Receipt of the Bell character causes an audible tone to be produced. A separate tone burst is produced from each of
up to eight bell codes received in succession.
If the keyboard has been activ.e during the printing of a line, the audible tone is generated when the carriage passes
the 64th character position.
1.2.3 Paper Feeding
The LA36 is designed for pin-feed paper up to 14.875 in. wide. The hole spacing along the edge is 0.500 in.
± 0.010 in. (non-accumulative over 2,0 in.) with a hole diameter of 0.150 in. to 0.160 in. Multi-part forms of up to

six sheets (and five carbon sheets) may be used, with a maximum allowable total thickness of 0.020 in. (measured at
about 20 psi pressure). Card stock of one layer may be used, with a maximum thickness of 0.007 in. Multi-part
forms may have only one card part; the card must be the last part. A print head gap control (Figure 3-1) is provided
for the operator to adjust for the thickness of various forms, which range from 0.003 in. to 0.020 in.

Table 1-2
ASCII Codes and Responses
KEYBOARD OPERATIONS
To Transmit, Type Keyls)
ASCII Code

RECEIVE O~ERATIONS

Character

SHIFT*

CTRL*

CHAR

Character
Printed

V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V

SPACE

None

000

NUL

001

SOH

002

STX

003

ETX

004

EOT

005

ENO

006

ACK

007

BEL

010

011

012

013

014

015

016

017

020

OLE

021

DC1

022

DC2

B
C
D
E
F

None

BELL

Sound Alarm Bell

None

VT
FF

None
Move print head to left margin

None

0
P

v'
v'

V
V

025

NAK

026

SYN

027

ETB

030

CAN

v'
v'

031

032

SUB

033

ESC

034

035

036

V
V
V
V
V
V
V

Advance Paper one line

DC3

None

DC4

040

Backspace one position

024

037

None

023

Action/Description

[

DELETE

None

space bar

Blank Space

None
Print character. move print head
one position to the right.

*A check in this column indicates the key (SHIFT or CTRL) that must be held down while the character key is typed.
If both keys are checked. then both keys must be held down.

1-5

Table 1-2 (Cont)
ASCII Codes and Responses

KEYBOARD OPERATIONS
To Transmit, Type Key(s)
ASCII Code

Character

SHIFT*

041
042

..;
..;

043
044
045
046
047
050

#
$
%
&

,
(

051

)

052

053
054

..;
..;
..;
..;

CHAR

Character
Printed

"
#

&
,

..;
..;
..;
..;

..;

055
056
057

CTRL*

RECEIVE OPERATIONS

(

)

/
0
1
2
3
4
5
6
7

065
066
067

5
6
7

/
0
1
2
3
4
5
6
7

070
071

072
073
074

;

060
061
062
063
064

0
1
2
3
4

..;

;

..;

075
076

077

100

101

102

103

104

..;
..;
..;
..;
..;
..;
..;

Action/Description
Print character, move print head
one position to the right .

Print character, move print head
one position to the right.

*A check in this column indicates the key (SHIFT or CTRL) that must be held down while the character key is typed.
If both keys are checked, then both keys must be held down.

1-6

Table 1·2 (Cont)
ASCII Codes and Responses
KEYBOARD OPERATIONS
To Transmit, Type Key(s)
ASCII Code

Character

SHIFT*

105
106
107
110
111
112
113
114
115
116
117
120

V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V

121
122
123
124
125
126
127
130
131
132
133
134
135
136
137
140
141
142
143
144
145
146
147
150

F
G
H

I
J

K
L
M

N
0

a
R

S
T
U

V
W

X
Y

CTRL*

..;

RECEIVE OPERATIONS

CHAR

Character
Printed

[

V
..;

Action/Description
Print character, move print head
one position to the right.

,
Print character, move print head
one position to the right.

* A check in this column indicates the key ISH I FT or eTR L) that must be held down while the character key is typed.

If both keys are checked, then both keys must be held down.

1·7

Table 1-2 (Cont)
ASCII Codes and Responses
KEYBOARD OPERATIONS
To Transmit, Type Key(s)

RECEIVE OPERATIONS·

CHAR

Character
Printed

152

153

ASCII Code

Character

151

SHIFT*

CTRL*

154

155

156
157

160

161

162

163

164

165

166

167

170

171

172

173

174

I
I

175

\
I

176

177

DEL

V
V
V

Action/Description
Print character, move print head
one position to the right.

DELETE

None

t"nnt cnaracter, move pnnt neaa
one position to the right.
None

• A check in this column indicates the key (SHI FT or CTRL) that must be held down while the character key is typed.
If both keys are checked, then both keys must be held down.

A full II-in. high box of paper may be placed under the rear of the printer stand. The paper is fed through a slot
under the mechanism. Loading can be facilitated by opening the head gap to maximum with the printer cover open.
Special attention should then be given to readjusting the head gap to the corresponding paper thickness setting as
directed in Chapter 3,Section 3.2.1. The feed holes of the paper are engaged by two tractors of 11 pins each after
passing through the print station. Supports are provided for the incoming and outgoing paper to prevent
interference.
The drive tractors may be adjusted horizontally to register properly with any form with hole spacing in the
casework, and are provided with a knob for manual paper advance. The shaft is driven through a reduction gear by a
stepper motor. Each line feed operation advances the paper 1/6 in. This is performed in 33 ms maximum, either
singly or in succession. Consequently, paper feed rate is 5 inches (or 30 lines) per second.

1-8

1.2.4 Ribbon Drive System
A 40-yard, 0.5-in. wide ribbon is wound upon two 3-1/4 in. diameter spools. Two rivets are provided in the ribbon,
one near each end, to serve as a reversing tripper.
Power from the carriage drive motor moves the ribbon through a drive belt and a one-way clutch and a reversing
mechanism. The clockwise motion of the motor during printing is used to drive the ribbon; no ribbon motion occurs
during carriage return. The drive is a/ways connected to one of the two spools. The connecting mechanisms are
controlled by a power shift which is triggered by the reversing sensors. As one spool empties, the rivet on the ribbon
pushes a lever into the path of a shift tab which flips the ratchet from one reel to the other. Ribbon tension of 3 oz.
is maintained by drags composed of spring-loaded disk brakes on each spool hub.
1.2.5 Carriage Servo System
The Carriage Servo System is a dc servo mechanism that contains a power amplifier driving a conventional
pennanent-magnet dc motor which drives the carriage through a timing belt. The movement of the motor shaft and
hence the position of the carriage is detected by an optical incremental encoder which produces one pulse for each
0.01 in. of carriage motion.
A one-decade, up/down BCD (Binary Coded Decimal) counter keeps track of the carriage position within a character
space. The overflow of this counter is monitored by a MPC and is used to determine the carriage position and for
other control functions. The speed of the motor during printing, carriage return, and LCV (Last Character Visibility)
is controlled by the MPC by means of a register which in tum controls the output voltage of the power amplifier
feeding the motor.
Printing is accomplished by moving the print head from left to right across the space to be occupied by the
character. When a BCD counter indicates that the carriage is at a given dot position, the appropriate solenoids are
energized to print. If the carriage is to the right of the starting position for the character, the carriage is moved to the
left of the starting position before printing commences. If there is a second printing character in storage while a
character is being printed, the carriage speed is increased to catch up. When printing is complete, the carriage stops.
When a backspace character is received, the carriage is moved to the left a distance of one character cell (0.1 in.).
This function allows character overprinting without an intervening carriage return.
When a carriage return character is received, the carriage is moved to the left-hand margin. Carriage speed is a
function of the distance between the carriage and the left-hand margin. The time required to return the carriage to
the margin is compensated for by an accelerated print rate until no more than one character is in the buffer.
When approximately two seconds have elapsed without a printable character input, the carriage moves four character
spaces to the right to pennit the operator to see the last character. When printing is to be resumed, the carriage
moves to the left to begin printing.
1.2.6 Power Supply
The main power supply is an unregulated supply with nominal output voltages of +21 Vdc and -21 Vdc. The
minimum instantaneous output voltage is 15 V for full load and minimum line voltage.
The 5 V supply for the logic has a regulation of ±5% with 200 m V pop maximum ripple.
Regulated voltages of +12 V ±5% and -12 V ±5%, with 500 mV Pop maximum ripple are provided for operational
amplifier and MOS (Metal Oxide Semiconductor) circuits. A -9 Vdc regulator is included on the Logic Board when
the PROM (Programmable Read Only Memory) option is supplied.

1-9

1.2.7 Standard Current Loop Interlace
The stand~;d interface is a full·duplex, passive 20 rnA current loop similar to a Teletype@ interface. The cable pin
connections are shown in Table 1-3 and Figure 1-3. (Polarities denote current flow.) Circuit operation is shown in
Figure 1-4. (polarities denote current flow.)

Table 1-3
Standard Full-Duplex
20 rnA Current Loop Cable Connections
Connector Pin Numbers
To Logic Board
Connector J3

Circuit

Description

Transmit (+)
(keyboard)

Negative side
of line

Transmit (-)
(keyboard)

Positive side
of line

Receive (+)
(printer)

Negative side
of line

Receive (-)
(printer)

Positive side
of line

To Host Computer
Connector

PI-2

U-~

P2-3

Pl-S

P2-7

PI-3

P2-2

PI-7

~I'¥'

P2-S

G-

wl-\
,

Typing each specific key causes the LA36 transmitter switch to be opened and closed in a pattern that defines the
key.
The 20 rnA communications circuit will operate wherever the current source is located. A device is said to be active
if it supplies the current for the communications loop and passive if it receives current from another device.
The LA36 is shipped with a 20 rnA cable (BCOSF) to interface the terminal as a passive device to a computer, or to
another peripheral device that is operating as an active device.

8
CP-1I65

Figure 1-3 Current Loop Cable Connector Pin Designations

®r'eletype is a registered trademark of Teletype Corporation.

1-10

LA36

HOST (COMPUTER)
ACTIVE TRANSMITTER

PASSIVE RECEIVER

CURRENT
SOURCE

XMIT

INTERFACE
CABLES
UP TO
7

~>-

20 MA
LOOP
RCVR

;~5..2<2..~~

1 - - - - -......-

- --~ :3

TO
PRINTER

I SEE

______ J NOTE

TRANSMITTED
DATA

PASSIVE TRANSMITTER

ACTIVE RECEIVER
RECEIVED

DATA~- -

20MA
LOOP

REC

1-----1 ~>- - r----i~>--

REC

_X_M_T_R~_ _ FROM

~>
~>-

KEYBOARD

CURRENT
SOURCE

CP-t167

NOTE: Loop switches are tronistorll.

Figure 1-4 Standard Current Loop Interface
1.2.8 Optional Half-Duplex, (Active or Passive) Current Loop Interface
In the half-duplex mode, transmission between two devices can take place in only one direction at a time; however,
no keyboard lockout is provided. Any of the configurations shown in Figure 1-5 can be obtained by using jumpers
on LA36 Logic Boards; the jumpers can be changed as described in Chapter 2 Section 2.s.4~ The configurations on
the left of the diagram show the LA36 used as an active device, I'roviding its own current source; the configurations
on the right show it being used in the half-duplex mode, both as a passive and an active device.

Cable pin connections are shown in Table 1-4.

Table 1-4
Optional Half-Duplex
20 rnA Current Loop Cable Connections
Connector Pin Numbers
To Logic Board
Connector 13

To Host Computer
Connector

Pl-s

P2-3

Pl-3

P2-S

1-11

Circuit

Description

Transmit (+)
~keyboard)

Negative side
of line

Receive (-)
(printer)

Positive side
of line

HALF DUPLEX
(PASSIVE)
ACTIVE TRANSMIT

RECEIVE DATA r----'---,
TO PRINTER

~}+TO

PASSIVE
JXMIT- RECEIVER

XMIT DATA

~"C: !E!.~D- ~:'J

XMIT DATA
FROM KEYBOARD

• }TO
ACTIVE HALF

~,-~_E_E_N_O_T_E_-Ir DU",,, PORT

NOH

t
HALF DUPLEX
(ACTIVE)

ACTIVE RECEIVE

r---~VII\.,,---.,

,....--~'M....- - . . ,

b+)
REC-

TO PASSIVE
TRANSMITTER

Lt-.} ~gSSIVE
-

HALF
DUPLEX PORT

RECEIVE DATA
TO PRINTER

RECEIVE DATA ,....---1.---,
TO PRINTER

XMIT DATA
FROM KEYBOARD,

""_J-J SEE NOT E

. - - - - - ' ' M...._ _

NOTE: Loop switches are transistors.

CP-1164

Figure 1-5 Optional Current Loop Configurations
The active connection defeats the isolation of signal line and local circuits, requiring that appropriate protective
measures, such as high potential breakdown grounds (lighting arrestors, etc.) be installed on the signal line and that
care be taken to ensure that protective (frame) ground is connected.
1.2.9 Peripheral Interface Port
The LA36 has a connector for non-current loop interfaces. The connection is via a straight 8-pin Mate-N-Lok
connector, J4, with the pin designations listed in Table 1-5.
The interface using this port is physically mounted within the LA36 cabinet.
1.3 TECHNICAL CHARACTERISTICS
The technical characteristics of the LA36 DECwriter II are listed in Table 1-6. The interface specifications for the
LA36 serial 20 rnA current loop are shown in Table 1-7.
1.4 OPTIONAL FEATURES AND ACCESSORIES
Optional features and accessories are listed in Table 1-6.
1.4.1 EIA/CCITT Interface
The LA36 is optionally available with interfacing capability that complies with the requirements of EIA Standard
RS-232-C and CCITT Recommendation V-24. It is supplied with a 9-ft cable terminated in a standard EIA connector
(Figure 6-53). The cable mounts through the interface opening in the bottom of the LA36 chassis and plugs into
connector J4 on the LA36 Logic Board. Connector pins are shown in the Table 1-8.
1-12

Table 1-5
Interface Port Connector Pins
Pin

Function

Unused

-12 V, up to 125 rnA to optional interface

+12 V, up to 125 rnA to optional interface

+5 V, up to 500 rnA to optional interface

Serial output of LA36 to optional interface
TILlevel, will drive 10 unit loads.

Mechanical keying
connection).

Serial input to LA36 from optional interface
TTL level (must be capable of driving 10
unit loads).

Ground

plug (no

electrical

Table 1-6
Technical Characteristics
Main Specifications

Printing Speed: 30 char/sec throughput, serial asynchronous
Number of columns: 132
Printing Characters: 96 ASCII/character set (95 + DELETE)
Control Characters: 32 ASCII/character set
Keyboard Characters: 128

Printing

Type: impact 7 X 7 dot matrix
Character size: 0.175 X 0.25 cm (0.70 X 0.100 in.)
Vertical spacing: 6 lines/inch (2.36lines/cm)
Horizontal spacing: 10 char/inch (3.94 char/cm)
Carriage return: 500 ms max.
Line feed: 33 ms
Slew speed (paper feed rate): 5 in/sec (30 lines/sec) (1.97 cm/sec)

1-13

Table 1-6 (Cont)
Technical Characteristics
Keyboard

Standard ASCII typewriter-like layout, mechanical contact with four parallel switches.

Paper Handling

Tractor feed, 3 engaging pins, movable right-hand tractor for 3 to 14-7/8 in. forms,
manual print gap adjustment for 1 to 6 part forms, vernier vertical adjustment for
custom preprinted· forms.

Paper

Single-Part: 12 to 20 lb. (card up to 0.007 thick)
Multi-Part: 2 to 6 part (no cards except last copy)
Max. thickness (no card) 0.020 in.
Max. thickness (single card, last copy) 0.020 in.
NOTE
NCR or 3M paper (up to 6-part) must use ribbon on top
copy. First surface impact paper is not recommended.
Continuous feed, fan-fold business forms with 3- or 4-prong margin crimps on both
margins (multi-part).
NOTE
Stapled forms are not recommended and may damage
tractors and other areas of the machine. Dot or line glue
margins are acceptable (if line glue is on one margin only).
CAUTION
Do not line glue both margins; air will not be able to escape
and poor impressions will result.

Transmission Rates

110 baud 11 bit, 150 and 300 baud 10 bit; switch-selectable at keyboard panel

Modes of Operation

Local or full duplex on-line, switch-selectable at keyboard panel

Parity

None

Interface

Integrated 20 rnA current loop, full-duplex passive operation. Connectors are 8-pin
Mate-N-Lok type.

Power

90-132 Vac, 48-63 Hz
180-264 Vac, 48-63 Hz
300 W max. (printing)
160 W (non-printing)

Mechanical

Mounting: free-standing pedestal unit
Size: 33.5 in. (852 mm) H X 27.5 in. (696 mm) W X 24 in. (610 mm) D
Weight: 1021bs. (46 kg)

1-14

Table 1-6 (Cont)
Technical Characteristics
Environment

Temperature: 10° to 40° C (50° to 104° F) - operating
-40° to 66° C (-40° to 151 OF) - non-operating
Humidity: 10% to 90% - operating
5% to 95% - non-operating
Altitude: Sea level to 8000 feet (3.04 Km) - operating
Acoustical Noise: Sound pressure level: 65 dB max. between 31.5 and 8000 Hz
Speech interference level: 65 dB max at 500, 1000 and 8000 Hz

Ribbon

Digital-specified nylon fabric, spool assembly 0.5 in. wide X 40 yards
Order # 36-10558

Model

LA36-CA DEC writer II 20 rnA serial interface, 90-132 Vac, 48-63 Hz

OPTIONS
Interface

EIA RS232CjCCITT V-24
DFll Series
Active operation, full- or half-duplex (no charge, customer installable jumpers)

Parity

Even parity (no charge, customer installable jumpers)

Numeric Pad

II-key

Keyboard Characters

96, LA30 DECwriter compatible (no charge, customer selectable by internal or
external key switch)

Power

180-264 Vac, 48-63 Hz (no charge, customer installable jumpers)

ACCESSORIES

Model Designation

Casters, Shelf and
Paper Tray

LAXX-KA

Casters only

LAXX-KB

Shelf only

LAXX-KC

Paper Tray only

LAXX-KD

Character Set

Non-standard character sets are available.

1-15

Table 1·7
Interface Specifications
Transmitter
(Passive, isolated, goes to "Mark" state when power is turned off.)
Min.

Max.

Open circuit voltage
(of circuit being driven)

5.0V

40V

Voltage drop, Marking

0.5 V

2.0V

Spacing current

0.4 rnA

2.0 mA

Marking current

20mA

80 rnA

Min.

Max.

Voltage drop, Marking

1.2 V

2.7V

Spacing current

0.0 rnA

3.0 rnA

Marking current

15mA

80 rnA

Receiver
(Passive, isolated)

Cable
4·conductor
Standard 15-ft BC05F·15 supplied with LA36
Cable extension is 1500 ft. max.
ReceiverITransmitter
(Active, half-duplex)
Min.

Max.

Voltage drop, Marking

1.7 V

4.7V

Spacing current

O.OmA

3.0 rnA

Marking current

15mA

80 rnA

1·16

Table 1·8
EIA/CCITT Interface Connector Pins

Pin No.

EIA Circuit
Designations

Protective Ground (electrically
connected to the LA36 chassis)

Signal Ground (common return)

Transmitted Data (from keyboard)

Received Data (to printer)

Request to Send (always asserted)

Data Terminal Ready (always asserted)

Circuit Descriptions

1·17

CHAPTER 2
INST ALLATION

This chapter outlines unpacking and inspection procedures, installation, cable connections, and unit checkout. A
brief discussion of site considerations is also provided.
2.1 SITE CONSIDERATIONS
The LA36 DECwriter II should be located in an area free of excessive dust, dirt, corrosive fumes or vapors. To
ensure proper cooling, the ventilation openings on the sides of the cabinet should have no obstructions within 4 in.
(See Figure 2-1.)
2.2 SYSTEM CONFIGURATION
Adequate clearance must be provided for servicing the machine. Figure 2-1 illustrates cabinet service area
dimensions.
2.3 UNPACKING AND INSPECTION
To unpack and inspect the LA36, proceed as follows:
1.

Remove the outer cardboard shipping container carefully so as not to damage any of the inner contents.
(Use care when using carton knives and prying tools.)

Remove all shock absorbing laminated material from around the printer and set it aside.

Remove the poly bag from the printer and discard it.

Remove the foam pad from the top of the keyboard along with the two mament tapes that secure it to
the frame.

Lift the LA36 cover and clip the cable tie that secures the head in the left-most position.
CAUTION
Do not allow the tie to fall into the machine.

Inspect the external surface for possible shipping damage. Check the packing list. Report any damaged
or missing items to the local DEC Field Service or Sales Office.

Ensure that the cover hinge and fasteners are intact.

If it appears that the cover has been dislodged in shipping, inspect the internal mechanical parts to see if
damage has been done.

2-1

--.

rO-..

--,-

III

\--E---to
0----

'..---

--B---.l-I

"'-1-

...

:
I
DIMENSIONS

INCHES

33.5 27.5

V* 96

MILLIMETERS

852 696 356 610

V* 2440

* CURRENT LOOP CABLE (BC05F) LENGTH IS
VARIABLE; EI A CABLE LENGTH IS 9 FT
(2744mm)

---------..,

SERVICE
AREA

I
I

I
I
I

~ _ 31
D

'-T-------'----J
I

I
I

I
:
SERVICE
I
I
AREA
I
L __________ J
Cp·I572

Figure 2-1 Site Considerations

Check to see that the keyboard bezel has not shifted (keys should not bind).

10.

Open the rear access door and check the security of all connectors.

11.

Locate the DECwriter II near its operating position.

2.4 INSTALLATION PROCEDURE
The LA36 DECwriter II is equipped with leveling feet. It is not necessary to bolt it to the floor. To install.the LA36,
proceed as follows:

Locate the DECwriter II at its fmal operating position.

Adjust the leveling feet on the stand until the unit is leveled.

2-2

If necessary, wipe all outer surfaces with a clean, soft, lint-free cloth.

Remove the power cable from its storage position and connect it to the power source.
CAUTION
Before connecting the LA36 to local power, ensure that line
voltage and frequency are compatible with the power
requirements of the machine. (See Table 1-6.) Ensure that the
POWER switch on the console is OFF.

Remove the interface cable from its storage position in the cabinet and connect it to the interface logic
designated for that system or remote installation (see Site Plan).
NOTE
Site plans are not supplied by Digital Equipment Corporation.
Interface logic connections must be specified by the system
supplier or the customer because each installation may be
different.

Upper Case and Lower Case Character Selection - To set up the LA36 so that it will only print upper
case characters, set the slide switch on the printed circuit board of the Keyboard Assembly to the proper
position.
The slide switch can be changed in units with serial numbers lower than 6930 by exercising steps 1
through 4 in Section 5.2.3. Then it will be necessary to remove the phenolic locking strip on the switch
to enable it to be changed. This phenolic locking strip has not been installed on units with serial numbers
6930 or higher. With units 6930 or higher, exercise only steps 1 and 2 of Section 5.2.3. Change the
switch by reaching in the opening in the lower left-hand comer of the bezel cover. Refer to Chapter 8
for the switch location.

Parity Setting - The LA36 is configured with no parity. To modify this configuration, insert or remove
jumpers as directed in Table 2-1. Jumper locations are shown in Figure 2-2.

Bell Volume - To lower the volume of the bell tone, cut jumper WI.

Current Loop - The LA36 is normally configured for full-duplex passive operation. To modify this
configuration, insert or remove jumpers as directed in Table 2-2.

Table 2-1
Parity Configuration Jumpers
Function

WI0

8th Bit Marking

Even Parity

Legend: 0 =Jumper inserted
1 =Jumper not inserted

2-3

o 0 oO~QO 00
O!Uoo¢o

OQO

00 0 o

10 00 oo
CP-1573

Figure 2-2. Jumper Location Diagram

2.5 CHECKOUT AND ACCEPTANCE PROCEDURES

Check the follOwing items before running the electrical checkout procedure.
1.

Open the top cover of the LA36 and ensure that it is equipped with a supply of ribbon, threaded
through t6 the take-up reel. If not, install as directed in Chapter 3.

Install paper as directed in Chapter 3.

Connect the LA36 to the correct power source and set the POWER switch to ON. If the fan does not
run, refer to symptom 1 of Table 5-2.

Set the POWER switch to OFF and then to ON; observe the initializing operation of the print head. The
head should move to the right, then to the left as far as the stop, then back to the right and stop at the
4th character position - Last Character Visibility (LCV). If the print head does not initialize correctly,
refer to symptom 2 of Table 5-2.

2-4

Table 2·2
Current Loop Configuration Jumpers
Jumper

W12 W32 W54

Full-Duplex Active

Full-Duplex Passive

Passive Receive/
Active Transmit

Active Receive/
Passive Transmit

Half-Duplex Active *

Half-Duplex Passive *

*Connect user-manufactured cable between J3-3 and 5 and operating system.

Legend: 1 = Jumper inserted
0= Jumper not inserted

Set the BAUD RATE switch to 300 and the LINE/LOCAL switch to LOCAL.

Press the LINE FEED key and then hold down the CTRL key and press the BELL key. The stepping
motor should advance the paper one line and the bell tone should sound. If not, refer to symptoms 3
and 4a of Table 5-2.

Press the / (slash) or @ key and the REPEAT key. The print head should travel smoothly along the print
bar and print the corresponding character. When the print head passes the 64th character position, the
bell tone should sound. If the bell tone does not sound, refer to symptom 4b of Table 5-2. If the print
head hangs up trying to print a character, refer to symptom 5 of Table 5-2. If other symptoms appear,
look for the corresponding symptom in Table 5-2.

Press the BACKSPACE key. If the print head does not move one character position to the left, refer to
symptom 13 of Table 5-2.

Press the RETURN key after 132 characters have printed and observe the return of the print head to the
"home" (LCV) position. It should take approximately 1/2 second. If it takes longer, refer to symptom
12 of Table 5-2.

10.

Set the BAUD RATE switch to the setting prescribed for the operating system.

11.

Set the LINE/LOCAL switch to LINE and run customer-provided programs to check that the unit
operates satisfactorily when connected to the system.

2-5

CHAPTER 3
OPERATION

3.1 OPERATOR CONTROLS
The LA36 DECwriter II operator controls are described in Table 3-1 and illustrated in Figure 3-1.
Table 3-1
Control and Function Keys
Description

Control/Key
CTRLKey

Holding down the CTRL key when a character is typed forces bits 6 and 7 of the
ASCII code for the character to O. For example, the ASCII code for the letter
"g" is 147 (1100111)

Holding down the CTRL key and typing g transmits ASCII code 007

The CTRL key enables the LA36 operator to transmit all ASCII control codes
(000-037).
BREAK Key

The BREAK key is commonly used to forcibly interrupt the flow of data
coming to the LA36. It is provided for users with software written for
half-duplex operation.

In half-duplex operation, only one set of lines exist between the terminal and
the host computer. If the host computer has control of the lines, BREAK is the
only means of forcing an interrupt.
POWER Switch

The POWER switch controls the ac line voltage to the LA36.

LINE/LOCAL Switch

The LINE/LOCAL switch connects the LA36 to the transmit and receive lines in
the LINE position, and disconnects it in the LOCAL position.

ESC(SEL) Key

The ESC(SEL) key enables the LA36 operator to generate an Escape command.
Standard programming conventions dictate that receipt of ESC (ASCII code
033) directs the receiving device to treat the next character as a command.
Commands encoded in this manner are called Escape Sequences. It is the
responsibility of the host computer programmer to define the exact Escape
Sequence for each application.

3-1

Table 3-1 (Cont)
Control and Function Keys
Control/Key

Description

TAB Key

The TAB key generates ASCII code OIl. The programmer must design the
software to translate TAB commands into the proper number of space
commands to be sent back to the LA36.

LINE FEED (LF) Key

The LINE FEED key generates ASCII code 012. The MPC advances the paper
one line each time LF is typed.
NOTE
Rapid off-line paper advance may be accomplished by placing
the machine in LOCAL and depressing the LF and REPEAT
keys simultaneously.

BACKSPACE Key

The BACKSPACE key generates ASCII code 010. The microprogram moves the
print head one position to the left each time the BACKSPACE key is typed.

RETURN Key

The RETURN key generates ASCII code 015. The microprogram positions the
print head at the left margin each time the RETURN key is depressed.

REPEAT Key

The REPEAT key, by itself, transmits no code to a host computer. Holding
down the REPEAT key and depressing a character key causes the ASCII code
for the character to be transmitted repeatedly at 15 cps until either the REPEAT
key or character key is released.

BAUD RATE Switch

The BAUD RATE switch controls the rate at which characters are transmitted
and/or received.
Switch Position

Character Rate

110
150
300

10 char/sec
15 char/sec
30 char/sec

Carriage Adjustment Lever

The carriage adjustment lever controls the print head gap for single- or multi-part
forms.

Tractor Adjustment Knob

The Tractor Adjustment knob releases the tractor, allowing the use of paper of
varying widths.

Paper Advance Knob

The Paper Advance knob pushes in and disengages the line feed gear train to
allow fine vertical adjustment of paper position.

Ribbon

The ribbon reverses automatically. It must be periodically turned over and/or
changed.

3-2

BACK
CTRL

ESC (SELl
KEY

TAB KEY

LINE FEED

SPACE

KEY

BREAK KEY
KEY
NUMERIC

PAD
(See IPBI

SWITCH
7037 -6

Figure 3-1 Operator Controls

3.2 OPERATING PROCEDURES
3.2.1 Loading Paper
1.

Set POWER switch to OFF.

Move the Carriage Adjustment Lever (Figure 3-2) toward the keyboard as far as possible; this creates
space for inserting paper.

Place tractor-feed paper on the floor between the legs of the LA36. (The term tractor-feed refers to the
holes.Qn either side of the paper.)

Open both tractor covers (Figure 34) so that the tractor pins are exposed. Insert the left side of the
paper with the holes aligned directly over the tractor pins. Close the left side tractor cover.

Feed the paper through the load channel under the terminal. Draw the paper up as it passes between the
print head and the print bar (Figure 3-3).

3-3

""]..~ ".," tJ'11O:)

•

,~
1M

(><.01.

l...

""-

:::-.'

A~nf~H::
•

,,8

~~~---. .. ~---~

Figure 3-2 Carriage Adjustment Lever

Loosen the Tractor Adjustment Knob (Figure 3-4) on the right tractor (about 1/4 turn). The tractor will
now slide freely to the left or right. Slide the tractor to a position where the holes on the right margin
align directly over the tractor pins. Tighten the tractor adjustment knob and close the cover.

NOTE
In order to ensure proper paper feeding, do not tension paper
too tightly. If tension is excessive, the following problems may
occur:
1. Paper holes will be distorted.
2. Paper may become dislodged from tractor.
3. Spacing between lines may become uneven.
7.

Adjust the carriage adjustment lever so that the print head is near, but not exerting pressure on the
paper. There should be no friction between the paper and the print head as either moves.
The right side of the carriage is numbered 1-7; positions 1-6 correspond (approximately) to 1-6 part
forms.

3-4

70 37-3

Figure 3-3 Paper Loading

To check for proper print head alignment:
a.

Manually tum the Paper Advance Control counterclockwise. If the print head is set too close, the
paper will be smudged as it moves up past the print head.

Set the POWER switch to ON; set the LINE/LOCAL switch to LOCAL. Type a short line of text.
If the print head is too far from the paper, the ~haracters will not print or they will not have
uniform dot density .
CAUTION
Failure to properly adjust the print head gap can reduce the
life of the head.

The Paper Advance Knob (Figure 3-5) can be pushed in to position the paper such that the text is printed directly
above the horizontal lines. Type a short line of text to check paper positioning.

3-5

TRACTOR
ADJUSTMENT
KNOB

Figure 3-4 Tractor Adjustment Knob

PUSH IN HERE
AND TURN
TO ADJUST PAPERVERTICALLY

PAPER
ADVANCE
KNOB

Figure 3-5 Paper Advance Knob

3-6

TRACTOR
COVER

3.2.2 Changing Ribbon
The printer ribbon should last for 8 to 12 hours of actual printing at 30 characters/second or about one million
characters. After 12 hours, or if the printout density becomes too light, remove both ribbon spools from their drive
spindles and tum the whole assembly over so that the previous lower edge of the ribbon is now on top. Mter
rethreading the ribbon, another 4 hours (approx.) of printing time is possible before the ink is completely used up.
At that time, the ribbon must be replaced by removing both spools and unthreading the ribbon. Replace with a new
spool and ribbon assembly (#36-10558) and an empty spool. (One of the old spools may be used if desired.)
1.

Set POWER switch to OFF.

Raise the top cover.

Move the Carriage Adjustment Lever (Figure 3-2) toward the keyboard. This moves the print head away
from the paper to create enough space to remove the ribbon.

Lift the ribbon (Figure 3-6) off the print head and unwind it from the idler spools.

Lift the two ribbon reels from their hubs.

Place the full reel of new ribbon on the left hub and play out enough ribbon to feed through the slot,
around the idler spools, and in front of the print head.
Wind the ribbon around the outside of the right-hand idler spools and through the right-hand slot in the
Ribbon Direction Changing Guide.
NOTE
Use only Digital recommended ribbons (part No. 36-10558);
use of other than Digital recommended ribbons can cause
damage and void machine warranty.
Ensure that the rivet is on the ribbon spool side of the Ribbon Direction Changing Guide.
The ribbon direction guides control the direction of ribbon movement. When the ribbon on the left reel
is nearly played out, the rivet is drawn into contact with the direction changing guide. Since the rivet
cannot pass through the guide, it moves the guide away from the reel, automatically changing the
direction of ribbon flow. If the rivet is on the print head side of the guide, it will:
a.

Not act to change ribbon direction

Move around the idlers, stall the machine and blow the 2 A Slo Blo servo fuse.

Take up any slack in the ribbon by turning the takeup reel clockwise.

Return the carriage adjustment lever to its original position.
CAUTION
Head life may be reduced if carriage lever is not properly
adjusted.

3-7

Figure 3-6 Ribbon Direction Changing Guide

3-8

3.2.3 Troubleshooting
Operator.related troubleshooting information is listed in Table 3·2.
Table 3·2
Operator Troubleshooting
Possible Cause and Corrective Action

Symptom
LA36 does not tum on when
POWER switch is set to ON

Print head does not print
characters

light print

•

AC power cord is not plugged into wall outlet - plug it in.

•

Current is not coming from wall outlet - check outlet with a known
working electrical device (such as a lamp).

•

Interface cord might be loose and thus a contact may not be
made - '~iggle" the cord slightly.

•

Print head may be set too far from paper - adjust the carriage
adjustment lever as directed in Table 3·1.

•

Print head may be set too far from paper - adjust the carriage
adjustment lever as directed in Table 3·1.

•

Ribbon ink has run out - replace ribbon.
Change ribbon every 8-12 hours of continuous printing.

•

Improper loading of paper - check tractor covers to ensure that they
are closed.

•

Holes in paper are tom - tum LA36 OFF and reload paper properly.

•

Paper snagged or caught by box.

•

Print head is exerting pressure on paper so that paper tears when it
advances - check carriage adjustment control lever position.

•

Tension exerted on the paper by the tractors is incorrect. Adjust by
changing horizontal position of right hand tractor.

line bunching

•

Tension exerted on the paper by the tractors is excessive. Adjust by
changing horizontal position of right hand tractor.

No keyboard or printer
response

•

LINE/LOCAL switch set to wrong position.

Paper does not advance

Paper tearing on multi· part
forms

3·9

3.3 CAUTIONS
Keep the cover closed at all times except when changing the ribbon.
Use only a lint-free cloth when cleaning the cover and the keyboard. Do not use solvents or harsh cleaning agents to
clean the LA36. If excessively dirty, a mild detergent solution or desk top cleaner may be used sparingly.
Do not use any LA36 surface area to hold pendils, paper clips, staples, etc. If an object accidently falls into the
machine, tum the POWER switch to OFF, unplug the power cord from the wall outlet, and carefully remove the
object.
Tear paper only along perforations. Support paper on the LA36 cover when tearing to avoid distorting the
tractor-feed holes in the paper still in the machine.

3-10

CHAPTER 4
THEORY

This chapter contains microprogram information, timing, detailed control logic theory, and mechanical theory for
the LA36. The program description is divided into two parts. The first part (Section 4.1) is a general description
supported by a flow diagram. The second part (Sections 4.1.1 through 4.1.11) is a series of detailed descriptions of
the routines supported by detailed flow diagrams. A detailed description of the Scratch Pad Memory is presented
before the routine descriptions.

The control logic theory is also divided into two parts. The first part (Section 4.3) is a functional system description
supported by a block diagram. The second part (Sections 4.4 through 4.13) is a series of detailed descriptions of the
functional systems supported by block diagrams and detailed logic diagrams. Mechanical theory of operation is
presented in Section 4.14. The mechanical deSCriptions are supported by Simplified diagrams. The logic functions
and signal names that are used in these diagrams and deSCriptions are cross referenced to improve usability.
For example, DEC 1 (Decoder 1) is a logic function that appears on a block diagram. The location of this function in
both the simplified and detailed logic diagrams is identified by the notation, MPC4 (Microprogrammed Controller,
page 4). Signal names, SET HDE for example, are cross referenced in the same manner, using the signal source for
reference. Thus, a complete cross reference is:
DEC I

SET HDE

logic function

signal name

---r-

MPC4

page location

Signal abbreviations are explained in Appendix A, Table A-2. This table also lists signal source and destination
information. A complete set of logic diagrams is provided in Chapter 7.
4.1 PROGRAM DESCRIPTION
The microprogram consists of several instruction sequences connected by major decision nodes as shown in Figure

4-l.
The first sequence is the Initialize (INIT) routine. This routine initializes all the control RAM locations and moves
the print head to the left margin. The next sequence is the Position (POSIT) routine. Requests for print head
position changes (such as for print or carriage return) are processed. All position information is in units of character
cells and is stored in locations of the control RAM (Random Access Memory). In addition, indications of print head
position change are processed. (CARRY is equal to one column reverse.) The SERVO routine interacts with the
POSIT and SPEED routines to correct position error. In the SPEED routine, a SPEED is commanded to the Carriage
Servo System based on the difference between actual and desired print head positions. Possible speeds include
3 in./sec for normal printing, 6 in./sec for catch-up mode, 50 in./sec for carriage return, slower speeds for carriage
return slowdown, and 0 in./sec for idle.

4-1

AR-OOOO ." POWER UP

ENTERS
AFTER
208CLK
SYNC

PRINT EXIT
WHILE SYNC
ON INC.

CP·1379

Figure 4-1 Microprogram Flow Diagram

4-2

The INPUT routine operates the Character Buffer Address register as a First-In/First-Out (FIFO) memory. It uses
three locations of the control RAM as read address, write address, and word count.
The BELL routine activates the Bell System and times the duration of the audible tone bursts.
The PRINT routine requests print head motion and activates the print head solenoids to form the 7 X 7 dot matrix
characters. The LINE FEED routine times the four steps and the settling time for the line Feed Stepper System.
The Last Character Visibility (LCV) routine is entered when no character is being processed. It times the head
step-over delay and requests print head motion.
The NEXT routine is the mate to the INPUT routine. It processes characters out of the FIFO memory and sets up
the conditions in the control RAM which will cause their execution.
If the character to be processed is printable, the PRINT routine is activated. If necessary, a recovery from the LeV
position is requested. If the column is 64 and the keyboard has been active on this line, the end-of-line warning is
sounded.
If the character is carriage return, the desired print head position change is entered in the control RAM. The POSIT
and SPEED routines complete the execution of carriage return. Backspace is processed in a similar manner.
If the character is line feed, then the line Feed Step Timing sequence is initiated.
If a bell character is received, the BELL routine is notified. Up to eight sequential bell characters can be processed
and will sound as separate tone bursts.
AU other characters cause no action. If 132 characters have been printed on the current line, normally printable
characters also cause no action. Thus, overprinting does not occur.
4.1.1 Scratch Pad Memory
The variables that are monitored by the microprogram are stored in the control RAM (Random Access Memory),
which is used as a Scratch Pad Memory. Memory locations are utilized as listed in Table 4-1.
The control RAM provides space for 16 words to keep track of various operational conditions within the LA36
during its operating cycle. Each memory location in this control RAM is 4 bits wide. Some locations are dedicated
exclUSively to a specific function and other locations are shared. The dedicated locations are used for those functions
that need to be monitored at all times; the shared locations are used for variables that are applicable only during
certain times in the operating cycle of the machine; e.g., at one portion of the sequence it is important to keep track
of position error but in other portions it is important to time a line feed, print, or Initialize function; but because
these functions are mutually exclusive in time, they can share the same set of bit positions in the control RAM. Note
that these various functions do not use exclusive bits in a particular location but rather use all four bits of that
location at different times. An exception is location 12 in which the variable "Print" is continuously stored in the
least significant bit position of that word while timers for LCV, line Feed, Print, and Initialize are alternately stored
in the upper three bits. When timing, these bits are incremented each time by 2 instead of 1 to preserve the proper
state of the LSB which is (1) for Print and (0) for line Feed.
Locations 0, 1, and 2 of the control RAM are used to monitor carriage position within each printable line and are, at
all times, an indication of where the head (or carriage) is actually located. Locations 3 and 4 provide a total of 8 bits
that indicate the column in which the last character was printed (or, in a sense, where the carriage should be
located).

4-3

Table 4-1
Scratch Pad Allocations
Octal Location

Mnemonic

POSLO

1
2

POSMD
POSHI

COLLO

COL HI

RDADR
LCV 1

Character Buffer Read Address
LeV Timer

WfADR
LCVl

Character Buffer Write Address
To Keep Wf ADR=RD ADR

WOCNT

Character Buffer Character Count

Usage
12-Bit Carriage Position
(Relative to column)

8-Bit Column Count
(Records columns printed)

Unused

COUNT

Print Dot Count, LF Pulse Count

PRINT
LCV2
LF 1
PT 1
INIT 1

LSB= 1 for Print
LCVTimer
Line Feed Timer
Print Timer
Init Timer

POSER
LF2
PT2
INIT2

Position Error
Line Feed Timer
Print Timer
Init Timer

LCVST
LCV3

LCV Status
LCVTimer

BELLI

Bell Timer

BELL 2

Bell Timer

BELLST

Bell Count (Status)

Positions 5, 6, and 7 are used to control the operation of the character buffer (FIFO). These are Read Address, Write
Address and Word (Character) Count. When the Word Count (WC) is equal to 0 (Buffer Empty) it does not matter
what the Read or the Write addresses are if they are equal to each other. This ensures that upon receipt of the next
character, these addresses will continue to track each other.
The Read and Write addresses in positions 5 and 6 share those positions with one of the LeV timers for timing out
the 1.3-second head step-over function for LCV. This.is feasible because LeV will occur only when WC is equal to 0;
while the Read and Write addresses are. equal these positions are available for timing that function. Upon receipt of
the next character from the UART, the Write address and WC are incremented. When that character is read out of
the buffer, the Read address is incremented, creating an equal condition again between locations 5 and 6.

4-4

Location 11 is used in combination with location 12 as a counting location for either the dot print or line feed
functions. As previously stated, the LSB of location 12 is set during dot printing and cleared during line feeding.
These states are maintained by incrementing the timer ·bits in location 12 by 2 each time instead of by 1. When the
Count in location .11 is zero, the printer is neither printing nor line feeding and location 12 can be used as an LCV
timer. Location 12 is also used as a timer during Initialize.
Location 13 is used as a pOSition error count for use by those routines that alter the position of the carriage by
anything less than 8 columns in either direction. These routines are Print, which alters the position by I to print the
next character and LCV, which changes the position by +4 on an interruption of printing and by -4 on a resumption
of printing.
Backspace, which is not represented on such in a scratch pad location, is implemented by manipulation of position
error in location 13. When that location is decremented by 1, the Position Count in locations 0, 1, and 2 are used in
the SPEED routine to command the head to move back one column.
Location 14 contains LCV Status and LCV Timer information. Although LCV Status is required only when WC=O, it
must be preloaded to a value (128 ), which when counted up to zero, will consume 1.3 seconds (the time delay
required before the head is moved to the right 4 columns for LCV). This preloaded value becomes the most
significant part of the LCV timer.
Locations 15, 16, and 17 are used to control the bell. To sound the bell, a 2.4 kHz clock from the logic is gated to
the loudspeaker with a flip-flop that is, in turn, controlled by the microprogram. In this way, the microprogram
determines both the length of the bell tone and time between bell tones.
Bell tone ON/OFF time is set at 106 ms. This is timed in locations 15 and 16. Location 17 is a Bell Count or status
position, allowing up to 8 bell tones to be executed continuously. By using this scheme, successive bell codes can be
sensed and accumulated at a rate of 30 per second without the necessity of intervening fill characters, and then
applied to the speaker at a rate of about 5 tones per second. A graphic demonstration of this is seen when it is
realized that the 9th bell code would be received before the first bell tone had ceased.
4.1.2 Initialization Routine (IN IT)
The LA36 power up circuit holds the Address Register (AR) at zero and inhibits the system clock until dc power is
up (within 300 to 700 rns). At the end of this period, the AR is left at zero and the first instruction is executed. This
instruction tests the INIT and if set, causes the program to enter the INIT routine (Figure 4-2).

This routine clears all flags, clears the control RAM, clears the function enable latches, and sets a low negative
velocity for the carriage. When the carriage finds the left travellirnit, the left-hand margin pOSition is set to zero,
INIT is cleared, and the program progresses to the POSIT routine. This routine is never reentered except in the event
of a power down.
4.1.3 Position Routine (POSIT)
The POSIT routine (Figure 4-3) is very closely interrelated with the SPEED routine. As described in the discussion
of the scratch pad allocations, the first three locations are a constant indication of actual carriage position, and the
next two locations are a constant indication of the desired carriage position. Every time the carriage is moved for
any purpose, the first three locations are changed accordingly, and every time the printer is caused to print a
character, the next two locations are modified. When these two counts are equal, no carriage motion occurs, but
when they are unequal, a position error is generated and an appropriate SPEED command is issued to constantly
keep these two sets of locations equal to each other. Because of this, some motion of the printer can be caused by
the program simply by altering these variables in the control RAM location dedicated to that particular monitoring
function.

4-5

TIME OUT 400 MSEC (FOR INIT)

INIT
CLR BELL
SET LF HOLD
SPEED· -6 IPS
CLRINC
TIME OUT
400 MSEC
=1

COL LO: =0
COLHI:=O
RD ADR: =0;
WTADR:=O
WDCNT: =0
CNT: =0;
LCVST: -0
BEL2: =0;
BELST: = 0

POS HI: =-1
POSMD: =-1
POS LO: =-5

1 PASS EVERY
416"S

(POS= -51

CLR KBH
LOAD INC
CNTR/CLR
INIT

Figure 4-2 Initialize Routine

CP-1624

Figure 4-2a Start Routine for Initialize

4-6

pos: = POS+l

(FOR POSIT)

'FLOW THROUGH
HERE GENERALLY
EVERY 416"S.

-1

LINE FEEO NOT
IN PROCESS

LINE FEED
IN PROCESS

CP·1626

Figure 4-3 Position Routine

Figure 4-3a Start Routine for Position

4-7

The operations that alter these position variables as a result of carriage motion are Carriage Return (CR), LCV, and
Print. The function that causes carriage motion as a result of altering the variables is Backspace. Line Feed and Bell
do not affect the position of the carriage.
When a CR is received and processed, the program sets the Column Count to zero, thereby causing the SPEED
routine to issue a suitable negative SPEED command that causes the carriage to return to the zero column position.
In LCV, if a timeout has completed following receipt of the last character, -4 is put in position error, while true
column position is preserved, thereby causing the SPEED routine to command the head to move four columns to the
right. In Backspace however, one is subtracted from the true column position so that the validity of the column
variable is preserved.
The POSIT routine, on the 208 JlS clock, checks Bell Status and, if zero, clears the bell and checks Print. If Print is
not zero, it checks the Print Bit and if it is a one, indicating no LF in progress, sets LF HOLD and proceeds. If LF is
indicated by the Print Bit being 0, the count is checked to see if it has completed that line feed, and if it has not
(non-zero count) it proceeds to the SERVO routine to continue that operation. If count is zero, then the line feed is
complete and it sets LF HOLD before proceeding with the POSIT routine.
At this point the program checks the position error variable and, if it is zero, proceeds to the SERVO routine. If an
error exists (non-zero), it checks the degree of error and its direction (positive or negative) on a triple-precision basis,
and corrects the error by incrementing or decrementing the position variable until no carries or borrows are sensed.
This is the only time that any SPEED commands are issued to the Carriage Servo System. All SPEED commands are
a function of POSIT, WC, and Print as determined in the SPEED algorithm; and all processing of carriage position is
done by the POSIT routine, whether the printer is doing a carriage return, printing, or just correcting position
randomly.
4.1.4 SERVO Routine
The SERVO routine (Figure 4-4) interacts with the POSIT and SPEED routines. In this routine, the carries and
borrows that are generated as the head moves through character cell boundaries are checked and cleared until the
position error is corrected. Each time a carry or borrow is sensed, it is cleared and the program returns to the
appropriate node in the POSIT routine. Finally, when no carries or borrows are sensed, the program proceeds to the
SPEED routine.
4.1.5 SPEED Routine
The SPEED routine (Figure 4-5) checks the position variable in the first three locations in the control RAM on a
triple-precision basis, and considers Word Count in location 7, the Print Dot Count in location 10, and the state of
the Print Bit. The SPEED algorithm is represented statistically in Table 4-2.
The first pass through the program is implemented for situations in which either the returning carriage has overshot
its mark or the carriage has been accidently moved left while the printer was static in an LCV state. The program
checks position relative to Column Count and finds it less than zero. At this point the program checks Word Count
and if it finds it zero (no characters to be processed) it causes the SPEED routine to command a speed of +3 ips (+
speed = print motion; - speed = return motion). If there are characters to be processed (yrIC not equal to 0), it
commands a speed of +6 ips to clear the buffer, proViding ample time to be ready to print the next character.
If in checking the high order position bits for zero, the program finds them not equal to 0, the actual carriage
position is indicated to be positive (to the right) and greater than 16 columns from where it should be. This results in
the maximum SPEED command of - 50 ips being issued.

4-8

-G=IGURE 4-3

YIGURE4-3

CP-1627

Figure 4-4 Servo Routine

Table 4-2
SPEED Algorithm
Speed (ips)
Count =0
Print = 1

WD
CT

Position
~ 16
~8
~4

=0
=1
=1

=0
=1
=0
=1

=1
=0
=0
=0
<0
<0

4-9

+ = Print
- = Return Motion
-50
-30
-20
-10
-6
0
+3
+6
+3
+6

(PDS LO--POS MDPOS HI VERSIONI
(ACTUAL IMPLE·
MENTATIONI

SPEED: ~ -50 IPS

CP-1628

Figure 4·5 Speed Routine

4·10

(

As the carriage begins to move in response to this command, the program loops through its sequence checking the
middle four, and then the low four bits of POSIT; and, as each condition is satisfied, the SPEED commands are
diminished to cause the head to slow down smoothly until it has reached the correct position. At this point, carriage
motion stops and the program enters the INPUT routine if the Count is zero. If it is not zero, the Print Bit is
checked and if it is cleared, a LF is indicated and a speed of 0 ips is commanded to complete the LF function. If the
Print Bit is set however, WC is checked to see if a positive speed of either +3 or +6 is required to print the current
character without lOSing the next character.
4.1.6 INPUT Routine
The INPUT routine (Figure 4-6) checks DART Data Available (DA) and if cleared (no character) it steps
immediately to the BELL routine. If DA is set, the program checks Word Count (WD CT) to see if the Character
Buffer is full (WD CT=15). If so, it ignores any input from DA, using the UART as the 16th memory location, and
proceeds immediately to service the bell.
NOTE
The UART can act as the 16th memory location for up to
33 ms even though data is available. After this period the
character will be lost when the UART writes in another
character.

WDCNT: =
WDCNT+l

CBA:·
WTADR
CB ICBA]: =
UARTOUTPUT
CLRUARTDA
CBA: = RDADR

CP·1629

Figure 4-6 Input Routine

4-11

If WD CNT is not equal to 15, Word Count is incremented, Write Address is incremented, the character is put into
the buffer at the new Write Address, and UART DA is cleared as the program proceeds to the BELL routine.

4.1.7 BELL Routine
!

The BELL routine (Figure 4-7) turns the bell on for 106 ms and off for 106 ms, for each bell that is received and
stored in the Bell Status location in the control RAM.

-0

",0

CP-1630

Figure 4-7 Bell Routine

4-12

If Bell Status is zero, no bells are required and the routine falls through to check Count, Print, and Word Count.
Here the decision is made to process either a Print,' a LF, or the next character, or to execute an LCV.
If Bell Status is not zero, the status is checked to see if it is odd or even (for each bell code received, two counts are
stored in status, one to turn it on and one to turn it off).
The bell timers in location 15 and 16 provide 4-bits of each CounL The bits in either location 15 or location 16 are
incremented during each pass until that timer has reached zero (106 ms) and Bell Status either becomes odd and the
bell is turned off, or even and the bell is turned on. Each pass through the loop takes 4161-1s and it takes 256 passes
to fully cycle each timer, providing 106 ms of on time and 106 ms of off time. Each time a timer reaches zero, one is
subtracted from Bell Status until the total number of bells commanded have been executed.
4.1.8 PRINT Routine
Before entering the PRINT routine (Figure 4-8), the program sequenced through the BELL routine where it found
that the Count location was not zero and that the Print ,Bit in location 12 was set, indicating that a printable
character was in the buffer. These conditions caused the program to enter the PRINT routine.
Upon entering the PRINT routine, the program checks the position locations to be sure that they are all equal to
zero. This is done to prevent the start of print at some position other than the beginning of the character cell.
The program checks position from low order through high order in 4-bit bytes, and if any are non-zero, it checks
Count and returns to the POSIT routine, looping until Count is less than the seven dot positions of a character. At
this p'- t it sets Count to zero, loops once more through POSIT and returns to PRINT.
In this pass, the program drops through to check Count again. This time Count should equal 8 as set in the NEXT
routine. The program verifies this by checking the MSB of location 11 in the control RAM. If this bit is set, it signals
the start of print (meaning that the head should start moving to the right). To start this motion, the program
subtracts one from Position Error, sets Count to 7 (to prevent a repeat of this branch), and returns to POSIT to loop
through again so that the SPEED routine can command head motion.
This time through, POSIT is still 0 relative to column, Count is less than 8 (7); the program presets the Print Timers,
and clears the Increment indication. It waits then for Increment to set, and when it does it sets the 600 J1.S Head
Drive Enable (HDE).
NOTE
At all other times through this routine, operation is
synchronized on the 416 J1.S clock, but at this point
continuation of program flow is predicated on the fact that an
incremental motion of the head has been accomplished.
The 600 J1. HDE is then timed out in PTl and PT2 locations of the control RAM on the 1.184 J1. instruction timin o
cycle of the microprogram. During this time the character is printed. At the end of that time, HDE is cleared, print is
reset to 1, Count is set once again to -1, and the program reenters the POSIT routine.
4.1.9 LINE FEED Routine
. If, while passing through the BELL routine, Count was not equal to 0 and the Print Bit in location 12 is cleared, the
program enters the LINE FEED routine (Figure 4-9).

4-13

+0
+0
600 ,,5 TIMED ON
THE 1.184,,5
INSTRUCTION
CYCLE TIME OF
THE MICRO·
PROGRAM.

~IGURE 4-31
CP·1631

Figure 4-8 Print Routine

4-14

LF=---P1
)

;.8

EVEN

ODD

LFP2

CP-1632

Figure 4-9 line Feed Routine

4-15

Upon entering the routine the program finds Count equal to 9 (as set in the NEXT routine) and a preset in LFl and
LF2. On the trailing edge of the 208 J1.s clock, the LF motor is pulsed and the program returns to POSIT.
Upon reentering the LF routine, the program checks Count and if 8 or more, it checks to see if it is odd or even. If
even (as it should be 8), it decrements Count and uses the timers LFI and LF2 to count out 7.5 ms. At this time a
second pulse is sent to the LF motor. If Count had been odd, a count of 7 would be indicated and 6.8 ms would be
counted before a motor pulse was issued.
The program then counts 3.7 ms and issues a pulse, and then 8.2 ms. This time it sets LF HOLD and returns to find
Count equal to O. This completes the subroutine that issues four discrete motor pulses to step the motor one line
increment and then issues the HOLD signal as part of the last increment.
4.1.1 0 LCV Routine
If, while passing through the BELL routine, both Count and Word Count were found to be zero, the program enters
the LeV routine (Figure 4-10) and places an initial count into LCV Status.

This routine uses the LCV Status (location 14), the Print Timer in location 12 (since printing is not being done), and
locations 5 and 6 in parallel. The latter two locations are normally used as Read and Write addresses, but they are
not needed in this case, so they can be used in parallel to maintain their equality so that the next time they are
required they will function to keep a proper tally on the Character Buffer.
These combined locations then form a 12-bit counter to count the 1.3 sec time delay before the head is commanded
to move four columns to the right by setting -4 into position error.
When the next printable character is sensed in the NEXT routine, the LCV Status is checked (after a check for
column 132) and, if found zero, causes a +4 to be put into position error to move the head back to printing position.
At this time it also initializes LCV Status so that it will count the 1.3 sec the next time it is needed.
From this it can also be seen that LCV ceases and the same initialization of LCV Status occurs if a printable
character is received during LCV timeout.
4.1.11 NEXT Routine
If, while passing through the BELL routine, Count was zero but Word Count was not equal to zero, the program
enters the NEXT routine (Figure 4-1 I).
The program first decrements the Word Count, then increments the Read Address, and puts that Read Address into
the Character Buffer Address (CBA) register causing the character stored at that address to be exposed to the
Character Generator ROM. The ROM is designed to output an additional bit, that when set indicates that the
character is printable, and when cleared indicates that the character is not printable.
At this point, the program enters one of four subroutines to process one of five possible conditions.
If the character is not printable, and it is neither a CR, LF, BELL, orBS, the program exits and reenters POSIT
because the character falls within the control character category that requires no machine action.
If the non-printable character is a LF, the program enters that subroutine. Count is set to 9 and the proper preset is
put in the Line Feed Timer locations before progressing to the LINE FEED routine.
If the non-printable character is a BELL, two is added to the status and the program exits to POSIT.
If the non-printable character is a BS, the program enters that subroutine, where one is subtracted from column
(provided the head is not at column zero) and adds one to position error. The program then returns to POSIT and
then to the SPEED routine where the carriage is commanded to move one space to the left.

4-16

LCV 3 + 1
(LCV ST)

TO POSIT

CP-1633

Figure 4-10 Last Character Visibility Routine

4-17

(

PRINTABLE)

#1 (5 ~S)

(8 X 16 + 4 = 132)
IGNORE CHAR
AFTER COL 132

COL HI: =
COL HI-1

-[!FIGURE 4-9J

TO POSIT

=4
COL=64

CP-1634

Figure 4-11 Next Routine

4-18

If the non-printable character is a CR, the program enters that subroutine. It immediately clears Keyboard Hold
(KBH) and examines the low order bits of the column locations.
The function of this routine is to set Column to zero (since that is where the carriage should be) and to modify the
position location by a factor equal to the number of columns away from column zero that the head is actually
situated when a CR is received.
This is done in the routine in two parts: first the low order bits are examined and then the high order bits. Each
column byte is then decremented and each position byte is incremented until the operation is complete. The
maximum number of passes through this loop is 32, which reqUires 100 /J.S of time to complete the subroutine.
If the Print Bit indicates that the character is printable, the program determines whether or not the carriage is at
column 132. It does this by determining that COL HI is ~ 8 and that COL LO is ~ 4. If these conditions are true,
printing cannot occur and the program returns to POSIT ignoring the current character until a CR occurs.

If Column does not equal 132, Column is incremented and examined again; this time to determine if the head is now
at column 64 (since a bell tone must be sounded at this point if the keyboard is in use).
Since 64 is a multiple of 8, it is only necessary to check for an overflow from the low order of Column to the high
order. The program first checks LCV Status and, if zero, sets 4 in position error. It then puts 4 in LCV Status, sets
Count to 8, and increments the low order of Column. If COL LO is not zero, the program returns to POSIT. If it is
now zero, the high order of Column is incremented. If at this time COL HI does not equal 4, the program returns to
POSIT and when it gets to the PRINT routine, it begins laying down the dots for the character.
If COL HI is equal to 4 after it is incremented, Column 64 is indicated and the program checks KBH. If it is not set,
the program progresses to POSIT and proceeds through the normal print sequence. If KBH is set, the program adds 2
to Bell Status, returns to POSIT, and rings the bell.

4.2 TIMING
The timing of all operations in the LA36 is derived from a crystal clock which operates at 1.6896 MHz. The clock
output frequency is divided by two to form the 1.184 /J.s cycle time for the microprogrammed controller (MPC).
Additional divisions provide timing pulses for the Carriage Servo System and the data communication at 300 baud,
150 baud, and 110 baud. A division of the clock rate is also used by the MPC for timing the LF, BELL, LCV, and
INIT functions. Timing diagrams are provided in the applicable sections of this chapter.
4.3 CONTROL LOGIC
The LA36 control logic is implemented as a microprogrammed controller (MPC). A block diagram of this logic is
shown in Figure 4-12.
Characters from the Keyboard System or the data communications interface are processed through the UART, to
the Character Buffer under control of the MPC. This buffer accumulates characters during a carriage return,
eliminating the need for fill characters. Printing speed is doubled after a carriage return to catch up with the
accumulated characters.
The MPC causes characters in the buffer to be presented to the character generator ROM on a FIFO basis. The
Character Generator ROM generates the dot matrix for the printable characters and contains control character
decode information for the non-printable characters. It also provides a printable/non-printable indication to the
MPC.
The MPC activates the Carriage Servo System and the Print Head System in order to move the print head through a
character cell and print the seven columns of seven dots which form the printable characters.

4-19

2
3

STEP L F - - - - ,

KEY
STROBE

SET HOE - - - - ,

UNIVERSAL
ASYNCHRONOUS
RECEIVER
TRANSMITTER
WART)

CLR

PNTABL
CP-IS77

Figure 4-12 Control Logic Block Diagram

4-20

Upon detection of a CR character, the MPC activates the Carriage Servo System to move the print head to the left
margin. Similarly, a BS character causes the print head to move one character position to the left.
Upon detection of a LF character, the MPC activates the LF Stepper System in order to advance the paper one line.
In response to a bell character or as an end-of-line warning, the MPC activates the Bell System in order to produce an
audible tone.
Transmission of characters from the keyboard, through the UART, to the data communications interface is done
without microprogram control. The act of transmitting a character is stored in the KBD HOLD flip-flop. The MPC
generates the end-of-line warning only on lines in which the KBD HOLD flip-flop has been set.
The structure which allows microprogram control of the LA36 operation is illustrated in Figure 4-12.
The microprogram consists of a sequence of 512 instructions which reside in the control ROM. Each instruction
consists of eight bits. The upper four bits define the general class of instruction; the lower four bits define the
particular operation to be performed.
Selection of a particular instruction in the microprogram is performed by the Program Address register. This register
generally acts as a counter, thus causing instructions to be executed sequentially at the rate of one every 1.184 J.1s.
The Sequential Instruction flip-flop may be interrupted by instructions of the classes referred to as JUMP 1, JUMP2,
JUMP3, CLR, SKIP1, and SKIP2.
The JUMPI instruction causes the Address Control Logic to be activated in order to load the lower four bits of the
instruction (ROM DATA BUS) into the lower four bits of the two-program Address register. Any transfer of control
which does not change the upper five bits of the address may use this instruction and is thus limited to use for jumps
within anyone of thirty-two 16-word pages of the microprogram.
The JUMP2 instruction has the same effect as the JUMPI instruction except that it also uses the four-bit register
Data Bus to load the next four bits of the Program Address register. Thus, the combination of an instruction that
loads the register (described below) and a JUMP2 instruction can affect a transfer within one of the two 256-word
halves of memory.
The JUMP3 instruction is similar to the JUMP2 instruction with the additional effect that the most significant bit of
the Address register is toggled. This causes the jump to be to the opposite half of memory as the instruction being
executed.
The CLR instruction resets the contents of the Program Address register to zero. The Program Address register is
also reset to zero on power up.
The SKIPI and SKIP2 instructions are conditional skip instructions. The conditions are the inputs to MUXI and
MUX2. The lower four bits of the skip instruction specify which of 16 inputs to sample. If the selected input is
asserted when the skip instruction occurs, then the Address Control Logic causes the address to increment by two
rather than by one during a single instruction cycle. Signals which are inputs to the SKIP multiplexers are DART
Data Available, KBD Hold, servo control data (CARRY, BORROW, INC), each of the four bits of REG (BITD, BITt,
BIT2, BIn), the control character indications (CR, LF, BS, BELL), the printable indication, the REG equals D
indication, and a real-time clock.
Instructions which do not modify the normal sequential flow are BRING4, BRING 1, STORE 1, and DEC 1.
The BRING4 instruction performs an immediate load of data from the lower four bits of the instruction to the 4-bit
register (REG). This is accomplished by enabling the 4-bit gate and loading the register.

4-21

The BRING 1 instruction is used to fetch data from one of sixteen 4-bit memory locations in the control RAM to the
REG. The lower four bits of the instruction select the memory location. The instruction is executed by enabling and
loading the memory.
The DECI instruction is the means by which the MPC transmits commands to the systems which it is controlling.
The lower four bits of the instruction specify which of 16 outputs of the DECI decoder will be pulsed. The outputs
of the decoder are CLR UART Data Available, CLR KBH, CLR Carry/Borrow, CLR INC, CLR HDE (combined with
CLR INC), SET HDE, LOAD CB Address, WRITE BUFFER, +1 REG (adds 1 to REG), -1 REG (subtracts 1 from
REG), SET BELL, CLR BELL, Load DAC (D/A) (commands speed to Servo System), CLR INIT (sets left margin at
power up), STEP LF, and SET LF HOLD.
4.4 KEYBOARD SYSTEM
A simplified diagram of the Keyboard System logic is shown in Figure 4-13. The Keyboard System generates the
7-bit, parallel ASCII codes listed in Table 4-3. These codes are stored in a 3600-bit ROM that is controlled by an
internal 10-20 kHz clock. The ROM has a scan cycle time of 6.5-9 ms. It is addressed asynchronously by X and Y
pulses from the KEY MATRIX or the NUMERIC PAD.

BIT I
BIT 2
BIT 3
BIT 4
BIT 5

CONTROL

CTRL
KEY

BIT 7

XO/YO

XIIYI
X2IY2

B2
B3
B4
B5

X3/Y3
X4/Y4
X5/Y5
X6/Y6

KEY
MATRIX

B6
B7

X7IY7

STROBE

X8/Y8

nAY

X6
Y4
Y5
Y6

NUMERIC
PAD

CG
ROM

t!L
X4

...L

PULSE L STROBE
SHAPER (KEY
STB H)

I--

+t
'--

SHIFT

AKO

LOCKOUT

REPEAT
KEY

KEYIKEY 7
UART
MPC6

64/128

DATA READY

CLOCK I---

SHIFTISHIFT
LOCK KEY

BIT6

STROBE
REPEAT
GENERATOR

I
J?----

BREAK
KEY

I BREAK + L
I
GATE MPC5

CP-1578

Figure 4-13 LK02 Keyboard Logic Diagram

4-22

Table 4-3
Keyboard ROM Addressing

Key

Esc
2
r

[
,

=
1

c
g
ill

w
f
n
-

9
q
d
b

BS
8
p

s
v
7
0
a

SP
6
i

{
,
x
5

CR
1

LF
z
4
y

ASCII Code
b7-bl

Octal
Code

0011011
0110010
1110010
1101000
1011011
0101100
0111101
0110001
1100101
1100111
1101101
0110000
1110111
1100110
1101110
0101101
0111001
1110001
1100100
1100010
0001000
0111000
1110000
1110011
1110110
0110111
1101111
1100001
1100011
0100000
0110110
1101001
1111011
0111011
. 1111000
0110101
1110101
0001101
1101100
0001010
1111010
0110100
1111001
0100111
1101011
1011100
0101111

33
62
162
150
133
54
75
61
145
147
155
60
167
146
156
55
71
161
144
142
10
70
160
163
166
67
157
141
143
40
66
151
173
73
170
65
165
15
154
12
172
64
171
47
153
134
57

4·23

ROM Addressing
X Line
Y Line

8
7
5
3
2
1
0
7
5
3
1
7
5
3
1
0
7
5
3
1
0
7
5
3
1
7
5
3
1
8
7
5
4
3
1
7
5
4
3
2
1
7
5
4
3
2
1

9
8
6
4
3
2
1
9
7
5
3
0
8
6
4
3
1
9
7
5
4
2
0
8
6
3
1
9
7
5
4
2
1
0
8
5
3
2
1
0
9
6
4
3
2
1
0

Table 4-3 (Cont)
Keyboard ROM Addressing

Key
HT

3
t
j
DEL
\

ASCII Code
b7-bl

Octal
Code

0001001
0110011
1110100
1101010
1111111
0101110
1100000

11
63
164
152
177
56
140

ROM Addressing
YLine
X Line
8
7
5
3
2
1
0

8
7
5
3
2
1
0

8
7
5
3
2
1
0
7
5
3
1
7
5
3
1
0
7
5
3
1
0
7
5
3
1
7
5
3
1
8
7
5
4
3
1
7

9
8
6
4
3
2
1
9
7
5
3
0
8
6
4
3
1
9
7
5
4
2
0
8
6
3
1
9
7
5
4
2
1
0
8
5

SHIFT MODE

ESC
@

R
H

]

<
+
!

E
G

M
)
W
F
N

(

Q
D

B
BS

P
S
V
&

0
A

C
SP
1\

}
X
%

33
100
122
110
165
74
53
41
105
107
115
51
127
106
116
137
50
121
104
102
10
52
120
123
126
46
117
101
103
40
136
111
175

0011011
1000000
1010010
1001000
1011101
0111100
0101011
0100001
1000101
1000111
1001101
0101001
1010111
1000110
1001110
1011111
0101000
1010001
1000100
1000010
0001000
0101010
1010000
1010011
1010110
0100110
1001111
1000001
1000011
0100000
1011110
1001001
1111101
0111010
1011000
0100101

130
45

4-24

Table 4-3 (Cont)
Keyboard ROM Addressing
ASCII Code
Key

b7-bl

Octal
Code

U
CR
L
LF

1010101
0001101
1001100
0001010
1011010
0100100
1011001
0100010
1001011
1111100
0111111
0001001
0100011
1010100
1001010
1111111
0111110
1111110

125
15
114
12
132
44
131
42
113
174
77
11
43
124
112
177
76
176

Z
$
Y
"
K
I
I

#
T

J
DEL

ROM Addressing
YLine
X Line
5

4
3
2
1
7
5
4
3
2
1

3
2
1
0

9
6

4
3
2
1
0

7
5
3
2
1
0

9
8

CONTROL MODE
ESC
DC2
DC2
BS
ESC
FF
GS
DCl
ENQ
BEL
CR
DLE
ETB
ACK
SO
CR
EM
DCl
EOT
STX
BS
CAN
DLE
DC3
SYN

0011011
0010010
0010010
0001000
0011011
0001100
0011101
0010001
0000101
0000111
0001101
0010000
0010111
0000110
0001110
0001101
0011001
0010001
0000100
0000010
0001000
0011000
0010000
0010011
0010110

33
22
22
10
33
14
35
21
5
7
15
20
27
6
16
15
31
21
4
2
10
30
20
23
26

4-25

7
5
3
2
1
0
7
5
3
1
7
5
3
1
0
7
5
3
1
0
7
5
3
1

6
4
3
2
1

9
7
5
3
0

8
6
4
3
1

9
7
5

4
2
0

8
6

Table 4-3 (Cont)
Keyboard ROM Addressing

Key
ETB
SI
SOH
ETX
NUL
SYN

HT
ESC
ESC
CAN
NAK
NAK
CR
FF
LF
SUB
DC4
EM
BEL
VT

FS
SI
HT
DC3
DC4
LF
DEL
SO
NUL

ASCII Code
b7-bl

Octal
Code

00101 II
0001111
0000001
0000011
0000000
0010110
0001001
0011011
001I011
0011000
0010101
0010101
000 II 01
000 II 00
0001010
0011010
0010100
0011001
0000111
0001011
0011100
0001111
0001001
0010011
0010100
0001010
1111111
0001110
0000000

27
17
1
3
0
26
II
33
33
30
25
25
15
14
12
32
24
31
7
13
34
17
11
23
24
12
177
16
0

ROM Addressing
X Line
Y Line

7
5
3
1

8
7
5
4
3
1
7
5
4
3
2
1
7
5
4
3
2
1
8
7
5
3
2
1
0

3
1
9

7
5
4
2
1
0

8
5
3
2
1
0
9

6
4
3
2
1
0

8
7
5
3
2
1
0

SHIFT AND CONTROL MODE
ESC
NUL
DC2
BS
GS
FS
VT

SOH
ENQ
BEL
CR

HT
ETB
ACK

0011011
0000000
0010010
0001000
0011101
0011100
0001011
0000001
0000101
0000111
0001101
0001001
0010111
0000110

33
0
22
10
35
34
13
1
5
7
15
11
27
6

4-26

8
7
5
3
2
1
0
7
5
3
1
7
5
3

8
6
4
3
2
1
9

7
5
3
0

8
6

Table 4-3 (Cont)
Keyboard ROM Addressing

Key

ASCII Code
b7-bl

Octal
Code

SO
US
BS
DCl
EOT
STX
BS
LF
DLE
DC3
SYN
ACK
SI
SOH
ETX
NUL
RS
HT
GS
SUB
CAN
ENQ
NAK
CR
FF
LF
SUB
EOT
EM
STX
VT
FS
US
HT
ETX
DC4
LF
DEL
RS
RS

0001110
0011111
0001000
0010001
0000100
0000010
0001000
0001010
0010000
0010011
0010110
0000110
0001111
0000001
0000011
0000000
0011110
0001001
0011101
0011010
0011000
0000101
0010101
0001101
0001100
0001010
0011010
0000100
0011001
0000010
0001011
0011100
0011111
0001001
0000011
0010100
0001010
1111111
0011110
0011110

16
37
10
21
4
2
10
12
20
23
26
6
17
1
3
0
36
11
35
32
30
5
25
15
14
12
32
4
31
2
13
34
37
11
3
24
12
177
36
36

4-27

ROM Addressing
X Line
Y Line

1
0
7
5
3
1
0
7
5
3
1
7
5
3
1

8
7
5
4
3
1
7
5
4
3
2
1
7
5
4
3
2
1
8
7
5
3
2
1
0

4
3
1
9
7
5
4
2
0

8
6
3
1
9
7
5
4
2
1
0
8
5
3
2
1
0
9
6
4
3
2
1
0
8
7
5
3
2
1
0

When a key switch is closed for at least 6 ms the X and Y pulses address the corresponding character cell in the
ROM. The timing for character processing is shown in Figure 4-14. After a 2.5-5 ms delay (3 ms nominal) to ensure
that the switch closure did not result from contact bounce, a DATA READY pulse lasting one ROM clock period
(50-100 fJS) is output by the ROM. This pulse is gated to the Pulse Shaper and differentiated to produce a
350-750 ns STROBE pulse, which strobes the parallel data to the UART. The STROBE pulse is also applied to the
STROBE REPEAT GENERATOR together with the AKO (any key depressed) logic level. If the REPEAT key
switch is closed while another key switch is closed (except SHIFT, SHIFT LOCK, CTRL and'TAB), the STROBE
REPEAT GENERATOR produces a series of pulses, one every 46-86 ms. These pulses are gated with the REPEAT
logic level and the DATA READY pulses to repeat the STROBE at a rate of 15 per second as long as the REPEAT
key is closed. The REPEAT logic-level is also applied to the ROM to lock out all other key closures during a
REPEAT.
When the 64/128 switch is open, data bit 6 is gated out. Consequently, only upper case character codes are strobed
to the UART.
The SHIFT, SHIFT LOCK and CTRL key switches inhibit bits 6 and 7 in the ROM so that upper level character
codes or control codes are output when these keys are closed. The DELETE code is unaffected by these key
switches.
4.5 DATA COMMUNICATIONS INTERFACE
A simplified diagram of the Data Communications Interface is shown in Figure 4-15, Timing is shown in Figure 4-16.
4.5.1 20 rnA Loop Receiver
A simplified diagram of the Loop Receiver is shown in Figure 4-17. Signal line current can be up to 80 rnA. Higher
currents will activate the zener diode, which limits the receiver voltage drop to 1.6 V for currents up to 1 A. Any
current over 15 rnA is interpreted as a mark; any current under 3 rnA is interpreted as a space. Isolation of 1500 V is
provided by the Photo Isolator.
4.5.2 20 rnA Loop Driver
A simplified diagram of the Loop Driver is shown in Figure 4-18.
Isolation of 1500 V is provided by the Photo Isolator. The circuit goes to the MARK state for currents as low as
20 rnA when the MPC is idling or when the LA36 power is turned off. Signal line current must be limited to 80 rnA.
Voltages exceeding 40 V should not be used to drive the loop.
4.6 CLOCK LOGIC
The clock frequencies used to time the Microprogrammed Controller (MPC) are obtained as shown in Figure 4-19.
All frequencies are derived from a Crystal Oscillator and Shaper that generates a 1.6896 MHz square wave. This
signal is divided down by two ripple counters, a -Tt 1 binary counter and a 715 binary counter to produce the
necessary timing signals and baud rate signals. The frequencies and time periods produced are shown in Table 4-4.
Important timing relationships are shown in Figure 4-20.

4-28

XO-XI

Yr/J-YB

STROBE DELAY

I
I
I

DATA READY

------~I~I--------------------------------~~

STROBE

------~Irl--------------------------------~----DATA (BIT l-BIT 71

------~Irl----------------------------~
CP-'615

Figure 4-14 Keyboard Timing Diagram

J3
LINE

PRINTER

I
I

I---~_~

CONNECTS
TO STANDARD
CURRENT
LOOP
INTERFACE

LOCAL_

KEYBOARD

20MA

r-==---I RCVR
LOOP

! : ..

LINE

LOCAL ....

) ~~~~D

rLO~CAL-l

I ACTION OF I
: LlNE/ LOCAL:
L.S~!.T~.H__ ...J

CONNECTORS

_RCV
)
--+XMIT

CONNECTS
TO OPTIONAL
INTERFACE
CP-1163

Figure 4-15 Data Communications Interface Diagram

4-29

~1·~--------looms----------~-1

I I
START
BIT

8
DATA
BI TS

LSB

2
STOP
BITS

110 BAUD

Ir-'-or.1:T~""::;::--:T~....~-:-r-~-.~t,;=t~~=~~::;il~-I
I

I
I

I I

L-~~I_~I~I~~I_~'~I~~I_L-L ~

-I I- 9.09ms

1...>------- 66.6 ms

--------+I_I

I
I I
START
BIT

8
DATA MSB
BITS

LSB

1 I
STOP
BIT

150 BAUD

r-'-oL. . Jr:~': ~:'~:~'~:::'::~:i;: :LI-_T~: ~,~:~:;:L,-'-,~ ,---l

---,I _

-I I-

--'

6.66ms

>-------- 33. 3 ms --------!_~I

11 . . . .

i I

START~LSB
BIT _

r. . ' '

r-'-...

I
I

-I I-

I
I
I

8
DATA
BITS

PARITY

MSB~
~

•

I I
~_ STOP
BIT

300 BAUD

, r-'-..

T ' .... T-r--T
I I
I
,

I
I

1 II
...J

3.33ms
CP·1171

Figure 4-16 Data Communications Interface Timing Diagram

+5V

5.1.
RECEIVE

BREAK/LINE ILOCAL
GATES
MPC5

CP-1580

Figure 4-17 20 rnA Loop Receiver Diagram

4-30

+5
PHOTO

TRANSMIT

ISOLATORA---.l

BREAK/LINEI S.O.
LOCAL GATES - - - - - '

MPC5
CP-1579

Figure 4-18 20 rnA Loop Driver

592n5

+5V

ClK H

ClK l

1. 184ms
+5V

ClK 0
1.6896MHz
CLOCK

RO 1+ 2

RIPPLE
COUNTER
+16
r--- ClKl
R3

-:-2
RO
ClK 0
RIPPLE Rl
COUNTER
-:-4
R2
ClK 1
R3 ,±!I

r±-L

+15
BINARY
COUNTER
MSB
ClK

1.76 KHz

208H
76p.5

19l

'---- ClK

MSB

4.8KHz

+11
BINARY
COUNTER
150p.5

208
CP-1581

Figure 4-19 Oock Logic

4-31

Table 4-4
Clock Frequencies and Time Periods
Frequency

592

1.184p.s

elK

Time Period

1.6896 MHz

592 ns

844 kHz

1.184/1s

844 kHz (CLK)

50 ns pulse/l.184/1s time period

106 kHz

9.4/1s

53kHz

18.8/1s

26.5 kHz

37.7/1s

13.25 kHz

75.5 /1S

4.8 kHz

208.3/1s

2.4 kHz

416.7/1s

1.7 kHz

588.2/1s

., r-

5Ons

L
L

Jl
I.

1.184p.s

CP-1616

Figure 4-20 Clock Timing Relationship

4-32

4.7 UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER (UART)
A simplified diagram of this logic is shown in Figure 4-21. Depending on the operating mode (LOCAL or LINE),
ASCII data is applied to the UART from the Keyboard System or from the Data Communications Interface.
Keyboard data is 7-bit parallel ASCII. Interface data is serial.
Initially, the CLR R DONE flip-flop and the UART are cleared by the WAKE UP pulse from the Wake-up circuit.
During on-line transmission, parallel data from the keyboard are transferred to the UART by KEY STB Hand
converted to serial data, which is applied to the Data Communications Interface. In the LOCAL mode, the serial
output of the UART is gated directly back to the serial input. Consequently, no data is transmitted but a MARK is
sent to indicate that the terminal is not active. Incoming data is locked out by the gating.
In either mode, the serial input data is assembled and converted to parallel data by the UART. Then, the UART
outputs a DA flag to notify the MPC which issues a WRITE BUFF pulse. This pulse sets the CLR R DONE flip-flop.
After the character has been stored in the character buffer, the MPC issues a CLR DA pulse. This pulse clocks the
CLR R DONE flip-flop, which clears R DONE in the UART so that the next character can be processed.
The rate at which characters are transmitted or received by the UART depends on the BAUD RATE that has been
selected by the BAUD RATE switch. Three signals from the Clock Logic are applied to the baud rate
gates: 1.76 kHz, 2.4 kHz and 4.8 kHz. These gates are controlled by the BAUD RATE switch as indicated by the
tru th table (Table 4-5). The selected signal is applied to the clock inputs of the UART.
A BREAK - from the keyboard will interrupt the MARK on the serial output line. This is the serial equivalent of
sending a START bit, followed by a continuous space and no stop bit, which is often interpreted as a Transmission
Interrupt by the receiving device.
4.8 CHARACTER BUFFER/GENERATOR AND PRINT HEAD SYSTEM
A simplified diagram of this logic is shown in Figure 4-22. Characters from the UART are stored in the Character
Buffer RAM (CB RAM). This is a 15 character FIFO memory that is always read-enabled because the ENB input is
grounded. Characters are written into successive locations in the buffer by the WRITE BUFF pulse from DECI.
The Read or Write addresses of the character location are stored in the Character Buffer Address register. Addresses
are clocked to the Character Buffer by LD CBA from DEC 1. Each time a character is written or read, the
corresponding address is incremented by the MPC. As each character is read from the buffer, it is decoded by the
Character Generator ROM (CB ROM), which is a 1024 X 8 ROM that stores a dot matrix pattern in a cell for every
printable character and a unique code for each non-printable control character. Each character cell is defined by a
7 X 7 dot matrix as shown in Figure 4-23. Rows are selected by the ASCII code, A(4:9) and CSO. Subcolumns are
selected by the COLumn INCrement COUNT, A(I :3). The dot matrix is output to the solenoid amplifiers. The first
bit location in each row (subcolumn 0) contains aliOs. All bits in the eighth row are used to identify printable and
non-printable characters. This row contains allIs for printable characters and aliOs for non-printable characters.
There is one multi-stage amplifier for each solenoid. These amplifiers convert the Head Select logic levels (HS} to
HS7) to drive current for the solenoids. The last stage of the amplifier is clamped to +60 V by a zener-controlled
voltage regulator. This reduces the effects of the voltage produced by the inductive load of the solenoid and ensures
that the wires retract completely between subcolumns.
Solenoid current is regulated by the VREF Regulator. This regulator provides a constant current source for uniform
density of character impressions, regardless of resistance and temperature variations.
The dot pattern is synchronized with the position of the print head by the COL INC COUNT as shown in Figure
4-24. The print head solenoids are fired according to the position of the print head. The MPC continuously checks
the Printable Character Indication (PNT ABL H) in MUX } and sends a Head Enable (HD EN) pulse to the amplifiers
when the print head is at a subcolumn boundary. Each time this pulse is received, the appropriate solenoids are fired
and a subcolumn of dots is printed.

4-33

WRITE BUFF

-=
ClR DA l

R
DONE

ClR
R DONE

DEC 1 MPC4

KEY 7

ClR R
DONE
C

KEY 6
KEY 5
KEY 4
KEYBOARD

KEY 3
KEY 2
KEY 1
KEY STB H

XD7

MUX 1
MPC 4

5.0.

XD6
BREAK +

XD5
XD4

DATA
5.0. COMMUNICATIONS
INTERFACE
MPC5

UART

XD3
XD2
XDI
lDXD

WAKE UP W.U.l
MPCB

RDI
RD2
RD3
RD4

5.1.
DATA COMMUNICATIONS
INTERFACE MPC5
+5V

DA H

RD5
5.1.

CB RAM
M PC 6

RD6
RD7

LINE/lOCAL

ClKS

ROB
2SB

CP-I582

Figure 4-21 DART/Mode Selection and Baud Rate Selection Logic

4-34

SET HOE

J.
DEC 1
MPC4

CLR HOE

0
HOE
C

HD EN
(HOE)
MPC8

-21V

BUF HOE EN B

V REF
REGULATOR

WRITE BUFF

UART
MPC6

WR
ENB
M4
DO
01
Ml
02
M2
CHARACTER
03 BUFFER M3
RAM
DO
Ml
01
M2

~
HSI MPC6

A4
A5
A6
A7
AS
A9
CSO

CHARACTER
BUFFER
ADDRESS
REGISTER

DECI LD CBA
MPC4

+21 V

Bl
B2
B3

HS2 MPC6

JL
...
HS3 MPC6

HS4 MPC6

B6
B7

HS6
MPC6

PTBL
L
MPC6

SOL5~

U-L
...

SOL6~

J/
.

SOL7 ~

U-<II!.
.....
~

'---

COL INC COUNT 0

SOL4

J... .....

HS6
MPC6

SOL2~

SOL 3

J/
....

CHARACTER
HS5
GENERATOR
MPC6
ROM
B4

REG { MPC4
-

VREF
SOLI

PNTABL H MUX 1
MPC4

CONTROL
CHARACTER t--=-DECODER ~

COL INC {
COUNTER COL INC COUNT 1
MPC7
COL INC COUNT 2

MUX 2
MPC4

CP-1583

Figure 4-22 Character Buffer/Address Register/Generator and Print Head System

4-35

•

234

ROWS
A[4:9]+CSO
(ASCII CODE) 5

•
•
•
•
•
•
6

SUB COLUMNS
A[I:3]
(COL INC COUNTI
CP-I592

Figure 4-23 CG ROM Character Cell

COL INCREMENTS
CARRY--,

,CARRY

+ ~ , ,

•

I I

•
•

•

21
t"
31
ROWS
(SOLENOIDS)

""'l+

BOUNDARY._ _~~"I
~........._ _ _ CHARACTER
(01" HEAD MOTION) -

•
•
•
•
•

1"- -

r- -

61
1-71

L
9

•

.J
1
---1

•
•

1
--j

•
•

--,

-1

1
---I

•
2

..,

....I

COL INC COUNT
(HEAD POSITION)

HEAD TRAVEL

::>

CHARACTER
SPACING

CP-11I93

Figure 4-24 Print Head Operation

4-36

Dots are never printed in subcolumns 0, 8 and 9. These subcolumns are used for the fixed spacing between
characters. The dot patterns are arranged so that two dots never print in the same row of adjacent subcolumns. This
ensures consistent dot quality and optimizes solenoid power consumption by allowing the solenoids to retract
completely before they are fired again.
When the MPC detects a Non-Printable Indication (PNTABL L) it does not send a HD EN pulse. Instead, the
character is decoded by the Control Character Decoder. Only 4 of the 7 bits from the CG ROM are needed to
identify the four control characters: Backspace (BS), line Feed (LF), Carriage Return (CR) and Bell (BEL). These
codes are applied to MUX 2 and processed by the MPC.
4.9 CARRIAGE SERVO SYSTEM
A block diagram of the Carriage Servo System is shown in Figure 4-25. The speed and direction of the carriage
motor are determined by the speed data from the MPc. This information is stored in the SPEED register. When a
change of speed is required, the appropriate data is generated by the MPC and loaded into the register by LOAD D/ A
L from DECI. The various possible combinations of SPEED commands are shown in the truth table in Table 4-6.
This register is cleared by W.U. L during wake-up (refer to Section 4.12). The speed data in the SPEED register is
applied to the Summing Network together with the output of the + and - TACHs. The sum of these voltages is
amplified and smoothed by the Operational Amplifier and the feedback networks; the result is a dc voltage called
SUM. This voltage is amplified by the Power Amplifier to produce the current required to drive the Carriage Servo
Motor. A positive voltage drives the motor clockwise, moving the carriage forward from left to right. A negative
voltage drives the motor and the carriage in the opposite direction.

REG 1H

SPEED!
DATA
REG
MPC4

-. 9

REG OH

REG 2H

+IS~AMP

SUMMING

SPEED
+

REG 3H

NETWORK

POWER
AMP
.

CARRIAGE
SERVO
MOTOR

>30

+
ENCODER

lOAD
DE C 1 DIA l
MP C4

WAKE UP W. U.l
MPC B

-INC

I FWD

-TACH
ClO CK 761£ sec
lOG IC
MP C5

+INC

[ REV

+TACH

PTl

ENCODER
SIGNAL
DETECTOR
PT2

MUX 1 C H
MPC4
MUX 2 B H
MPC4

MUX 2 INC H
MPC4

COLUMN

DEC 1 ClK HOE l
MPC4

{'"' '.,

COUNTER

r
INCREMENT
HOLD FIF

REV

~ INCREMENT I COUNT

CARRY/BORROWL
GENERATOR

DEC 1 ClR C/B
MPC4

ClOCK
l OGIC
M PC5

PT2

PTl

THRESHOLD
DETECTOR
ANO
FilTER

THRESHOLD
DETECTOR
AND
FilTER

COL INC COUNT
TO CG ROM
MPC6

592ns

ClK H
CP-1584

Figure 4-25 Carriage Servo System

4-37

Table 4-6
MPC SPEED Command Truth Table
Register Information Loaded into D/A
D/A (+ = PRINT, -= RETURN MOTION)
Reg3

Reg2

Regl

(1)

RegO
(1)

Nominal
Speed (ips)

-3.8

-7.6

-11.4

-15.2

-19.0

-22.8

-26.6

-30.4

-34.2

-38.0

-41.8

-45.6

-49.4

4-38

The encoder on the motor shaft generates two feedback signals: PTl and PT2. These signals are applied to the
dual-channel Threshold Detector and Filter, which converts them from sine waves to square waves for processing by
the Encoder Signal Detector which is controlled by the CLK H, 1.184 ms and 592 ns timing signals from the Clock
Logic. The Encoder Signal Detector produces a COUNT pulse and logic level commands for the +TACH and the
-TACH, which are clocked by a 76 J.1S timing signal from the clock logic. The +TACH and -TACH produce 76 J.1S
velocity feedback pulses, which are algebraically combined (summed) with the SPEED command to smoothly
correct the speed and direction of the motor. Increment data is stored in the Increment Hold (INC H) flip-flop. This
flip-flop is cleared by the CLR HDE L pulse from MPC4. Whenever the + or - TACH flip-flop is set, INC H is
clocked; thus providing data for the MPC, which uses it to synchronize the printed dots with the carriage position.
The COUNT pulses produced by the Encoder Signal Detector are counted by the COL INC Counter. The output of
this counter provides column position feedback data for the CG ROM. Counter overflow is stored in the
Carry/Borrow Generator to provide print head position change feedback data for the MPC.
4.9.1 Tachometer, Summing Network and Sum Amplifier
Increment pulses are converted to velocity feedback by the Tachometer Logic shown in Figure 4-26. When an
increment occurs, it is stored in the appropriate TACH flip-flop. The increment data is transferred to the flip-flops
immediately, but the transfer of the TACH pulse to the Summing Network may occur anywhere from 0 to 76 J.1S
later, depending on the occurrence of the data with relation to the clock signal.
The second positive transition of the 76 J.1S clock signal clears the TACH flip-flops, thus prOviding a 76 p.s pulse to
the Summing Network for each increment. The TACH flip-flops are inhibited on the first increment following a
direction reversal to keep the print head from oscillating.

PTl
WINDOW

r--

,..L

F/F
,.--- f--C

PT2
CLOCK

F/F
C

DIR
HOLD
F/F
01-

---, .--

THRESHOLD
DETECTOR
MPC7
-0

r---

TACH
C Of--

TACH

T
-

'-- 0

.047UF

r-~T

232K
SUMMING
NETWORK

r--0

TACH

:.r1

POWER
~~
AMP
....

TACH
O-rf-C
"---

CL OCK
LO GIC
MP

,:I

SPEED
DATA R
MPC4

7614sec

REG OH
REG lH
REG 2H

SPEED
REGISTER

REG 3H

+
+
+
CP-1585

Figure 4-26 Tachometer Logic

4-39

The TACH pulses are algebraically combined with the SPEED command voltage in the Summing Network. This
network contains precision 1% resistors that produce weighted voltages from both the TACH pulses and the SPEED
commands. The TACH pulses are of opposite polarity from the SPEED command voltages. Consequently, the
feedback pulses oppose (buck) the SPEED commands. The sum of the two voltages is amplified by the Sum
Amplifier and fed back to the negative input of the amplifier via the active Low Pass Filter to smooth the TACH
pulses. The result is an average dc voltage (SUM) which produces feedback that exactly counter-balances the SPEED
commands.
4.9.2 Encoder and Threshold Detector
The Encoder circuit and mechanism are illustrated in Figure 4-27. The light sources from two light-emitting diodes
(LEDs) are focused on a slotted disk that is mounted on the motor shaft in front of a slotted mask and two
infrared-sensing phototransistors. Rotation of the disk creates an interference pattern that causes the
phototransistors to generate two sine waves, PTl and PT2. These sine waves are always 90° out of phase as shown in
Figure 4-27. When the disk rotates in the forward direction PT1leads PT2 by 90°. PTl and PT2 are applied to two
Threshold Detectors. PTl and PT2 are approximately 0.5 to 1 V POp centered around a threshold of approximately
4.5 V. When the signal is above the threshold, the output is -0.7 V and when the signal is below the threshold the
output is 3.9 V. These signals are filtered by an RC circuit and shaped into square waves by Schmitt triggers. The
Schmitt triggers logically invert the output of the Threshold Detectors, thus providing a logic high for encoder levels
above the threshold and a logic low for encoder levels below the threshold.
4.9.3 Encoder Signal Detector
The Encoder Signal Detector contains four flip-flops: +, -, DIR HOLD and COUNT. A simplified diagram for this
logic is shown in Figure 4-28. Incremental changes are detected by using PTl as a window and PT2 as a clock as
shown in Figure 4-29. Encoder square wave PTl is applied to the data inputs of the + and - flip-flops and PT2 is
applied to the clock inputs.
The + flip-flop is set by positive-going edges that occur during positive windows and the - flip-flop is set by
negative-going pulses that occur during positive windows. Direction reversals are latched by the DIR HOLD flip-flop.
When either the + or - flip-flop is set, increment data is stored in the COUNT flip-flop. At time state Tl, this
flip-flop is clocked by the negative-going edge of the 1.184 ps pulse as shown in Figure 4-30. At time state T2 the
COUNT pulse is gated to the COL INC Counter by CLK H.
At time state T3, the + and - flip-flops are cleared by the positive-going edge of the 592 ns pulse in order to process
succeeding increments.
4.9.4 Column Increment Counter and Carry/Borrow Generator
A Simplified diagram for this logic is shown in Figure 4-31; timing is shown in Figure 4-30. When either the + orflip-flop in the Encoder Signal Detector is set, increment data is stored in the COUNT flip-flop. At time state T2, the
COUNT pulse is gated to the Column Increment (COL INC) Counter by CLK H. The negative-going edge of the
COUNT pulse clocks the counter.
The COL INC Counter is a BCD counter which counts up if the COUNT pulses result from a positive increment and
down if they result from a negative increment. Overflow from the counter is stored in the OVERFLOW flip-flop and
gated to the SIGN and Carry/Borrow (C/B) flip-flops. At time state Tl, the OVERFLOW flip-flop is cleared by the
1.184 fJ.S pulse from MPC5. At time state T2, the OVERFLOW flip-flop is set by the OVERFLOW increment. At
time state T3, the OVERFLOW pulse is gated to the SIGN flip-flop and the CIB flip-flop by the 592 ns pulse.

4-40

+5V-r------,

PT 2 tt-..;--\--+---\---/---\-

J~
DISK

o 90·
FWD-PTI LEADS PT2 BY 90·

+
+ 5 V-'VIII~r-'"1

PTI OR
PT2
ENCODER
SIGNAL
DETECTOR
MPC7

">---'V""~~--i SCHMIDT
TRIGGER

MASK

PTI

PT2

REV - PT2 LEADS PTI BY 90·

SLOTTED DISK
CP-,59,

Figure 4-27 Encoder and Threshold Detector

~-----------_

PTI WINDOW

, _ _ _ _ _'-'-"'-'--_ _ _ _ _ } TO
r
REV

+ TACH

DIR

+
C

FROM

HOLD

FWD

I----'--"-' ----}

THRESHOLD
DETECTOR
MPC7

-TACH

FROM -TACH
D
PT 2
CLOCK

CLOCK LOGIC
MPC5

COL INC
COUNT COUNTER AND
INC HOLD
MPC7

592 ns
CLK H
CP-'586

Figure 4-28 Encoder Signal Detector

4-41

DIRECTION
REVERSAL
PTt (WINDOW)

PT2 (CLOCK)

DIR HOLD F/F

+ TACH

t
t

TACH

CP-1617

Figure 4-29 Increment Detection Timing

This toggles the C/B flip-flop to indicate that an overflow occurred. If the counter has just reached 9, the SIGN
flip-flop is set to a 1 and a BORROW H is sent to the MPC. If the counter has just reached 0, the SIGN flip-flop is set
to a and a CARRY H is sent to the MPC. The C/B and SIGN flip-flops are sampled by the MPC every 416 p.s and the
CjB flip-flop is retoggled by CLR C/B after each sample is taken.
The CLR INIT command is issued by the MPC at the end of the INIT routine to set the COL INC Counter to 5 and
clear the C/B flip-flop.
4.10 BELL SYSTEM
A simplified logic diagram of the Bell System is shown in Figure 4-32. Initially, the BELL HOLD flip-flop is cleared
by W.D. from the wake-up circuit. When a bell is required, the BELL HOLD flip-flop is set by a SET BELL pulse
from the DEC1. This gates a 2.4 kHz signal (208H) to the speaker via a transistor switch, (Q10) to produce an
audible tone. The MPC controls the duration of the tone, by clocking the BELL HOLD flip-flop with the CLR BELL
pulse at 100 ms intervals.
When the MPC is initialized or the print head passes the 132nd column, the KB HOLD flip-flop is set by a CLR KBH
L pulse from DECI. Each time a character is shifted into the DART, the KB HOLD flip-flop is clocked by EOC (End
Of Character). When the print head passes the 64th column, the MPC checks KBH. If it is set, the MPC sends a SET
BEL pulse to the BELL HOLD flip-flop.

442

592 ns

1.1841'1

MPC5~

ClK H

IJl

I
+ F/F

I
TIl
- F/F

I
I

II
T3i

T21

I
I
I
COUNT FI F

I
I
COUNT PULSE

I
I

OVERFLOW F/F

I
I

Lr-

OVERFLOW PULSE

C/B

F/F

....-------11 1-1- - - - - - - - - - ,
SIGN F/F

ClR

\~\------------~LJ

C/B l

CP-1618

Figure 4-30 Encoder Signal Detector and Column Increment Counter Timing Diagram

4-43

CLK

MPC7

COLUMN R2 COUNT 2
INCREMENT
COL INC
COUNTER RI COUNT I
ON
COL INC
RO COUNT 0

+F/F +INC
MPC7

BORROW H MUX 1
MUX 2
MPC 4

R3I-C-O-L-IN-C------------1 0

COUNT FI F COUNT

SIGN
C

} CG ROM
MPC6

CARRY H MUX I
MPC4

LD
CLR
DEC I INIT L
MPC4

o
1. 184 p.5ec

CLOCK{
LOGIC
MPC5

CIB

OVERFLOW

CLR CIB
DEC 1 {
MPC4 CLR INIT L

L -_ _ _ _~

592n5
CP-1587

Figure 4-31 Column Increment Counter and CIB Generator Logic

SPEAKER
SET BELL

DECI
MPC4

0
CLR BELL

BELL
HOLD
C

WAKE UP W.U.
MPC8
CLOCK LOGIC 208H
MPC5
CLR KBH
DECI MPC4

-=
UART
MPC6

EOC

KB
HOLD
0
C

KBH MUX 1 MPC4
CP-1589

Figure 4-32 Bell System Logic

4-44

4.11 LINE FEED STEPPER SYSTEM
A simplified logic diagram of the Line Feed Stepper System is shown in Figure 4-33.
Four STEP commands and a HOLD command are issued by the MPC when a line feed is required. The STEP LF L
command pulses are applied to the clock -inputs of a Grey Code Counter and to the data input of the LF HOLD
flip-flop. The SET HOLD L command pulse is applied to clear inputs of the counter and the set input of the LF
HOLD flip-flop.
The relationship of these pulses is shown in Figure 4-34. At power up, W.u. sets the LF HOLD flip-flop, causing the
LF amplifiers and the LF HOLD amplifier to apply a holding current to both phases of the LF stepping motor. W.u.
also clears the counter.
When a line feed command sequence is issued by the MPC, the LF HOLD flip-flop is reset and the STEP LF pulses
are decoded by the counter as shown in the truth table in Table 4-7. The LF HOLD, LFI and LF2 amplifiers are
turned on and off accordingly. Each change causes the stepping motor to advance 15°, providing four steps for each
line advance and vertical spacing of 6 lines per inch. A complete line advance takes 33 ms ±5% nominal.
After the line advance is completed, another SET HOLD pulse is sent by the MPC and the LF HOLD flip-flop is set
again. A 10 ms delay (typical) between line feeds allows the stepping motor to settle. The minimum settling time is
S.2ms.
4.12 WAKE-UP CIRCUIT
The Wake-Up Circuit is shown on MPCS. This circuit is a time-delayed transistor switch that generates a 700 ms W.U.
pulse. The W.U. pulse initializes the MPC logic before the MPC starts to run. W.U. pulse duration is dependent on the
RC time constant of the resistor and capacitor across the +5 V power supply. During power up, the output transistor
is turned on and W.u. is at logic level zero. Mter one time constant (approximately 700 ms), the output transistor is
turned off, W.U. goes to logic level one and the MPC starts to run.
4.13 POWER SUPPLY AND REGULATOR
A block diagram of the Power Supply circuits is shown in Figure 4-35. The ac line voltage is stepped down by a
transformer, rectified and filtered to produce +21 V, -21 Vand +5 V.
These voltages are regulated to produce +12 V ±5%, -12 V ±5%, +5 V ±5% and - 9 V ±5%.
4.14 PRINTER MECHANISM
The LA36 is an incremental impact printer that uses a 7-wire solenoid-activated print head which moves horizontally
and prints characters in a 7 X 7 dot matrix. A fixed print bar is impacted by pressure on an inked ribbon traveling
between the horizontally-moving print head and the paper. Figure 4-36 illustrates the printing principle used in the
LA36. Seven individually selectable solenoids are mounted in a cluster on the Print Head Assembly. The armatures
of the solenoids are fitted with long wires that function as the printing element by impacting the inked ribbon
against the paper.
Each printed character is inscribed by positioning the print head at seven discrete horizontal positions as it traverses
the paper. For each of the seven horizontal positions, a combination of solenoids is activated to produce a 7 X 7 dot
image of the selected character.
The printer mechanism of the LA36 is made up of several functional subsystems: the Carriage Subsystem, the
Ribbon Feed Subsystem, and the Paper Feed Subsystem.

4-45

PHASE 1

STEP LF L

D
1
GREY
CODE
COUNTER
1
C

-20
+20
PHASE 2

LF2

LF STEPPING
MOTOR

-20
DEC 1
MPC4

LF
HOLD

LF
HOLD
S

SET HOLD
WAKE UP W. U.
MPC8

COMMON

-=
CP-1588

Figure 4-33 line Feed Stepper System

STEP LF L

SET HOLD L

LF HOLD L

23 MS

-I-

J
J

to MS--l

I
I

LFt H

1
I

LF2 H

I
I

I 5.0
I MS

I-

II
6.8

7.5
MS

3.7
MS

33 MS

NOTE:
Not drawn to scale.
cp- 1619

Figure 4-34 line Feed Timing Diagram

4-46

Table 4-7
LF Pulse Truth Table
LF2

LFI

Hold

Step LF

+21VDC

+12V
VOLTAGE
REGULATOR

-AC
LINE

~
POWER
ON/OFF

LINE
FILTER

BRIDGE
RECTIFIER
AND
FILTER

-12V
VOLTAGE
REGULATOR

+12VDC

Y -"

-12VDC

VOLTAGE
REGULATOR

STEP DOWN
~ TRANSFORMER

-9VDC

-21VDC

BRIDGE
RECTIFIER
AND
FILTER

+5V
VOLTAGE
REGULATOR

+5VDC

CP-I590

Figure 4-35 Power Supply Block Diagram

4.14.1 Carriage Subsystem
The Carriage Subsystem (Figure 4-37) includes the print head and the carriage which ride on the two support shafts
that extend the full width of the printer mechanism. The carriage is driven by a timing belt which is held captive
between the print head and the carriage and runs on a pulley at each end. The right-hand pulley is mounted on the
dc servo motor, which provides the driving power for the carriage. The left-hand pulley is mounted on the ribbon
drive shaft and transmits power to the Ribbon Feed Subsystem.
The carriage supports and positions the print head relative to the print bar and provides for adjustment of the paper
gap by means of a detented adjustment lever on the right side of the carriage. Each detent position represents
approximately 0.003 inch of gap and allows for a total of approximately 0.020 inch of paper gap.

447

CP-1171

Figure 4-36 LA36 Printing Principle

ECCENTRIC

DRIVE SHAFT

ADJUSTMENT

QPULLEY
1/5 PITCH
TIMING BELT

CP-1172

Figure 4-37 Carriage Subsystem

4-48

4.14.2 Ribbon Feed Subsystem
The Ribbon Feed Subsystem (Figure 4-38) consists of a ribbon drive and a ribbon reversal mechanism. The left-hand
pulley, attached to the ribbon drive shaft, drives the ribbon feed through a one-way clutch/eccentric, a pushrod, and
a ratchet/pawl mechanism_ The one-way clutch allows for ribbon feed during the printing cycle and inhibits feed
during the carriage return cycle. A brake on the one-way clutch allows the eccentric to turn in one direction only.
The eccentric on the ribbon drive shaft translates rotary motion to linear motion and drives the ratchet/pawl by
means of a pushrod. The ratchet/pawl mechanism translates linear motion to the rotary motion required to turn the
ribbon reels. The main pawl and the upper pawls, due to their unique arrangement, alternately perform drive and
backlash functions, depending upon the direction in which the pushrod is traveling. When shifted to the left or to
the right by the rivet at the ends of the ribbon, the reverse sensor cams an interposer into the path of the tab on the
main pawl. The blocking action of the interposer and the pivoting action of the ratchet base assembly shift the main
pawl and engages the upper pawl in the opposite ratchet wheel.
Ribbon reversal is accomplished by carriage motion rather than by ribbon motion. This eliminates the possibility of
carriage stalls due to excessive tension during the reversing action.
Constant ribbon tension is maintained by a friction disk on each ribbon reel.

BACKSTOP
SPRING

ECCENTRIC

PUSH ROO

MAIN
PAWL

REVERSE
SENSOR

RATCHET

INTERPOSER
BAIL CAMMING
FOLLOWERS

PAWL

CP-1175

Figure 4-38 Ribbon Feed Subsystem

449

4.14.3 Paper Feed Subsystem
The Paper Feed Subsystem (Figure 4-39) includes a stepping motor, a manual clutch, and two pin-fed tractors.
The stepping motor connects to the tractors through a 2:5 gear train and a square drive shaft. The driven gear on the
square shaft is fitted with a manual clutch that uncouples the gear train from the square shaft when the line feed
knob is axially depressed. This allows fine vertical adjustments when preprinted forms are used.
The stepping motor executes four steps for each line advance to ensure that the tractors will always initialize on an
integral line when the machine is turned on.
The use of tractors permits flat surface feeding which eliminates interleaf slippage in multi-part forms and reduces
hole distortion during paper feeding.

15° STEPPING MOTOR
2:5 GEARTRAIN

SQUARE
DRIVE SHAFT
ADJUSTABLE PINFEED
TRACTOR
ADJUSTING KNOB

MANUAL
CLUTCH

CP-I173

Figure 4-39 Paper Feed Subsystem

4-50

CHAPTER 5
ELECTRICAL SERVICING

5.1 ELECTRICAL TESTS
The test equipment required for the electrical tests is listed in Table 5-1. Equivalent test equipment may be
substituted. Two kinds of tests are provided: off-line and on-line. No diagnostics are required to perform these tests.
No waveforms are provided for the MPC section of the Logic Board because special test equipment is required for
accurate measurement and interpretation. Theoretical timing data and program descriptions are provided in Chapter
4. All measurements are dc-coupled and referenced to ground unless otherwise stated. Waveforms are idealized.
VOLTS/DN setting applies to both Channell and Channel 2 unless otherwise stated.
5.1.1 Off-Line Tests
The Off-Line Tests provide a means of obtaining test data in a stand·alone mode. All tests are performed with the
LINE/LOCAL switch set to LOCAL and the BAUD RATE switch set to 110.
Remove the protective housing from the LA36 as directed in Section 5.2.1, Steps 1 and 2; lower the rear access door
before performing any Off-Line Tests.
5.1.1.1 Encoder Signal Processing Test - The Encoder Signal Processing Test checks the open loop operation of the
Threshold Detectors, Encoder Signal Detector, and the +/- TACH in the Carriage Servo System using test voltages to
drive the servo motor.
NOTE
The Current Limiting Resistor shown in the test setup
diagrams can be omitted, but caution should be exercised to
prevent damage.
To check the circuits that drive the motor in the positive direction, perform Steps 1-6; to check the circuits that
drive the motor in the negative direction, perform Steps 7-9.
NOTE
The voltages and time periods in the Carriage Servo System
vary for different machines and line voltages. The values listed
in Figures 5-3 - 5-12 are nominal and can only be used as
troubleshooting guides.
1.

Set the POWER ON/OFF switch to OFF.

Slip the drive belt from the pulley on the motor shaft. Release the tension on the timing belt by pressing
the spring-loaded ribbon drive assembly.

5-1

Table 5-1
Test Equipment and Special Tools
Equipment

Manufacturer

Multimeter

Triplett or Simpson

Model 630 NA or 620

Oscilloscope

Tektronix

Type 454 (or equivalent)

IC Clip

A.P. Inc.

24 pin DEC No. 29-19556
16 pin DEC No. 29-10246

XIO Probe

Tektronix

P 6010 (or equivalent)

Slip-on-Tip

Tektronix

013-0090-00 (or equivalent)

EZHook

Pomona Electronic

3925 (or equivalent)

Designation

Resistor

30 to son, 10 W min.

Resistor

1000n, 1/4 W min.

Remove the servo fuse (F 1) from the Power Board.

Connect +21 V to the motor as shown in Figure 5-1.
CAUTION
Power Board damage may result if the test voltage is
connected improperly in Step 4.

Set POWER ON/OFF switch to ON. The motor should rotate in the positive direction (clockwise as
viewed from the front of the LA36).

Check the waveforms at the test points shown in Figures 5-3 - 5-8.

Set POWER ON/OFF switch to OFF and connect 21 Vto the motor as shown in Figure 5-2.

Repeat Step 5. The motor should rotate in the negative direction (counterclockwise).

Check the waveforms at the test points shown in Figures 5-11 - 5-12.

10.

Disconnect the test setup and reinstall the drive belt and the servo fuse (Fl).

5-2

RESISTOR AND JUMPER
WITH ALLIGATOR CLIPS

POWER BOARD
30-50 OHMS
10 W MIN

~
~
PHYSICAL CONNECTION

J4
,-MOTOR

8
v

+21 V

30- 50 OHMS
10 W MIN

L---

ELECTRICAL CONNECTION

CP-1604

Figure 5-1 Encoder +21 V Test Setup

RESISTOR AND JUMPER
WITH ALLIGATOR CLIPS

POWER BOARD

30 -50 OHMS
10 W MIN

PHYSICAL CONNECTION

MOTOR

-21V

30- 50 OHMS
10 W MIN

............

L.-.-

ELECTRICAL CONNECTION
CP-1605

Figure 5-2 Encoder -21 V Test Setup

5-3

5.1.1.2 Servo Speed Test - The Servo Speed Test checks the closed loop operation of the Servo Amplifier, Sum
Amplifier, Summing Network, and Column Increment Counter in the Carriage Servo System in the Initialize mode.
To check the negative feedback logic and the Carry/Borrow Logic, perform Steps 1-4. The motor runs in reverse at
a speed of 6 in./sec. To check the positive feedback logic and the Carry/Borrow Generator, perform Steps 1-3 and
Steps 5 and 6. The motor runs forward at a speed of 6 in./sec.
1.

Set the ON/OFF switch to OFF.

Push the left drive pulley to the right to release the tension on the drive belt; slip the belt from the right

drive pulley.
3.

Set the ON/OFF switch to ON.

Check the waveforms at the test points indicated in Figures 5-13 - 5-20.

Jumper the base of Q3 to ground. This causes the servo motor to reverse direction and run at 6 in./sec.

Check the waveforms at the test points indicated in Figures 5-21 - 5-26.
NOTE
Voltages and time periods in the Carriage Servo System vary
for different machines and line voltages. The values listed in
Figures 5-13 - 5-20 are nominal and can only be used as
troubleshooting guides.

Reinstall the drive belt and remove the jumper from the base of Q3.

5.1.1.3 LF Stepping Test - This test causes the LF stepping motor to run continuously. It generates signals to test
the Grey Code Counter, both channels of the amplifier and the LF HOLD circuit.
1.

Press the LF key and the REPEAT key at the same time to get a sequence of line feeds.

Check the waveforms at the test points shown in Figures 5-27 through 5-33.

5.1.1.4 Bell Test - This test drives the Bell System logic, providing the signals required to trace the circuit.
1.

Hold down the CTRL key and press the BELL key and the REPEAT key.

Check the waveforms at the test points indicated in Figures 5-34 and 5-35.
NOTE
Voltage measurements at J5-2 taken with WI jumper inserted.

Press the RETURN and REPEAT keys and check the waveforms at the test points indicated in 5-36.

5.1.1.5 Printable Character Test - This test checks the operation of the Printer Logic in the LOCAL mode. Various
printing characters are used to provide test data that can be easily interpreted. The / (slash) character generates a
single dot in each column. The U and * characters generate complementary ASCII codes that test every bit on the
lines between the keyboard, the UART, the Character Buffer and the CG ROM. Sixteen characters are used to create
a buffer full condition.
1.

Press the / (slash) key and the REPEAT key to get a series of printing characters that have one dot in
every column.

Check the waveforms at the test points listed in Figures 5-37 - 547.

Press the SHIFT LOCK key and strike the U key 16 times to fill the Character Buffer. Check the test
points for the U character, one at a time as follows:
Test Point
M7722

Character
U
*

Test Point
M7722

Character
U
*

E55-26 and E56-4

E28-18

E55-27 and E56-6

E28-17

E55-28 and E56-10

E28-16

E55-29 and E56-12

E28-15

E55-30 and E60-4

E28-14

E55-31 and E60-6

E28-13

E55-32 and E60-10

E28-12

Press the SHIFT LOCK key and strike the * key 16 times to fIll the Character Buffer. Check the test
points for the * character one at a time as shown above.

5.1.1.6 Clock Test - The Clock Test checks all clock frequencies and time periods in the Initialize mode.
1.

Set the ON/OFF switch to ON.

Check the waveforms at the test points indicated in Figures 548 - 5-55.

5.1.2 On-Line Tests
The On-Line Tests provide a means of obtaining test data in a simulated on-line mode. All tests are performed with
the LINE/LOCAL switch set to LINE. Remove the protective housing from the LA36 as directed in Section 5.2.1,
Steps 1 and 2 and lower the rear access door before performing any On-Line Tests,
5.1.2.1 Current Loop Interface - The Current Loop Interface Test checks the operation of the 20 rnA current
loops (transmit and receive) for the standard configuration. On-line operation is simulated by connecting the
transmit and receive loops back-to-back through a Current Limiting Resistor.
1.

Set the ON/OFF switch to OFF.

Connect the transmit and receive loops back-to-back as shown in Figure 5·56.

Set the POWER ON/OFF switch to ON.

Set the BAUD RATE switch to 300.

5-5

Press the SHIFT LOCK key, the) (close parenthesis) key and the REPEAT key to get a series of printing
characters that have one dot in every row.

Check the waveforms at the test points listed in Figures 5-57 - 5-58.

Press the SHWT LOCK key; hold down the U key and the REPEAT key and check the test points for
the character U, one at a time.

Character

Test Point
M7722

E28-18

E55-27 and E56-6

E28-17

E55-28 and E56-10

E28-16

E55-29 and E56-12

E28-15

E55-30 and E60-4

E28-14

E55-31 and E60-6

E28-13

E55-32 and E60-IO

E28-12

Test Point
M7722

E55-26 and E56-4

Character

Press. the SHIFT LOCK key; hold down the * key; the REPEAT key and check the test points for the *
character, one at a time.

Check the frequency at M7722 E55-,-40 for each position of the BAUD RATE switch:
Position

Frequency

300

4.8 kHz

150

2.4 kHz

110

1.76 kHz

The time periods should be the same as the corresponding"Clock Logic signals (Figures 5-53 and 5-54).
5.1.2.2 Serial Line Interface - The Serial tine Interface Test checks the operation of the serial input and serial
output and mode selection logic for the standard configuration. On-line operation is simulated by connecting the
transmit and receive logic back-to-back through a jumper.
1.

Set the ON/OFF switch to OFF.

Connect the transmit and receive loops back-to-back as shown in Figure 5-59.

5-6

Set the POWER ON/OFF switch to ON.

Set the BAUD RATE switch to 300.

Press the SHIFT LOCK key and the) (close parenthesis) key and the REPEAT key to get a series of
printing characters that have one dot in every row.

Check the waveforms at the test points listed in Figure 5-60.

Press the SHIFT LOCK key; hold down the U key and the REPEAT key and check the test pOints for
the character U, one at a time.

Character
U
*

Test Point
M7722

Character
U
*

E55-26 and E56-4

E28-18

E55-27 and E56-6

E28-17

E55-28 and E56-10

E28-16

E55-29 and E56-12

E28-15

E55-30 and E60-4

E28-14

E55-31 and E60-6

E28-13

E55-32 and E60-10

E28-12

Test Point
M7722

Press the SHIFT LOCK key; hold down the * key; the REPEAT key and check the test points for the *
character, one at a time.

5.1.3 Troubleshooting Charts
The Troubleshooting Chart in Table 5-2 lists the common trouble symptoms that could be observed during
installation checkout or during normal operation of the LA36. If no symptom is given with the machine servicing
request, perform the installation checkout procedure in Section 2.5 to determine the status of the machine. This
procedure and the Troubleshooting Chart are cross-referenced to aid in diagnosing problems. Appropriate paragraphs
and figures in this manual are referenced to provide additional information needed to isolate defective components
and realign, adjust, or replace assemblies. Replaceable assemblies are: Printer Mechanism, Print Head, Keyboard,
Numeric Pad, Logic Board and Power Board. (Chassis-mounted parts are also replaceable.)
The MPC section of the Logic Board is not listed as a probable cause because it is quite difficult to field test this
section correctly without special test equipment. Replace the Logic Board whenever an MPC fault is suspected. Do
not attempt to replace components on the Logic Board, Power Board, or Keyboard.
Check all fuses and power supply voltages before beginning to troubleshoot. Fuse locations are shown in the
lllustrated Parts Breakdown (Chapter 8). Power supply voltages are shown in Table 5-3 and in Figures 5-61 and 5-62.
Voltage measurements are referenced to ground unless otherwise indicated.

5-7

START OF ENCODER SIGNAL PROCESSING TEST WAVEFORMS

SCOPE SETUP

r- PT2

T7
L

PT1

\)JI7SV~.....1)~ ~ v.J ~ I[l
.....
r-

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

VARIABLEAPPROX.
75 Its/DIV

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC,
INT, POS

-'-...!

4.5 VDC

GND

VOLTS/DIV:

CH1 to +PT1 at Power Board J4-5
CH2 to +PT2 at Power Board J4-G
CP-1636

Figure 5-3 +PTI and +PT2 Waveforms

SCOPE SETUP

4VI

--4V

GND

,-I-.

900 LEAD_

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

10 ItS

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

GND
CH1 to +PT1 at M7722 TP1 IEG-8)
CH2 to +PT2 at M7722 TP2 lEG-G)

CP-1637

Figure 54 +PTI and +PT2 Schmidt Waveforms

5-9

+ INC MAY OCCUR
ANYWHERE DURING ~----'--r--"T"""-""'-"""'---'----'
THIS TIME

4 VI

~~~~~~~=~==1==JITTER

_-+_--+_--1

GND
COUNT F/F MAY SET
ANYTIME FROM 0 TO -++l-+1H-+++++f+t++++f+t++++-I-+-If++++++~
1.184 fJ.S AFTER + INC
~~i-__~__~__~__~~COUNTF/FCLEARED
4VI

592 NS LATER

SCOPE SETUP
VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

500 ns

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, INT, POS

CH1 to +INC at M7722 E8-9
CH2 to COUNT at M7722 E4-9

GND

CP-1638

Figure 5-5 +INC and COUNT Flip-Flop Waveforms

3.8

SCOPE SETUP

1.184 f.lS

GND

,_-.!

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

200 ns

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, INT, POS

l"'""-

3.8 V I
f-

CH1 to COUNT F/F at M7722 E4-9

ttt-

GND
-t

~ I- ~o NS

CH2 to COUNT Pulse at M7722 E29-8
tt-

I-

CP-1639

Figure 5-6 COUNT Flip-Flop and COUNT Pulse Waveforms

5-10

3.9

1.184 IJS

SCOPE SETUP

GND

,--,

3.9

'--'

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

200 n5

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, INT, POS

CHl to COUNT F/F at M7722 E4-9
GND
CH2 to CLR +/- F/F at M7722 E9-6

340NS

I
CP-1640

Figure 5-7 COUNT Flip-Flop and CLR ± Flip-Flop Waveforms

118.4 1-'5

SCOPE SETUP

GND

VERTICAL MODE:

AL T

HORIZ DISPLAY:

"'--761-'5

TlME/DIV:

I_~

JITTER

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, INT, POS

CHl to +INC at M7722 E8-9

ffGND

VOL TS/DIV:

CH2 to +TACH at M7722 Qll-C

rrCP-1641

Figure 5-8 +INC and +TACH Waveforms

5-11

SCOPE SETUP
VOL TS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

VARIABLE~

APPROX.
75 IlS
TRIG MODE:

NORMAL

TRIG SOURCE:

CH1,AC,
INT,POS

CH1 to PT1 at Power Board J4-5
CH2 to PT2 at Power Board J4-6
CP-1642

Figure 5-9 - PTl and - PI2 Waveforms

4VI

SCOPE SETUP

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

10,us

TRIG SOURCE:

CH1, AC, POS,INT

GND
,--;

J I

'- ...!

4VI

.-- 90° LAG

CH1 to -PT1 at M7722 TP1 IE6·8)
CH2 to -PT2 at M7722 TP2 IE6·6)

GND

CP-1643

Figure 5-10 -PI1 and -PI2 Schmidt Waveforms

5-12

-INC MAY OCCUR
ANYWHERE DURING
THIS TIME

SCOPE SETUP
VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

COUNT F/F MAY SET

TIME/DIV:

500 ns

AN Y TIME FROM 0 TO I+-I,-++++f-+jf+-l++++-l-+-If+-I++++-I-+-I++++-l-+-I-+++-l
1.184/.15 AFTER -INC

TRIG MODE:

NORMAL

t-----T--r---+--!---f--t- COUNT F/F CLEARED

TRIG SOURCE:

CH1, AC, INT, POS

4VI

JITTER
~!-----+----I---~

GND

592 NS LATER

CH1 to -INC at M7722 E8-5
CH2 to COUNT at M7722 E4-9

GND

CP-1644

Figure 5-11 - INC and COUNT Flip-Flop Waveforms

3.SV

GND

I H
-.-

SCOPE SETUP

118.4 /.IS
VOLTS/DIV:

CH1=2 V; CH2=5 V

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

20/.15

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, INT, POS

~76/.1s
f-

of-,
L

- r-. JITTER -

CH1 to -INC at M7722 ES-5

GND - ' - -

CH2 to -TACH at M7722 Q12-C

CP-1645

Figure 5-12 - INC and -TACH Waveforms

END OF ENCODER SIGNAL PROCESSING TEST WAVEFORMS

5-13

START OF SERVO SPEED TEST WAVEFORMS

SCOPE SETUP

4 VI

INC MAY OCCUR
H\o'~Io'h':P'>"A ANYWHERE IN
~%oW>~i!--+---+-----i
THIS REGION

GND

VOLTS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TlME/DIV:

10/ols

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

CH1 to INC at M7722 ES-9
CH2 to 76 /oIS CLOCK at M7722 ES-11
2/o1s
..
CP-1646

Figure 5-13 -INC and 76 JlS CLOCK Waveforms

SCOPE SETUP

1.5 V::Z::=

.VI

IL
II

J
-I

76j.1S

GND

,-,
!.._,

,.
I I

VOLTS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

10/ols

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1,AC,
POS,INT

.8V
76,/oIS

CH1 to TACH at M7722 012·8

CH2 to TACH at M7722 012-C
CP-1647

Figure 5-14 -TACH Waveforms at Q12-B and Q12-C

5-15

761'S

SCOPE SETUP

GND

VOLTS/DIV:

VERTICAL MODE:

ALT

lI-

HORIZ DISPLAY:

TIME/DIV:

101'5

TRIG MODE:

NORMAL

lI-

TRIG SOURCE:

CH1. AC. POS.INT

CH1 to -TACH at M7722 E5-5

,-h
'-f-!

4VI

GND

CH2 to 76 1'5 at M7722 E5-3

iii-

CP-1648

Figure 5-15 -TACH and 76 JlS Waveforms

-1.3MS

1.5 V
GND
GND

j.- r- 76 1'5

SCOPE SETUP

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

2001'5

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC. POS, INT

:i-'

:
/
r-r-lr
-5V

VOL TS/DIV:

--- =--r-1-0..

/ r--..... .............

CH1 to -TACH at M7722 Q12-B
CH2 to SUM at M7722 J1-8 (E1-6)

CP-1649

Figure 5-16 -TACH Waveform and SUM Waveform at J1-B

5-16

SCOPE SETUP

II-

1.5V

I n

GND

GNDI

1.3'MS_

_l-h

I I

CH1=2 V; CH2=5 V

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

500 IlS

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

'-f-!

I/""

-3V

j.- 761'5

VOLTS/DIV:

/ ' ~~

/" ~

v--..
~

CH1 to -TACH at M7722 Q12-8
CH2 to MD at Power Board J4-8

CP-1650

Figure 5-17 - TACH and MD Waveforms

4VI

SCOPE SETUP

416 MS

GND
'--'

VOL TS/DIV:

VERTICAL MODE:

CH 1

HORIZ DISPLAY:

TIME/DIV:

50 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG, INT

CH1 to INC at M7722 E30·9

CP-1651

Figure 5-18 INC Waveform

5-17

I-

~MS,

SCOPE SETUP

I-

GND

1-'

VOLTS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

T1ME/DIV:

2ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1. AC. POS.INT

'-...!

-r--

CH1 to COL INC COUNT (MSB) at
M7722 E16-7
GND - ' - -

1~S

CH2 to COL INC COUNT 2 at
M7722 E16-6

CP-1652

Figure 5-19 COL INC COUNT 3 (MSB) and COL INC COUNT 2 Waveforms

-1

j4r-3MS

4VI
GND

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

5ms

TRIG MODE:

NORMAL

Il-

TRIG SOURCE:

CH1. AC. POS.INT

I-

CH1 to COL INC COUNT 3 (MSB) at
M7722 E16-7

30MS

CH2 to BORROW Hat M7722 E12-3

I-

4VI

SCOPE SETUP

,-h
'-f-J

I-

GND

CP-1653

Figure 5-20 COL INC COUNT 3 (MSB) and BORROW H Waveforms

5-18

SCOPE SETUP
4 VI

INC MAY OCCUR
~~~~~ANYWHEREIN

VOLTS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

10 Its

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS,INT

~~~~g---~---+--~

THIS REGION
GND

CH1 to +INC at M7722 E3-9
CH2 to -76 Its CLOCK at M7722 E3-11

CP-1646

Figure 5-21 +INC and 76 J1S Waveforms

76 ItS

4VI

SCOPE SETUP

VOLTS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

10 Its

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS,INT

GND

.h
q--'

:.:r

CH1 to +TACH at M7722 E3-5
CH2 to 76 ItS at M7722 E3-3

CP-1654

Figure 5-22 +TACH and 76 p.s Waveforms

5-19

SCOPE SETUP

I-I--

76~s

1.5 V

=+=

GNO

,--,

VOL TS/DIV:

CH1=5 V;
CH2=5 V

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

10~

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1,AC,
POS,INT

'--'

9VI

CH1 to +TACH at M7722 011-8

.8V
76 ~s

CH2 to +TACH at M7722 011-C

CP-1655

Figure 5-23 +TACH Waveforms at QII-B and QII-C,

SCOPE SETUP

1.3MS

- ..
5VI ----- --

1.5VI

-76~

,-,_ .J-;

I--

,..- ~

GND

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

200~s

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1,AC,POS,INT

~
CH1 to +TACH at M7722 011-8

CH2 to SUM at J1-8 (E1-6)
CP-1656

Figure 5-24 +TACH and SUM Waveforms

5-20

SCOPE SETUP

1SVI'n

VOLTS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

500/J.s

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1.AC.POS.INT

11--1.3MS I--

GND

1 17

-t

I- 76

jJS

I'--V

GND

r
n-,

f'- V

i'- V

Vil

CH1 to +TACH at M7722 Q11-B
CH2 to MD at J4-8

CP-1657

Figure 5-25 +TACH and MD Waveforms

SCOPE SETUP

4VI

GND

,--,
'-fJ

4VI

VOLTS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TlME/DIV:

5ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1. AC. POS.INT

CH1 to COL INC COUNT 3 (MSB) at
M7722 E16-7

GND

CH2 to CARRY Hat M7722 E7-6

CP-1658

Figure 5-26 COL INC COUNT 3 (MSB) and CARRY H Waveforms

END OF SERVO SPEED TEST WAVEFORMS

5-21

START OF LF STEPPING TEST WAVEFORMS

+21±

23MS

:-....

III I:

GND

SCOPE SETUP

-21 ± 5 V

.11

20V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5ms

TRIG MODE:

NORMAL

I-

TRIG SOURCE:

CH1, AC, NEG, INT

CH1 to PHASE 1 at Power Board J5·7

I -_

VOLTS/DIV:

I -

I-

k~ h

i '- ~'
~-

+21 ± 5 V I

...........

GND

---

-21 ± 5 V

I -

I
L_ ~
I

CH2 to PHASE 2 at Power Board J5·6

II -

7.5
MS

CP·1659

Figure 5-27 LF Motor Phase 1 and Phase 2 Waveforms

21±5V

GND

I
I

I
I
I
I

I
I

6.8

7 Ji

20 V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

.LL

,_...!

I 5.0 I

:'I 1,-II

I
lit

VOL TS/DIV:

I I

21± 5V
GND

SCOPE SETUP

I -

I
I
I

CH1 to LF1 at Power Board TPA12 (034-C)
CH2 to LF2 at Power Board TPA15 (036-C)

13 •7 1

~23MS~
CP-1661

Figure 5-28 LFI Waveform at TPA12 and LF2 Waveform at TPA15

5-23

SCOPE SETUP

GNDI

I
I

-21 V ± 5 V

I
I
I
I

I -

I-

I I

I
I

I
GNDI
-21 V ± 5 V

I ,I

20V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC,
POS,INT

I:
I~h

I~f-:T

CH1 to LF1 at Power Board
TPA13 (Q35-C)

VOLTS/DIV:

CH2 to LF2 at Power Board
TPA16 (Q37-C)

1
MS
MS
MS
~17~

3 ,7
MS

23MS
CP-1662

Figure 5-29 LFI Waveform at TPA13 and LF2 Waveform at TPA16

5V-r-

0.6V~

5VI
0.6 V

I
I
I
I
I
I

I
I
I

.O I
I
~
MS

6.8
MS

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

I t-t-

TIME/DIV:

5 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG,INT

I t-j:
I
II

tt-

CH1 to LF1 at Power Board TPA14 (Q39-C)

I fI ,-~
'-j-!

VOL TS/DIV:

I
I
I

I
I

SCOPE SETUP

I
3 •7
~.5
.1 MS
MS
:1

CH2 to LF2 at Power Board TPA 17 (Q38-CI

23MS
CP-1663

Figure 5-30 LFI Waveform at TPA14 and LF2 Waveform at TPA17

5-24

122M~

21± 5V

SCOPE SETUP
VOL TS/DIV:

CH1=20 V;
CH2=2 V/DIV

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

I r-,

TIME/DIV:

5 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG, INT

GND

I
I !..-'

1VI

GND

CHl to LF Motor Common Return at
Power Board J5-4

22MS

CH2 to LF HOLD at Power Board
Jl-29 (033-B)
CP1664

Figure 5-31

LF Motor Common Return and LF HOLD Waveforms

rr-

2VI

GND

ii,

I I,-h

I
Ii

I
I
I

ii'

II'

2VI
GND

I'-~

I
t

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS,INT

CHl to LFl at M7722 Jl-JJ (E29-9)

I
I

CH2 to LF2 at M7722 Jl-P (E24-5)

.Ol
I ~5
1
~
MS

6.S
MS

VOLTS/DIV:

I
I
I r-

SCOPE SETUP

rr-

3 .7
MS

23MS

CP-1666

Figure 5-32 LF1 Waveform at 11-11 and LF2 Waveform at 11-P

5-25

GND

SCOPE SETUP

I
~15MS

i
I

rr-,

VOL TS/DIV:

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1. AC. POS.INT

3.8 V

CH1 to LF1 at M7722 E24-9
GND

CH2 to LF HOLD at M7722 E29-6
22MS
CP-1665

Figure 5-33 LFI Waveform at E24-9 and LF HOLD Waveform at E29-6

END OF LF STEPPING TEST WAVEFORMS

5-26

START OF BELL TEST WAVEFORMS

416j1.S

3VI

SCOPE SETUP

GND

,-,
-'

5VI

...

GND

416 j.lS

VOLTS/DIV:

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

100j.ls

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1,AC, NEG,INT

CH1 to BELL Source at Power Board J5·1
CH2 to BELL SINK at Power Board J5·2
CP-1668

Figure 5·34 BELL Source and BELL SINK Waveforms

r
5V

106MS
BURST

SCOPE SETUP

416 j.lS
PERIOD
GND _ I - -

,-,
!.._,

VOLTS/DIV:

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

20ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS,INT

CH1 to BELL SINK at Power Board J5·1

GND

106M~

106MS
I

CH2 to BEL at M7722 E36-5

CP·1667

Figure 5·35 BELL SINK and BEL Waveforms

5·27

SCOPE SETUP

4VI
GND

VOL TS/DIV:

VERT MODE:

CH1

HORIZ DISPLAY:

TIME/DIV:

20 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

Io..w..i; h

84MS~

'-I-'
j4--16 MS
~
I-

CH1 to KBH Hat M7122 E51-8

CP-1669

Figure 5-36 KBH H Pulse Waveform

END OF BELL TEST WA VEFORMS

5-28

START OF PRINTABLE CHARACTER TEST WAVEFORMS

SCOPE SETUP
600 JJ.s
I-

4VI
GND
,-I-,
~I-'

+20Vf

60V

I-

OV
-20V

1oI~1------ 600 JJ.s - - - - -...-11

VOLTS/DIV:

CH1=2 V; CH2=20 V

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

100 JJ.s

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG, INT

CH1 to HD EN at Power Board J1-4 (R5S)
CH2 to SOL 1 - SOL7 at Power Board J6
pins K2, N2, 02, 62, T2, F2 or S2 (017-C,
019-C, 01-C, 020-C, O1S-C, 016-C or
021-C)

CP-1670

Figure 5-37 HD EN and SOL Waveforms at J6

4VI

SCOPE SETUP

VARIES WITH
MOTOR SPEED

GND

'-I-..!

VOL TS/DIV:

CH1=2 V; CH2=5 V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

500 JJ.s

TRIG MODE:

HF REJECT

TRIG SOURCE:

CH1, AC, NEG, INT

CH1 to HS1 - HS7 at Power Board J1 (right side
of R31,R49, R7, R2S, R42, R15,and R35)

4VT V- 21V

-L

-f

I----

CH2 to SD1 - SD7 at test points V, R2 BZ, 0,
K or AS
600 JJ.S
CP-1671

Figure 5-38 HSI and SDI Waveforms at TPP

5-29

SCOPE SETUP

VARIES WITH
MOTOR SPEED

4VI
GND

,--,
!.._,

VOL TS/DIV:

CH1=2 V; CH2=5 V;
AC-COUPLED

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

500j.ls

TRIG MODE:

HF REJECT

TRIG SOURCE:

CH1, AC, NEG, INT

CH1 to HS1 - HS7 at Power Board J1 (right side
5V,
- 21V

--J

"""

of R49, R7, R28, R42, R21, R15 and R35)
CH2 to SD1 - SD7 at test points A3, 0, Z, T, N,

~6ooj.lS

or A7
CP-1672

Figure 5-39 HSI and SDl Waveforms at TPN

GND

SCOPE SETUP

VARIES WITH
MOTOR SPEED

~:--

,- -;

VOLTS/DIV:

CH1=2 V; CH2=10 V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

500 j.lS

TRIG MODE:

HF REJECT

TRIG SOURCE:

CH1, AC, NEG,INT

,_ -J

CH1 to HS1 - HS7 at Power Board J1 (right side
-21 V,-'"-~

of R21, R49, R7, R28, R42, R15 and R35)

f4- 600j.lS

CH2 to SD1 - SD7 at test points A1, B, W, R, L,

For A5
CP-1673

Figure 540 HSI and SDl Waveforms at TPL

5-30

SCOPE SETUP

VARIES WITH
MoioR SPEED

4VI

lI-

VOL TS/DIV:

CH1=2 V; CH2=10 V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

500/.1.5

TRIG MODE:

HF REJECT

TRIG SOURCE:

CH1. AC. NEG. INT

GND

h
\...1-'

GNDI

20V

----

CH1 to HS1 - HS7 at Power Board J1 (right side
of R21. R49. R7. R2S. R42. R15.and R35)

~600/.l.s

:
:

CH2 to SD1 - SD7 at test points M. A2. R3 (right
side). Y. S. H. or A6
CP-1674

Figure 5-41 HS1 and SDl Waveforms at TPM

SCOPE SETUP

5VI
GND

-l

4vI

I
T

GND

\.- 600 j.lS

VOL TS/DIV:

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1. AC. NEG. INT

CH1 to HD EN at J1 (R5S) (E39.s)

INDICATES A DOT IN
SUBCOLUMN ONE ONLY.

CH2 to HS1 - HS7 at Power Board J1 (right side

PULSE SHIFTS FOR
DOTS IN DIFFERENT
SUBCOLUMNS (SE E
FIGURE 5-43)

of R21. R49. R7. R2S. R42. R 15. and R35)

CP-1675

Figure 5-42 HD EN and HS7 Waveforms at 11 (R35)

5-31

5VI

GND

I- 600

SCOPE SETUP

or.

ILS

VOL TS/DIV:

VERTICAL MODE:

CHOP

HORtz DISPLAY:

TIME/DIV:

2ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG,INT

\...1-'

4VI

INDICATES A DOT IN
SUBCOLUMN TWO ONLY.

GND

..I...

CH1 to HD EN at J1-D (R58) (E39-8)

CH2 to HS1 - HS7 at Power Board J1 (right

PULSE SHIFTS FOR
DOTS IN DIFFERENT
SUBCOLUMNS (SEE
FIGURE 5-42)

side of R21, R49, R7, R28, R42, R 15 and R35)

CP·1676

Figure 543 HD EN and HS6 Waveforms at J1 (R15)

5 V -.--

r--

I"'"

r-r-

SCOPE SETUP

,
GNDI - I . - -

rr.
:,-,

I 11tn nJ 1J1

VOL TS/DIV:

CH1=2 V; CH2=5 V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5ms

TRIG MODE:

NORMAL

TR IG SOURCE:

CH1,AC, NEG,INT

GND

CH1 to HD EN at J1 (R58)
CH2 to BUFF HEAD EN H at TPA

CP·1677

Figure 544 HD EN and BUFF HEAD EN H Waveforms

5·32

SCOPE SETUP

4VI

r-600IlS--i
VOL TS/DIV:

CH1=2 V AC-COUPLED;
CH2=1 V

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

,-h

TIME/DIV:

200 IlS

I-

TRIG MODE:

NORMAL

II-

TRIG SOURCE:

CH1, AC, POS, INT

I-

GND
I-

T '/
~ .V

'-f-!

3 AMPS

"-I'--;

1-0..
l-

CAUTION

I-

Float scope power line before making

these connections.
CP-1678

CH1 to HD EN at M7722 E39-9
CH2 to SD1 - SD7 at R52, R53, R1, R54, R56,
R51,R55
Probe ground on -21 V

Figure 5-45 HD EN Voltage Waveform and SD Current Waveform

SCOPE SETUP
-

,-,

4VI

GND

'--'

- 50 NS

--4

VOLTS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

200 ns

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG, INT

CH1 to WRITE BUFF L at E60-10
GND

Ii
I

1.2 IlS

CH2 to CLR R DONE at E60-8
II

CP-1679

Figure 5-46 WRITE BUFF Land CLR R DONE Waveforms

5-33

~
SCOPE SETUP

5VI

VOL TS/DIV:

VERTICAL MODE:

CH1

HORIZ DISPLAY:

TIME/DIV:

200 ns

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG,INT

d-,

GND

!..~'

500 NS- ~

CH1 to KEY STB L at M7722 E67-4

CP-1680

Figure 5-47

KEY STB L Waveform

END OF PRINTABLE CHARACTER TEST WAVEFORMS

5-34

START OF CLOCK TEST WAVEFORMS

GND
-I

:
:
:

VOL TS/DIV:

VERTICAL MODE:

AlT

HORIZ t>ISPLAY:

TIME/DIV:

200 ns

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

I---

50 NS

it-.
1.184J.i.S

G::I

SCOPE SETUP
~

CH1 to ClK H at M1722 E64-5
CH2 to 592 ns at M1722 E64-10

....-592J.i.S~

I
CP-1681

Figure 5-48 eLK Hand 592 ns Waveforms

I- 592 NS--tI

SCOPE SETUP
ff-

G::1

VOlTS/DIV:

VERTICAL MODE:

AlT

ff-

HORIZ DISPLAY:

TIME/DIV:

200J.i.s

lI-

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

lII-

CH1 to 1.184 J.i.S at M7122 E13-1

I-~'

4VI

I-I-!
1=
f-

GND
CH2 to 592 ns at M7122 E13-14

1.184 J.i.S
CP-1682

Figure 5-49 592 ns and 1.184 JiS Waveforms

5-35

76).15

SCOPE SETUP

1-.
lI-

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

10,us

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1,AC, POS,INT

Il-

GND

I-

,-I-

'-~

4VI

I-

CHUo 76,us at M7722 E26-11
GND

CH2 to 9.4,us at M7722 E26-1

I1----=::.4,uS I
CP-1683

Figure 5-50 76 flS and 9.4 f.1S Waveforms

4VI

18.8,us

SCOPE SETUP

GND

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

,-I-;
'-l-f

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS,INT

CH1 to 19L at M7722 E26-9

~
~ l-

VOL TS/DIV:

9.4,us

CH2 to 9.4 ,us at M7722 E26-1

I
CP-1684

Figure 5-51 19 Land 9.4 flS Waveforms

5-36

761'5

SCOPE SETUP

GND

it-I
~'

4VI
GND

VOL TS/DIV:

2 V

VERTICAL MODE:

ALT

HORIZ DISPLAY:

TIME/DIV:

10 Its

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

C-

---

I--

--- ---

....

1\4-18.~ 1t5~

I--

-I-

""""

-"-

----

CHl to 76 ItS at M1722 E26-11
CH2 to 18.8 ItS at M1722 E26-9

CP·1685

Figure 5-52 76 llS and 18.8 llS Waveforms

208 itS

150 ItS

SCOPE SETUP

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

20 ItS

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

f:
irl

4VI
GND

- - -

--l

0-'

- - - -

I-

~I-- 18.8115

CHl to 4.8 kHz at M1722 E63-11
CH2 to 18.8 /-LS at M7722 E26-9

=+=
CP·1686

Figure 5-53 4.8 kHz and 18.8 llS Waveforms

5-37

416/lS

4VI

SCOPE SETUP

GND
;-1-,

'-f-'

.......

4VI

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TIME/DIV:

50 !-IS

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

CH1 to 20SH at M7722 E26-12

GND

VOL TS/DIV:

• ~r-150 /lS--"
20S /lS I

5S /lS ~
I

CH2 to 4.S kHz at M7722 E63-11

l
CP-1687

Figure 5-54 208 Hand 4.8 kHz Waveforms

56S/ls

4VI

SCOPE SETUP

GND

r-,
-'

4VI

VOL TS/DIV:

VERTICAL MODE:

AL T

HORIZ DISPLAY:

TlME/DIV:

100/lS

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, pas, INT

CH1 to 1.76 kHz at M7722 E68-11
GND'

CH2 to 37.6 /lS at M7722 E26-S
I--- 37.6 /lS

CP-1688

Figure 5-55 1.76 kHz and 37.6 fJ,S Waveforms

END OF CLOCK TEST WAVEFORMS

5-38

ST ART OF CURRENT LOOP INTERFACE WA VEFORMS

~~~BO~----------------l

I
I

l~r~T~:I

1tt JU~PER

(

L_~-

~ ~ ~

I
I

\~~~~

CJUMPER USING MATE-N-LOK PINS
______
___
~_~~

~~_~~~

PHYSICAL CONNECTION

M7722
20 MA

LOOP

J4
7

1000 OHM
1/4 WATT

-12V--~-<~~----~V0~-----'~>-r-------

20 MA

+12V--~~~~---------------.~o-+-------

ELECTRICAL CONNECTION
CP-1606

Figure 5-56 Current Loop Test Setup

5-39

SCOPE SETUP

SVI

r--

GND

1.SV

1--

GND

.........

VOL TS/DIV:

CH1=2 V DC.cOUPLING;
CH2=1 V AC.cOUPLING

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

Sms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

CH1 to S.I. at M7722 J4·2 (EG2·1)

..-

'--

f--

CH2 to RECEIVE at M7722 J3·3

I-

NOTE: MARK = GND; SPACE = S V or 1.S V
CP-1689

Figure 5·57 Loop Receiver Waveforms

SVI
GND

1.SVI

GND

SCOPE SETUP

..,.,..

T"T"'I

TT"

VOL TS/DIV:

CH1=2 V DC.cOUPLlNG;
CH2=1 V AC.cOUPLING

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

Sms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, NEG, INT

- -

r--

CH1 to S.O. at M7722 EGG·11

CH2 to TRANSMIT at M7722 J3-5

NOTE: MARK = GROUND; SPACE = S Vor 1.S V
CP-1690

Figure 5·58 Loop Driver Waveforms

END OF CURRENT LOOP INTERFACE WAVEFORMS

5-40

START OF SERIAL LINE INTERFACE WAVEFORMS

,---------------~
LOGIC BOARD

I
I
I
I

M7722

I
l

,I
I

YUMPER

'---..__ ........ __ ------- ........ --------- ....... ---- ............ ...J
PHYSICAL CONNECTION

M7772

J4
2

S.l.

S.O.

JUMPER

ELECTRICAL CONNECTION
CP·1623

Figure 5-59 Serial Line Test Setup

5VI

r-~

~t-'

r-l-

VOL TS/DIV:

VERTICAL MODE:

CHOP

HORIZ DISPLAY:

TIME/DIV:

5 ms

TRIG MODE:

NORMAL

TRIG SOURCE:

CH1, AC, POS, INT

l.r:b.

GND

1~vI

SCOPE SETUP

r--

CH1 to S.O. at M7722 E29-12
GND
CH2 to S.1. at M7733 E66·6

NOTE: 5 V = SPACE; GND = MARK
CP-1691

Figure 5-60 Serial Output and Serial Input Waveforms

[

END OF SERIAL LINE INTERFACE WAVEFORMS

541

Table 5-2
Troubleshooting Chart
Problem Area

Symptom
l.

No response (Fan
not operating)

Probable Cause

Action

Reference

Main Printer Power Fuse

Blown

Unplug printer. Check FI (2 A
Slo Blo @ 125 Vor I A Slo BIo
@ 250 V). Replace.

Power Harness

Poor connections

Unplug printer, check, correct.

Voltage Jumper 13
(110 V vs 220 V)

Not plugged in or loose

Check, correct, or trace harness.

Power Transformer

Open winding

Unplug printer. Check voltages.

Table 5-3
Section 6.1.16

Fan

Mechanical interference

Check free movement.

Section 6.1.15

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
2.

Print head does
not initialize;
carriage moves
violently or
erratically
from margin-tomargin or goes
to either margin
and stays there.

Problem Area
Logic Board

Power Board

Encoder

Probable Cause

Action

Reference

Loss of clock signals.

Check 592 ns at E64-10

Figure 5-48

Loss of speed control feedback.

Perform Encoder Signal Processing
Test and check:

Sections 5.1.1.1 and
6.1.13

a. Encoder

PT1 and PT2 at J4-5 and J4-6

Figures 5-3 or 5-9

b. Threshold Detector

PT1 and PT2 at TP1 (E6-8) and
TP2 (E6-6)
If signal is present but misadjusted,
adjust Encoder.

Figures 54 or 5-10
Section 6.1.6

c. Encoder Signal Detector

+INC at E8-9 and COUNT F /F
at E4-9 or
-INC at E7-5 and COUNT F/F
at E13-9

Figure 5-5
or
Figure 5-11

d. +/-TACH

+INC at E8-9 and +TACH at Q11-C
or
-INC at E8-5 and -TACH at Q12-C

Figure 5-8
or
Figure 5-12

Encoder Motor fuse blown

Check F1(2ASB)

Failure in servo amplifier

Perform Encoder Signal Processing
Test and check:

Sections 5.1.1.1 and
6.1.14

MD at F1 (R71 side)

saturated + direction -21 ± 5 V
- direction +21 ± 5 V

SUM at JI-B (El-6)

saturated + direction -10 V
- direction +10 V

Replace motor and Encoder if the
Encoder cannot be adjusted.

Section 6.1.6

Defective

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
3.

No line feed, but
bell operates

Problem Area

Probable Cause

Action

Reference

Paper

Paper jammed/feed holes torn

Check paper alignment

Section 3.2.1

Tractors

Not feeding - worn or broken
pin, or out of alignment

Check, align, or replace

Section 6.1.11

Shafts

Binding

Check, align, or replace

Sections 6.2.2 and
6.2.3

Clutch

Binding, broken

Check, align, or replace

Section 6.2.6

Gears

Broken teeth, insufficient
backlash

Check, adjust, or replace

Sections 6.1.10 and
6.2.14

Motor

Open cable or winding

Perform Line Feed Stepping Test
and check signals from Power
Board:

Sections 5.1.1.3,
6.1.12, and 5.1.13

Phase 1 at J5-7
Phase 2 at J5-6

Figure 5-27

Power Board

LF Motor fuses blown

Check F2 and F3 (lASB)

Amplifier output signals missing

Perform Line Feed Stepping Test
and check:

Sections 5.1.1 .3 and
6.1.14

LFI at TPA12 and LF2 at TPA15

Figure 5-28

LFI at TPA13 and LF2 at TPA16

Figure 5-29

LFI at TP14 and LF2 at TP17

Figure 5-30

LF HOLD at J54 and LF MOTOR
COMMON at 11-29

Figure 5-31

LF HOLD switch signals missing

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
3.

(continued)

Problem Area
Logic Board

Probable Cause

Action

Grey Code Counter output missing

Perform Line Feed Stepping Test
and check:

Section $.1.1.3
and 6.1.13

LF 1 at H-JJ and LF2 at H-P

Figure 5-32

LFI at E24-9 and LF HOLD at
E29-6

Figure 5-33

LF HOLD flip-flop output missing

Reference

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
4.

No bell tone,
but line feed
operates

No bell tone
at 64th print
position

Problem Area

Probable Cause

Action

Reference

Loudspeaker

Open voice coil

Remove BEL lead and ground it.
Cone should click. If not, check
continuity and replace speaker.

Wiring

Open or loose

Check security of wiring and correct.

Power Board

Resistor or +5 V

Check and correct.

Logic Board

BELL HOLD flip-flop E36

Perform Bell Test and check:

Sections 5.1.1.4 and
6.1.13

BEL SOURCE at J5-1 and BEL
SINK at J5-2

Figure 5-34

BEL SINK at J5-2 and BEL at
E36-5

Figure 5-35

208 L at E40-10

Figure 5-53

KBH at E51-8

Figure 5-36

KB HOLD flip-flop E51

Table 5-2 (Cont)
Troubleshooting Chart

Reference

Symptom

Problem Area

Probable Cause

Action

Print head
initializes and
bell and line
feed both
operate, but
printer hangs
up on a printable character,
i.e., the print
head does not
move and
character will
not print.

Carriage shaft, drive belt
or pulleys

Binding. Fl (2A Slo Blo) will blow

Set POWER switch to OFF and
move carriage manually. If
binding occurs, check tolerance.

Section 6.1.8

Logic Board

PNT ABL H logic level missing

Set POWER switch to ON. Perform
Printing Character Test and check:

Sections 5.1.2.5 and
6.1.13

PNT ABL H at E33-11

+4V

ASCII codes at E55-26, E56
and E28.

Section 5.1.2.5,
Step 3

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
6.

Printable
characters
replaced by
spaces, but
line feed
operates.

Problem Area

Probable Cause

Logic Board

Power Board

Action

Reference

Perform Printable Character Test
and check:

Sections 5.1.1.5
and 6.1.13

HDE flip-flop E39

HD EN at JI-D (R58)
HDE at E39-8

Figure 543

Buffer Q22

Perform Printable Character Test
and check:

Sections 5.1.1.5
and 6.1.14

HD EN at JI4 (R58) and
BUFF HEAD EN H at T.P.A.

Figure 544

V REF at T.P. B3

2.6 V ±1 %with
respect to -21 V
-5.1 V ± 5 V

V REF current regulator

V REF at T.P. B

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
7.

Missing dots
(always same
row) (all printable characters
that use the
missing row)

Problem Area
Print Head

Probable Cause

Logic Board

Reference

Power down and up. Retry. If
condition exists, let it run. If
condition does not clear, check
the following before replacing
head:
Check winding.

Section 6.1.1

Perform Printing Character Test
and check SOLI-SOL7 at appropriate pin on J6 while printing.
Check appropriate test points in
Drive Amplifier for that row.

Sections 5.1.1.5 and
6.1.14

No head select signals for missing
row

Check HSI L-HS7 L at appropriate pin on Il.

Figures 5-38 and 544

No head select signals for missing
row

Check HSI L-HS7 L at appropriate pin on J1.

Figures 5-42 and 5-43

Failed head select drivers

Check HSI H-HS7 Hat appropriate pins on E20 and E25.

Figures 542 and 543
(inverted)

Stuck or broken impact wire

Open solenoid winding
Power Board

Action

No solenoid drive signals for
missing row

Figure 5-63

Figures 5-38-544

Note
If missing at this point
indicates that bit is missing in the CGROM output.
(always same
row, same
letters)

Logic Board

CG ROM E28 and E33

Replace Logic Board

Section 6.1.13

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
8.

No print, no
space, but
(LF/BEL
operate).

Problem Area
Logic Board

Probable Cause
Loss of printable bit.

Action
Check PNTABL at E2S-10.

Reference
PNTABL H = +4 V
PNTABL L = 0.8 V

Table 5-2 (Cont)
Troubleshooting Chart
Symptom

Occasional to
constant overprint or bunching of characters
in a line or misplaced dots within
a character

Problem Area

Action

Probable Cause

Reference

Carriage

Binding on shafts

Check and adjust

Section 6.l.8

Power Board

Sluggish motor due to defective servo amplifier

Perform Servo Speed Test and
check:

Sections 5.1.1.2 and
6.1.l4

SUM at 11-2

Figure 5-16

MD at J4-8

Figure 5-17

Encoder

Out of adjustment

See Symptom 2

Table 5-2 (Cont)
Troubleshooting Chart
Symptom

10.

Printer stops in
middle of line

Problem Area
Power Board

Probable Cause

Action

Reference

Servo Fuse Fl blown

Check, determine the following
causes before replacing fuse:

Ribbon mechanism jammed
near end of ribbon

Check, adjust, replace

Section 6.1.7

Carriage binding on poorly
adjusted carriage shafts

Check, align, or replace

Section 6.1.8

Broken timing belt

Replace

Section 6.1.2

Timing belt off pulley

Check and correct. Replace
belt if worn or frayed.

Section 6.1.2

Table 5-2 (Cont)
Troubleshooting Chart
Symptom

Problem Area

II. Printer operates

Interface or interface
connectors

Connection problem

Check connectors

Logic Board (in current
loop operation)

Improper jumpers on current
loop converters

Check, correct

Section 2.4 step 9
6.1.13

Failure in isolator circuits

Perform Current Loop Interface
Test and check:

Section 5.1.2.1

S. I. at E62-1

Figure 5-57

S.O. at E66-11

Figure 5-58

in LOCAL but
not ON-LINE

Probable Cause

Action

Reference

TRANSMIT at 13-5
LINE/LOCAL switch

Switch shorted to LOCAL
condition

Check, replace

(In ErA operation or
option)

Failure in gating logic

Perform Serial Line Interface
Test and check:

Section 5 ..1.2.2

S. O. at E29-12

Figure 5-60

S. I. at E66-6

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
12.

Lost characters
after 16 characters have
printed in a
line following
a carriage
return

Problem Area

Probable Cause

Action

Reference

Printer Mechanism

Binding of carriage or shafts is
causing extended carriage
return time

Check and adjust

Sections 6.1.5 and
6.1.8

Logic Board

Incorrect SPEED commands

Perform Servo Speed Test and
check:

Sections 5.1.2.2 and
6.1.13

-TACH at QI2-B and SUM at JI-B

Figure 5-16

+TACH at Qll-B and SUM at JI-B

Figure 5-24

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
13.

Incorrect characters printed
or no backspace
during ON-LINE
operation

Problem Area

Probable Cause

Action

Reference

Logic Board

Missing or added data bits

Perform Printable Character Test
and check ASCII codes at the
listed test points

Section 5.1.1.5,
Steps 3 and 4 and
Section 6.1.13

Keyboard

Same as above

Perform Printable Character Test
and check ASCII codes at E55-26,
27,28,29,30,31 and 32

Section 5.1.1.5,
Steps 3 and 4.
Section 6.1.3 and
6.1.4

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
14.

Problem Area

Action

Probable Cause

Reference

Uneven print
density across
the page

Print Bar

Out of adjustment

Check, adjust

Section 6.1.8

Printing light
in areas

Print Bar

Pitted

Replace

Section 6.2.1

Printing density
progressively
drops off to no
impressions

Ribbon Feed Assembly

Out of adjustment

Check and adjust

Section 6.1.7

Bad Drive Clutch

Repair or replace

Section 6.2.9

Broken backstop spring

Replace

Section 6.2.10

Print Head

Out of adjustment

Check and adjust

Section 6.1.1

Left Tractor

Out of adjustment

Check and adjust

Section 6.1.11

Ribbon feed does not
reverse or feed

Broken ratchet tooth

Replace ratchet wheel

Section 6.2.13

Push rod disengaged

Correct

Interposer adjustment incorrect

Adjust

Section 6.1.7

Out of adjustment

Check and adjust

Section 6.1.11

Paper path not clear

Check and clear

Phase adjustment

Check and adjust

On Tab printing

Ribbon does
not reverse

Paper jams

Tractors

Section 6.1.11

Table 5-2 (Cont)
Troubleshooting Chart
Symptom
15.

Margin drift
(line-to-line
loss of carriage
position)

Problem Area
Encoder

Logic Board

Power Board

Probable Cause

Action

Reference

Out of adjustment or marginal

Perform Encoder Signal Processing
Test and check:

Sections 5.1.1.1 and
5.2.6

PTI at TPI (E6-8)
PT2 at TP2 (E6-6)

Figures 54 and 5-10

If signal is present but misadjusted,
adjust Encoder. Replace motor and
Encoder if Encoder cannot be
adjusted.

Section 6.1.6

Defective connector

Check cable to 11

Loss of SUM amplifier feedback

Perform Servo Speed Test and check: Sections 5.1.2.1 and
6.1.13
Figures 5-16 and 5-24
SUM at JI-B

Defective connector

Check cables to JI and 14

Loss of servo amplifier linearity

Perform Servo Speed Test and
test and check:

Sections 5.1.2.1 and
6.1.14

MD at 14-8

Figures 5-17 and 5-2 5

Table 5-3
DC Supply Voltages
Line Voltage

TP20

J1-3

J1-35

TP20

TPB3

TP21

Normal

+12

-12

-21

-21 Ref
(Vref)

+21

0.9 to 2.4 A

125 Vac

+4.9

+11.6

-11.7

-25.6

-23.0

+25.6

1 to 1.6 A

115 Vac

+4.9

+11.6

-11.7

-23.6

-21.1

+23.6

1.2 to 1.6 A

105 Vac

+4.9

+11.6

-11.7

-21.5

-19.0

+21.5

0.9 to 1.8 A

100 Vac

0.8 to 1.8 A

95 Vac

+4.9

+11.6

-11.7

-19.2

-16.7

+19.9

0.8 to 1.7 A

90 Vac

+4.9

+11.6

-11.7

-17.9

-15.4

+19.9

Line Current

+I2V

050

R99
3.9K

069
RI03
150&1

RI02
619n

G!V

CI5
0.01,.1

CI!D

048

<:IE::>
071
5.IV

R90
270n

CI6
25"f

R92
487n

C§:>
R90
270&1

072
5.IV

R93
487&1

~
045

GlD

CI3
.01,,1
R95
390n

R94
3.9K

GE:>+

046

R98
619n

C§:-IOV

1---

CI8
25"f

R97
150

070

~----~--------~----~==~------L-------~.-12V

051

~--------~~==~~--------~ +5V

+8.5 TO
+13.5V

C8
190"f

CP-1381

Figure 5·61 Typical Voltages for Power Supply Regulators

5·60

T~
-5.1V

R62
100.0.

039
5.IV

J_____

R61
10K

-4.5V

_____ 1

1-----+-1

1 - - - - - 0 TPB3

024

R39
196.0.
R63

R64

R119
121.0.

R120 R121 V
560.0. UK
0

2V-3V
DEPENDING ON
WHETHER R120
OR R121 ARE
CUT OUT

023

-21V--~--~--------L------L--~----~--~---1----~---L--~

@
NOTE:
R120, R121, or both may
be removed in test.

OUTPUT VOLTAGE (VO) OF DIVIDER
IN
OUT
R120
IN
OUT
R12 I
IN
OUT
IN
OUT
2.04
VO
1.82
1.93
2.16
CP-1380

Figure 5-62 Typical Voltages for VRef Supply

NOTE:
Print head shown on bottom view.

Figure 5-63 Print Head Solenoid Resistance Measurement

5-61

CHAPTER 6
MECHANICAL SERVICING

6.1 REMOVAL, REPLACEMENT, AND ADJUSTMENT PROCEDURES
This section contains information pertaining to the removal, replacement and adjustment of the mechanical
assemblies of the LA36. Section 5.3 covers the disassembly, assembly and adjustment of the component parts of the
LA36.
All mechanical assemblies and component parts of the LA36, except the following, may be repaired in the field:
1.

Print Head Assembly

DC Motor and Encoder Assembly

Tractor Assemblies

Ribbon Drive Assembly

Ribbon Chassis Assembly

Carriage Assembly

6.1.1 Print Head Assembly

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and the ribbon.

Open the rear access door on the cabinet.

Disconnect the ribbon cable connector from J6 on the Power Board (Figure 6-2).

Pull the ribbon cable from under the Power Board and up through the slot at the rear of the cabinet.

Remove the 4 (4-40) screws and kep nuts that secure the two ribbon cable clamps to the cabinet base
(Figure 6-3).

Remove the 4 (6-32) screws, lockwashers and flat washers that secure the print head to the carriage and
remove the print head and the ribbon cable (Figure 6-4).

6-1

Secure the new print head to the carriage with the 4 (6-32) screws, lockwashers and flat washers. Make
the screws finger tight.

10.

Dress the ribbon cable under the dc motor, down through the slot in the rear of the cabinet, under the
Power Board and reconnect the ribbon cable connector to J6 on the Power Board.

11.

Secure thetwo ribbon cable clamps to the cabinet base with the 4 (4-40) screws and lockwashers.
CAUTION
Move the carriage to the extreme left to ensure that there is
adequate slack in the print head cable to prevent any strain
being placed on the cable or print head board.

12.

Close the rear access door on the cabinet.

13.

Set the carriage adjustment lever to the minimum gap position (detent closest to the print bar) (Figure
6-5).
CAUTION
It is possible to rotate the carriage adjustment lever beyond
the minimum gap position. If this is done, the correct head gap
adjustment cannot be made.

14.

Adjust the print head gap with the carriage in the center of travel. Place a 12-inch long, 0.012-inch flat
feeler gauge between the print head jewel and the front surface of the print bar. Push the print head snug
against the feeler (Figure 6-6).
CAUTION
Ensure that the feeler gauge rides between the protrusions on
the print head. Do not exert excessive force on the print head
when making the adjustment; it will cause the carriage shaft to
bow, resulting in more than O.012-inch of clearance.

15.

Tighten the 4 (6-32) screws to 10 ±2 in/lbs of torque.
CAUTION
Do not apply more than the recommended torque when
tightening the print head screws or the moulded inserts in the
carriage assembly may be damaged.

16.

Move the print head to the extreme right or left and check for 0.012 ±0.002-inch clearance.

17.

Replace the ribbon and ribbon spools (Figure 6-7).

18 .. With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.
19.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

6-2

20.

Replace the printer cover, printer paper and restore power to the LA36.

CAUTION
Before beginning operation, ensure that the carriage
adjustment lever .is in. the correct position (dependent on the
thickness of the paper).
6.1.2 Timing Belt
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and the ribbon.

Remove the 4 (6-32) screws and lockwashers that secure the print head to the carriage and set the print
head aside (Figure 6-4).

Push on the spring-loaded ribbon drive to relieve the tension on the timing belt and disengage the belt
from the dc motor pulley, carriage, and ribbon drive pulley. Discard the timing belt (Figure 6-8).

Engage the new timing belt on the ribbon drive pulley; push on the spring-loaded ribbon drive and
engage the timing belt on the dc motor pulley and the carriage.

Secure the print head to the carriage with the 4 (6-32) screws, lockwashers and flat washers. Make the
screws finger tight.

Set the carriage adjustment lever to the minimum gap position (detent closest to the print bar) (Figure
6-5).

CAUTION
It is possible to rotate the carriage adjustment lever beyond
the minimum gap position. If this is done, the correct head gap

adjustment cannot be made.
9.

Adjust the print head gap with the carriage in the center of travel. Place a 12-inch long, 0.OI2-inch flat
feeler gauge between the print head jewel and the front surface of the print bar. Push the print head snug
against the feeler (Figure 6-6).

CAUTION
Ensure that the feeler gauge rides between the protrusions on
the print head. Do not exert excessive force on the print head
when making the adjustment; it will cause the carriage shaft to
bow, resulting in more than O.012-inch of clearance.
10.

Tighten the 4 (6-32) screws to 10 ±2 in/lbs of torque.

CAUTION
Do not apply more than the recommended torque when
tightening the print head screws or the moulded inserts in the
carriage assembly may be damaged.

6-3

11.

Move the print head to the extreme right or left and check for 0.012 ±0.002-inch clearance.

12.

Replace the ribbon and ribbon spools (Figure 6-7).

13.

With the ribbon wound on the left spool and moving left to right at the moment of ribbon reversal, a
pull test on the carriage from left to right should indicate a pull of no more than 3.5 Ibs (Figure 6-7).

14.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

15.

Replace the printer cover, printer paper and restore power to the LA36.
CAUTION

Before beginning operation, ensure that the carriage
adjustment lever is in the correct position (dependent on the
thickness of the paper).
6.1.3 LK02 Keyboard Assembly
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the 4 (8-32) screws, lockwashers, flat washers and spacers that secure the keyboard bezel to
the cabinet base (Figure 6-9).

Turn the keyboard bezel upside down on a piece of foam or bubble plastic and remove the 4 (8-32) kep
nuts that secure the keyboard to the bezel. Leave the four hex standoffs in place (Figure 6-10).

Lift the keyboard off the weld studs, disconnect the Berg connector from J2 on the keyboard and set
the keyboard aside (Figure 6-10). If the equipment also uses an LK03 keyboard, disconnect the
connector from Jl on the keyboard.

Reconnect the Berg connector to J2 on the new keyboard. Place the keyboard on the weld studs and
secure with the 4 (8-32) kep nuts.

Replace the keyboard bezel on the cabinet base and secure with the 4 (8-32) screws, lockwashers, flat
washers and spacers.
CAUTION

Ensure that the spacers are placed under the keyboard bezel.
Failure to do so may result in damage to the print head
because of interference with the keyboard connector.
8.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

Replace the printer cover, printer paper and restore power to the LA36.

6.1.4 LK03 Keyboard Assembly
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the 4 (8-32) screws, lockwashers, flat washers and spacers that secure the keyboard bezel to
the cabinet base (Figure 6-10).

Turn the keyboard bezel upside down on a piece of foam or bubble plastic and remove the 4 (8-32) kep
nuts that secure the keyboard to the bezel. Leave the four hex standoffs in place (Figure 6-11).

Lift the keyboard off the weld studs, disconnect the connector from 11 on the keyboard and set the
keyboard aside (Figure 6-11).

Reconnect the connector to 11 on the new keyboard, place the keyboard on the weld studs and secure
with the 4 (8-32) kep nuts.

Replace the keyboard bezel on the cabinet base and secure with the 4 (8-32) screws, lockwashers, flat
washers and spacers.
CAUTION
Ensure that the spacers are placed under the keyboard bezel.
Failure to do so may result in damage to the print head
because of interference with the keyboard connector.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

Replace the printer cover, printer paper and restore power to the LA36.

6.1.5 Printer Mechanism Assembly
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Remove the 4 (6-32) screws, 10ckwashers and flat washers that secure the print head to the carriage and
set the print head aside (Figure 6-4).

Open the rear access door on the cabinet.

Remove the stepping motor and speaker wires from the cable clamp and clip necessary cable ties.
Disconnect the connector from J5 on the Power Board (Figure 6-12).

Remove the dc motor and encoder cables from the cable clamp. Disconnect the connector from J4 on
the Power Board (Figure 6-12).

Pull the cables and wires up through the slots at the rear of the cabinet.

Remove the 6-32 screw that secures the ground wire to the right-hand side plate. Release the ground
wire and replace the screw in the right-hand side plate.

6-5

10.

Remove the 4 (10-32) screws, lockwashers and Buna washers that secure the printer mechanism to the
cabinet base (Figure 6-13).

II.

Remove the printer mechanism from the cabinet base and set aside.

12.

Place the new printer mechanism on the cabinet base and secure with the 4 (10-32) screws, lockwashers
and Buna washers. Make the screws finger tight.

13.

Thread the cables and wires down through the slots at the rear of the cabinet.

14.

Secure the stepping motor and speaker wires in the cable clamp. Reconnect the connector to 15 on the
Power Board.

15.

Secure the dc motor and encoder cables in the cable clamp. Reconnect the connector to 14 on the Power
Board.

16.

Dress the cables and wires inside the cabinet and install cable ties as deemed necessary.

17.

Close the rear access door on the cabinet.

18.

Adjust the position of the printer mechanism (front to back) so that the front surface of the print bar
coincides with the centerline of the reference holes in the cabinet (Figure 6-14). Tighten the 4 (10-32)
screws to 4 ±1 in/lbs of torque.

19.

Check that the carriage has 0.020 to 0.040-inch clearance from the bent-up flange on the cabinet base
when the carriage adjustment lever is in the minimum gap position (detent closest to the print bar)
(Figure 6-5). If necessary, loosen the 4 (10-32) screws that secure the printer mechanism to the cabinet
base and readjust the printer mechanism to attain a minimum of 0.020 inch clearance (Figure 6-15).

20.

Replace the paper in the machine but do not feed it up into the tractors. Pull the paper up through the
cabinet and the printer mechanism to ensure that there is no drag on the paper. Remove the paper from
the machine.

21.

Secure the print head to the carriage with the 4 (6-32) screws, lockwashers and flat washers. Make the
screws finger tight.

22.

Set the carriage adjustment lever to the minimum gap position (detent closest to the print bar) (Figure
6-5).

CAUTION
It is possible to rotate the carriage adjustment lever beyond
the minimum gap position. If this is done, the correct head gap

adjustment cannot be made.
23.

6-6

24.

25.

Move the print head to the extreme right or left and check for 0.012 ±0.002-inch clearance.

26.

Replace the ribbon and ribbon spools (Figure 6-7).

27.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

28.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

29.

Replace the printer cover, printer paper and restore power to the LA36.
CAUTION
Before beginning operation, ensure that the carriage
adjustment lever is in the correct position (dependent on the
thickness of the paper).

6.1.6 DC Motor and Encoder Assembly
I.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Open the rear access door on the cabinet.

Remove the dc motor and encoder cables from the cable clamp. Disconnect the connector from J4 on
the Power Board (Figure 6-12).

Pull the cables up through the slot at the rear of the cabinet.

Push the spring-loaded ribbon drive to relieve the tension on the timing belt and disengage the belt from
the dc motor pulley (Figure 6-8).

Remove the 3 (8-32) screws and hex standoffs that secure the dc motor to the right-hand side plate and
set the motor aside (Figure 6-16).

Secure the new dc motor to the right-hand side plate with the 3 (8-32) screws and hex standoffs.

Thread the dc motor and encoder cables down through the slot at the rear of the cabinet.

10.

Secure the cables in the cable clamp. Reconnect the connector to J4 on the Power Board.

11.

Perform the Encoder Adjustment at the end of this section.

6-7

12.

Close the rear access door on the cabinet.

13.

Push on the ribbon drive and engage the timing belt on the dc motor pulley.

14.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the

I print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 Ibs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.
15.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

16.

Replace the printer cover, printer paper and restore power to the LA36.

Encoder Adjustment
The Motor and Encoder Assembly requires both electrical and mechanical adjustment. The electrical adjustment
should be made first. If the tolerances can be met, mechanical adjustment is not necessary. The electrical adjustment
must be repeated whenever a mechanical adjustment is made.
1.

Release the tension on the timing belt by pressing the spring-loaded ribbon drive assembly; slip the
timing belt from the pulley on the motor shaft.

Lower the rear access door.

Set scope as follows:
VERTICAL DISPLAY CHI and CH2:

2 V/DIV (XIO PROBES)

COUPLING CHI and CH2:

VERTICAL MODE:

SELECT CHI

TIME BASE:

100 IJ.s/DIV

TRIGGER:

NORMAL

SOURCE:

SELECT CHI

SLOPE:

POSITIVE

LEVEL:

POSITIVE

Connect scope CHI probe to PIN 8 of E-6 and CH2 probe to PIN 6 of E-6 or to TPI and TP2 of Logic
. BoardM7722.

Turn power on, motor will rotate clockwise as viewed from the Encoder end .
. NOTE
If the Encoder is drastically out of adjustment, the motor may
tum in either direction and the speed may vary from very fast
to zero. Encoder readjustment will correct these conditions.
If the Motor is turning counterclockwise, the waveform for
quadrature will be reversed. That is, eH 1 wnI lead by 90° .

6-8

Select Channel 1, set vertical to CHI and trigger source to CHI, then check waveform for 50% Duty
Cycle (Figure 6-17).
NOTE
Use uncalibrated sweep and adjust variable sweep for 1 cycle
to equal 10 divisions, thus SO% Duty Cycle is equal to S
divisions.
If adjustment is necessary, refer to Step 8.

Select Channel 2, set vertical to CH2 and trigger source to CH2, then check for 50% Duty Cycle as in
Step 6.
If adjustment is necessary, refer to Step 8.

To make adjustments on Encoder, carefully remove the protective housing on the rear of the motor.
a.

To adjust CHI Duty Cycle, adjust R-2 (Figure 6-18) on Encoder until correct.

To adjust CH2 Duty Cycle, adjust R-l (Figure 6-18) on Encoder until correct.

Gylptol both pots and re-check adjustment. Jitter should not exceed 1.4 divisions (Figure 6-19)
measured from leading edge to trailing edge.

Select Channel 1 as trigger source and set vertical mode to alternate.
Channel 2 should lead Channel 1 by 90° ± 20° (Figure 6-20). If not, loosen the two Encoder screws
reposition the Encoder Subassembly as required and tighten screws.
CAUTION
Exercise extreme caution when adjusting Encoder to avoid
bending or damaging the disk or coming in contact with the
rotating disk.

10.

Turn power off.

11.

Replace Encoder cover carefully.

12.

Reinstall timing belt by pressing the spring-loaded ribbon drive assembly to release tension; slip the
timing belt onto the pulley on the motor shaft.

13.

Replace the printer housing.

14.

Close rear access door.

6.1.7 Ribbon Drive Assembly

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
.
the housing aside (Figure 6-1).

6-9

Remove the ribbon spools and ribboJl.

Push on the ribbon drive to relieve the tension on the timing belt and disengage the belt from the dc
motor pulley and the ribbon drive pulley (Figure 6-8).

Remove the retaining ring that holds the pushrod in the ribbon chassis'(Figure 6-21).

Rotate the ribbon drive pulley until the clutch eccentric is at its highest point (Figure 6-21).

Remove the 8-32 screw, lockwasher and flat washer that secure the ribbon drive to the upper pivot tab
on the left-hand side plate (Figure 6-21).

Remove the ribbon drive by pulling out at the top. This will free the assembly from the upper pivot tab.
Lift up on the ribbon drive to clear the lower pivot. Rotate the drive counterclockwise and pull toward
the rear. This will free the retaining stop foot and allow the compression ring to drop free (Figure 6-21).

Carefully remove the ribbon drive and the pushrod.··

10.

Rotate the ribbon drive pulley on the new ribbon drive until the clutch eccentric is at its highest point.

11.

Push the pushrod through the left-hand side plate and engage the retaining stop foot in the left-hand side
plate.

12.

Insert the compression spring between the left-hand side plate and the ribbon drive.

13.

Push the rear ofthe drive assembly toward the side plate and engage the lower pivot point.

14.

Slide the upper pivot point under the pivot tab on the side plate and secure with the 8-32 screw,
lockwasher and flat washer. Make the screw finger tight.

NOTE
Before. pushiltg the upper pivot point under the pivot tab,
ensure that the flat side of the pivot is resting against the
.
raised portion of the pivot tab.
15.

Replace the retaining ring that holds the pushrod in the ribbon chassis.

16.

Replace the timing belt on the ribbon drive pulley and the dc motor pulley.

17.

Replace the ribbon and ribbon spools (Figure 6-7).

18.

Rotate the ribbon drive pulley and check the travel of the pushrod to either side of center of the
elongated slot in the ribbon chassis. The travel should be equal on either side of center (Figure 6-22).

19.

To attain equal travel, move the ribbon drive upper pivot point in the direction of the shortest distance
of travel. When travel is equal on both sides of the elongated hole, tighten the 8-32 upper pivot screw to
18 ±2 in/lbs of torque.
.

NOTE
The eccentric tab should be bent at a 90° angle (Figure 6-21)
when viewed from the left side of the unit. If the angle is not
at 90°, bend to the correct angle.

6-10

20.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 Ibs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

21.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

22.

Replace the printer cover, printer paper and restore power to the LA36.

6.1.8 Carriage Assembly
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Remove the 4 (6-32) screws and lockwashers that secure the print head to the carriage. Carefully lay
the print head aside (Figure 6-4).

Push on the spring-loaded ribbon drive to relieve the tension on the timing belt and disengage the belt
from the dc motor pulley, carriage and ribbon drive pulley. Lay the timing belt aside (Figure 6-8).

Open the rear access door on the cabinet.

Remove the stepping motor and speaker wires from the cable clamp and clip necessary cable ties.
Disconnect the connector from J5 on the Power Board (Figure 6-12).

Remove the dc motor and encoder cables from the cable clamp. Disconnect the connector from J4 on
the Power Board (Figure 6-12).

Pull the cables and wires up through the slots at the rear of the cabinet.

10.

Remove the 6-32 screw that secures the ground wire to the right-hand side plate. Release the ground
wire and replace the screw in the right-hand side plate.

11.

Remove the 4 (10-32) screws, lockwashers and Buna washers that secure the printer mechanism to the
cabinet base (Figure 6-13).

12.

Set the printer mechanism on the workbench.

13.

Remove the 3 (8-32) screws and hex standoffs that secure the dc motor to the right-hand side plate
(Figure 6-16). Set the dc motor aside.

14.

Remove the two speaker leads.

15.

Remove the 2 (6-32) screws and lockwashers that secure the right-hand side plate to the ribbon chassis
(Figure 6-23).

16.

Remove the two retaining rings that secure the tractor support shaft in the right-hand side plate (Figure
6-23).

6-11

17.

On equipment with serial number 6219 and below, remove the retaining ring and flat washers that secure
the tractor drive shaft in the right-hand side plate. (Note the quantity of flat washers removed.) On
equipment with serial number 6220 and higher, remove the retaining ring that secures the tractor drive
shaft in the left-hand side plate. (The retaining ring and flat washers have been eliminated on the
right-hand side.)

18.

Remove the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate (Figure 6-23).

19.

Remove the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate (Figure 6-23).

20.

Carefully remove the right-hand side plate (Figure 6-23).

21.

Carefully slide the carriage off the two carriage shafts. (place your hand beneath the carriage to catch the
plain bushing as it slides off the rear carriage shaft.)

22.

Replace the plain bushing in the new carriage and slide the bushing and the new carriage onto the
carriage shafts.

23.

Replace the right-hand side plate.

24.

Replace the two retaining rings that secure the tractor support shaft in the right-hand side plate.

25.

On equipment with serial number 6219 and below replace the flat washers and retaining ring that secure
the tractor drive shaft in the right-hand side plate. On serial number 6220 and higher, replace the
retaining ring that secures the tractor drive shaft in the left-hand side plate.

26.

Replace the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate. Make the screw finger tight.

27.

Replace the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate. Tighten the rear screw only to 18 ±2 in/lbs of torque.

28.

Replace the 2 (6-32) screws and lockwashers that secure the right-hand side plate to the ribbon chassis.
Tighten the screws (be sure to place the ground strap on the top screw and tighten the screw to 20
±2 in/lbs of torque).

29.

Loosen the 2 (8-32) screws that secure the ribbon chassis to the print bar (Figure 6-23).

30.

Loosen the 1/4-20 screw that secures the print bar to the left-hand side plate, then make screw fmger
tight. Push the print bar to the rear as far as possible.

31.

Loosen the 10-32 screw that secures the front carriage shaft to the left-hand side plate.

32.

Set up and calibrate the Print Bar Alignment Tool (94-11424-2). (Refer to Section 5.3.17.)

33.

Place the alignment tool on the two carriage shafts with the vee slot resting on the front shaft (Figure
6-24).

34.

Slide the tool to the right until it rests against the right-hand side plate. With a plastic hammer, tap the
print bar toward the front of the machine until the indicator reads zero (Figure 6-24).

6-12

35.

Remove the alignment tool and place it on the extreme left-hand side of the carriage shaft against the
right-hand side plate. Again tap the print bar until the indicator reads zero.

36.

Tighten the 2 (1/4-20) screws that secure the print bar to the right- and left-hand side plates to 30
±2 in/lbs of torque.

NOTE
This adjustment ensures that the face of the print bar is 2.562
inch from the center line of the front carriage shaft.
37.

With the carriage at the extreme left-hand side plate, place the alignment tool on the carriage shafts in
the center of carriage travel with the indicator button resting against the face of the print bar (Figure
6-24).

38.

Slowly rotate the front carriage shaft until the indicator reads +0.001 to 0.0015 (Figure 6-24).

NOTE
This adjustment preloads the front carriage shaft to
compensate for distortion caused by the heavy spring tension
of the Ribbon Drive Assembly.
39.

Tighten the 2 (10-32) screws that secure the front carriage shaft to the right- and left-hand side plates
to 18 ±2 in/lbs of torque.

40.

Tighten the 2 (8-32) screws that secure the ribbon chassis to the print bar.

41.

Secure the Encoder motor to the right-hand side plate with the 3 (8-32) screws and the hex standoffs.

42.

Place the printer mechanism on the cabinet base and secure with the 4 (10-32) screws, lockwashers and
Buna washers. Make the screws finger tight.

43.

Thread the cables and wires down through the slots at the rear of the cabinet.

44.

Secure the stepping motor and speaker wires in the cable clamp. Reconnect the connector to J5 on the
Power Board.

45.

Secure the dc motor and encoder cables in the cable clamp. Reconnect the connector to J4 on the Power
Board.

46.

Dress the cables and wires inside the cabinet and install cable ties as deemed necessary.

47.

Close the rear access door on the cabinet.

48.

Align the position of the printer mechanism (front to back) so that the front surface of the print bar
coincides with the centerline of the reference holes in the cabinet (Figure 6-14). Tighten the 4 (10-32)
screws to 4 ±1 in/lbs of torque.

49.

Check that the carriage has 0.020 to O.040-inch clearance from the bent-up flange on the cabinet base
when the carriage adjustment lever is in the minimum gap position (detent closest to the print bar)
(Figure 6-5). If necessary, loosen the 4 (10-32) screws that secure the printer mechanism to the cabinet
base and realign the printer mechanism to attain a minimum of 0.020 inch clearance (Figure 6-15).

6-13

50.

51.

Secure the print head to the carriage with the 4 (6-32) screws and lockwashers. Make the screws fmger
tight.

52.

Set the carriage adjustment lever to the minimum gap position (detent closest to the print bar) (Figure
6-5).

CAUTION
It is possible to rotate the carriage adjustment lever beyond
the minimum gap position. If this is done, the correct head gap
adjustment cannot be made.
53.

Tighten the 4 (6-32) screws to 10 ±2 in/lbs of torque.

CAUTION
Do not apply more than the recommended torque when
tightening the print head screws or the moulded inserts in the
carriage assembly may be damaged.
55.

Move the print head to the extreme right or left and check for 0.012 ±0.002-inch clearance.

56.

Replace the ribbon and ribbon spools (Figure 6-7).

57.

With the ribbon fully wound on the left spool, the ribbon moving rightto left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

58.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

59.

Replace the printer cover, printer paper and restore power to the LA36.

CAUTION
Before beginning operation, ensure that the carriage
adjustment lever is in the correct position (dependent on the
thickness of the paper).

6-14

6.1.9 Ribbon Chassis Assembly
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Clip the three cable ties that secure the speaker wires to the ribbon chassis (Figure 6-25).

Remove the retaining ring that holds the pUshrod in the ribbon chassis (Figure 6-25).

Remove the 4 (6-32) screws and lockwashers that secure the ribbon chassis to the right- and left-hand
side plates (Figure 6-25).

Remove the 2 (8-32) screws and lockwashers that secure the ribbon chassis to the print bar (Figure
6-25).

Remove the ribbon chassis and set aside.

Secure the new ribbon chassis to the print bar with the 2 (8-32) screws and lockwashers.

10.

Replace the 4 (6-32) screws and lockwashers that secure the ribbon chassis to the right- and left-hand
side plates. (Be sure to attach the ground strap to the top screw on the right-hand side and tighten the
ground screw 20 ±2 in/lbs of torque.)

11.

Replace the retaining ring that holds the pUshrod in the ribbon chassis.

12.

Secure the speaker wires to the ribbon chassis with cable ties.

13.

Remove the 4 (6-32) screws, lockwashers and flat washers that secure the print head to the carriage and
set the print head aside.

14.

Remove the 4 (10-32) screws, lockwashers and Buna washers that secure the printer mechanism to the
cabinet base (Figure 6-13).

15.

Lift the printer mechanism at the front, tilt toward the rear and let the mechanism rest on the side plates
(Figure 6-26).

16.

Slide the reverse sensor to the right and rotate the ribbon drive pulley several times. Measure the
clearance between the main pawl tab and the right-hand interposer (Figure 6-26).

17.

Slide the reverse sensor to the left and rotate the ribbon drive pulley until the main pawl shifts to the
opposite side. Rotate the pulley several more times.

18.

Measure the clearance between the main pawl tab and the left-hand interposer.

19.

The two clearances must be equal within 0.020 inch.

20.

If the two clearances are not equal within 0.020 inch, move the upper pivot point toward the side having

the greatest clearance. Tighten the upper pivot screw.

6-15

21.

Perform Steps 16-18. If the clearances are not within 0.020 inch, loosen the upper pivot screw and
readjust the upper pivot.

22.

When the clearances are equal within the 0.020 inch, tighten the upper pivot screw to 18 ±2 in/lbs of
torque.

23.

Rotate the printer mechanism back into place on the cabinet base and secure with the 4 (10-32) screws,
lockwashers and Buna washers. Make screws finger tight.

24.

25.

26.

27.

Secure the print head to the carriage with the 4 (6-32) screws, lockwashers and flat washers. Make the
screws finger tight.

28.

29.

Adjust the print head gap with the carriage in the center of travel. Place a l2-inch long, 0.012-inch flat
feeler gauge between the print head jewel and the front surface of the print bar. Push the print head snug
against the feeler (Figure 6-6).
CAUTION

Ensure that the feeler gauge rides between the protrusions on
the print head. Do not exert excessive force on the print head
when making the adjustment; it will cause the carriage shaft to
bow, resulting in more than O.012-inch of clearance.
30.

Tighten the 4 (6-32) screws to 10 ±2 in/lbs of torque.
CAUTION

Do not apply more than the recommended torque when
tightening the print head screws or the moulded inserts in the
carriage assembly may be damaged.
31.

Move the print head to the extreme right or left and check for 0.012 ±0.002-inch clearance.

6-16

32.

Replace the ribbon and ribbon spools (Figure 6-7).

33.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

34.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

35.

6.1.10 Idler Gear Assembly
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the 2 (8-32) screws, lockwashers and flat washers that secure the idler gear assembly to the
left-hand side plate (Figure 6-27).

Secure the new idler gear assembly to the left-hand side plate with the 2 (8-32) screws, lockwashers and
flat washers. Make the screws finger tight.

With the idler gear in mesh with the stepping motor gear and the tractor drive gear, adjust the idler gear
to achieve equal depth penetration and a backlash of 0.002 to 0.007 inch between each pair of gears
(Figure 6-27). (The idler gear should be free to slide in and out.)

Tighten the 2 (8-32) screws to 18 ±2 in/lbs of torque.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

Replace the printer cover, printer paper and restore power to the LA36.

6.1.11 Tractor Assembly (RH or LH)
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Loosen the screw shaft on the right.hand tractor and the 10-32 screw on the left-hand tractor (Figure
6-28).

6-17

Grasp the line feed kno.b and pull the square tracto.r drive shaft o.ut o.f the right- and left-hand tracto.rs
(Figure 6-28).
Remo.ve .the two. retaining rings that secure the tracto.r suppo.rt shaft in the right-hand side plate (Figure

~~.

Remo.ve the tracto.r suppo.rt shaft and the right- and left-hand tracto.rs fro.m the side plates.

Replace whichever tracto.r is defective.

Replace the tracto.r suppo.rt shaft in the side plates.

Replace the two. retaining rings that secure the tracto.r suppo.rt shaft in the right-hand side plate.

NOTE
Ensure that the index marks on the outside of the upper
tractor bushings coincide with the same flat on the square
shaft (Figure 6-29). If the bushings are not scribed, rotate the
tractors untiJ a tractor pin on both tractors is centered on the
same flat.
10.

Push the square tracto.r drive shaft through the left-hand side plate and through the left- and right-hand
tracto.rs.

11.

On equipment with serial number 6219 and belo.w, replace the flat washers and retaining ring that secure
the tracto.r drive shaft in the right-hand side plate. On serial number 6220 and higher, replace the
retaining ring that secures the tracto.r drive shaft in the left-hand side plate.

12.

Slide the left-hand tractor to. the left so. that the feed pins are 1-7/8 inches fro.m the left-hand side plate.
Tighten the 10-32 screw o.n the left-hand tracto.r (Figure 6-29).

13.

Slide the right-hand tracto.r from side to. side. If it appears to. bind or have excessive drag on the shafts,
grasp the tracto.r suppo.rt shaft and mo.ve it up o.r do.wn in its slo.ts until the tracto.r slides easily o.n the
shafts.

14.

The right-hand tracto.r will be adjusted to. the width o.f paper or fo.rms to. be llsed.

15.

Replace the printer co.ver, printer paper and resto.re po.wer to. the LA36.

6.1.12 Stepping Motor Assembly

Remo.ve po.wer fro.m the LA36. Remo.ve the printer paper and the printer co.ver.

Remo.ve the 8 (6-18) screws and flatwashers that secure the printer ho.using to. the cabinet base and set
the ho.using aside (Figure 6-1).

Remo.ve the ribbo.n spo.o.ls and ribbo.n.

Remo.ve the 2 (8-32) screws, lo.ckwashers and flat washers that secure the idler gear to. the left-hand side
plate (Figure 6-27).

Open the rear access do.o.r o.n the cabinet.

6-18

Remove the stepping motor and speaker wires from the cable clamp and clip necessary cable ties.
Disconnect the connector from J5 on the Power Board (Figure 6-12).

Pull the wires up through the slot at the rear of the cabinet.

Use a Pin Removal Tool (AMP PIN 1-305183-1) and remove the four motor leads from pin Nos. 4, 5, 6
and 7 on the connector (Figure 6-30).

Remove the 4 (8-32) screws, flat washers, lockwashers and hex nuts that secure the stepping motor to
the left-hand side plate. Set the stepping motor aside (Figure 6-31).

10.

Use a Pin Insertion Tool (AMP PIN 91002-1) to insert the leads on the new stepping motor in connector
pin Nos. 4, 5, 6 and 7 (Figure 6-30).

11.

Secure the new stepping motor to the left-hand side plate with the 4 (8-32) screws, flat washers,
lockwashers and hex nuts. The hex nuts and lockwashers go on the inside of the left-hand side plate.
(Allow the stepping motor to drop to its lowest point in the elongated slots.)

12.

Tighten the 4 (8-32) screws to 18 ±2 inllbs of torque.

13.

Secure the idler gear to the left-hand side plate with the 2 (8-32) screws, lockwashers and flat washers.
Make the screws finger tight.

14.

15.

Tighten the 2 (8-32) screws to 18 ±2 inllbs of torque.

16.

Secure the stepping motor wires and the speaker wires with cable ties and thread them under the printer
mechanism and pushrod and down through the slot at the rear of the cabinet. Reconnect the connector
to J 5 on the Power Board.

17.

Secure the bundled wires in the cable clamp.

18.

Replace the ribbon and ribbon spools.

19.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 Ibs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

20.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

21.

Replace the printer cover, printer paper and restore power to the LA36.

6.1.13 Logic Board Assembly (M7722)
1.

Remove power from the LA36. Remove the printer paper.

Open the rear access door on the cabinet.

6-19

Disconnect the connectors from Jl, J2, J3 and the quick-disconnects from the +5 V (red) and ground
(black) on the Logic Board (Figure 6-32). If the EIA option is installed, disconnect the connector from
J4. (There will not be a connector in J2.)

Remove the 6 (8-32) screws, lockwashers and flat washers that secure the Logic Board to the rear access
door and set the Logic Board aside (Figure 6-32).

Place the new Logic Board on the standoffs and secure to the rear access door with the 6 (8-32) screws,
lockwashers and flat washers. (Looking from the rear, loop the cable clamp over the right-front standoff
before securing the Logic Board.) Tighten the screws to 16 ±2 in/lbs of torque.

Reconnect the connectors to J1, J2 and 13 and the quick-disconnects to the +5 V (red) and ground
(black) on the Logic Board.

Close the rear access door on the cabinet.

Replace the printer paper and restore power to the LA36.

6.1.14 Power Board Assembly

Remove power from the LA36 and remove the printer paper.

Open the rear access door on the cabinet.

Disconnect the connectors from J2, J3, J4, J5, J6 and the qUick-disconnects from the +5 V (red) and
ground (black) on the Power Board. Disconnect the connector from J1 on the Logic Board (Figure
6-33).

Remove the 6 (8-32) screws, lockwashers and flat washers that secure the Power Board to the cabinet.
Set the Power Board aside (Figure 6-33).

Place the new Power Board in the cabinet and secure with the 6 (8-32) screws, lockwashers and flat
washers. Tighten the screws to 16 ±2 in/lbs of torque.

Reconnect the connectors to J2, 13, J4, J5, J6 and the quick-disconnects to the +5 V (red) and ground
(black) on the Power Board. Reconnect the connector to J1 on the Logic Board.

Close the rear access door on the cabinet.

Replace the printer paper and restore power to the LA36.

6.1.15 Fan Assembly

Remove power from the LA36. Remove the printer paper.

Open the rear access door on the cabinet.

Remove the 4 (6-32) screws and lockwashers that secure the fan to the cabinet (Figure 6-34).

Disconnect the qUick-disconnect from the fan and set the fan aside (Figure 6-34).

Reconnect the qUick-disconnect to the new fan.

6-20

Secure the fan to the cabinet with the 4 (6-32) screws and lockwashers.

Close the rear access door on the cabinet.

Replace the printer paper and restore power to the LA36.

6.1.16 Transformer Assembly
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Open the rear access door on the cabinet.

Disconnect the connector from 13 on the Power Board (Figure 6-35).

Remove the 2 (8-32) screws and lockwashers that secure the fuse mounting bracket to the cabinet
(Figure 6-35).

Remove the green jumper wire from capacitor C5 (Figure 6-36).

Disconnect the quick-disconnect from the fan assembly (Figure 6-35).

Remove the 4 (8-32) screws, lockwasher and flat washers that secure the keyboard bezel to the cabinet
base (Figure 6-9).

Turn the keyboard upside down and remove the quick-disconnects from the left-most rocker switch
(Figure 6-37).

10.

Clip all the cable ties from the keyboard to the transformer.

11.

Pull the two wires that were removed from the rocker switch down through the slot in the rear of the
cabinet.

12.

Remove the 4 (8-32) screws, lockwashers and kep nuts that secure the transformer to the cabinet base.
Disconnect the 115 V-230 V jumper from connector 11 and set the transformer aside (Figure 6-35).

13.

Place the new transformer in the cabinet and secure with the 4 (8-32) screws, lockwashers and kep nuts.
(Be sure to reconnect the ground strap to the rear screw on the transformer.) Tighten the ground strap
screw to 20 ±2 in/lbs of torque.

14.

Pull the two wires up through the slot in the rear of the cabinet and reconnect the quick-disconnects to
the rocker switch on the keyboard.

15.

Replace the keyboard bezel on the cabinet base and secure with the 4 (8-32) screws, lockwashers and
flat washers.

16.

Reconnect the quick-disconnect to the fan assembly.

17.

Dress the wires and cables from the keyboard to the transformer and secure with cable ties.

6-21

18.

Reconnect the connector to J3 on the Power Board.

19.

Replace the green jumper wire on capacitor CS.

20.

Secure the fuse mounting bracket to the cabinet with the 2 (8-32) screws and lockwashers.

21.

Close the rear access door on the cabinet.

22.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

23.

Replace the printer cover, printer paper and restore power to the LA36.

6.1.17 Line Filter Assembly
1.

Remove power from the LA36 and remove the printer paper.

Open the rear access door on the cabinet.

Remove the 2 (8-32) screws and lockwashers that secure the fuse mounting bracket to the cabinet
(Figure 6-35).

Disconnect all external wires that connect to capacitor CS and fuse F1 (Figure 6-36).

Remove the fuse mounting bracket and set aside.

Reconnect all external wires to capacitor CS and fuse F1 in the new line filter.

Secure the fuse mounting bracket to the cabinet with the 2 (8-32) screws and lockwashers.

Close the rear access door on the cabinet.

Replace the printer paper and restore power to the LA36.

6.2 DISASSEMBLY , ASSEMBLY AND ADJUSTMENT PROCEDURES
6.2.1 Print Bar
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Remove the 4 (6-32) screws and lockwashers that secure the print head to the carriage. Carefully lay
the print head aside (Figure 6-4).

Open the rear access door on the cabinet.

6-22

Remove the stepping motor and speaker wires from the cable clamp and clip necessary cable ties.
Disconnect the connector from J5 on the Power Board (Figure 6-12).

Remove the dc motor and encoder cables from the cable clamp. Disconnect the connector from J4 on
the Power Board (Figure 6-12).

Pull the cables and wires up through the slots at the rear of the cabinet.

10.

Remove the 6-32 screw that secures the ground wire to the right-hand side plate. Release the ground
wire and replace the screw in the right-hand side plate.

11.

Remove the 4 (10-32) screws, lockwashers and Buna washers that secure the printer mechanism to the
cabinet base (Figure 6-13).

12.

Set the printer mechanism on the workbench.

13.

Remove the 3 (8-32) screws and hex standoffs that secure the dc motor to the right-hand side plate
(Figure 6-16). Set the dc motor aside.

14.

Remove the two speaker leads.

15.

Remove the 2 (6-32) screws and lockwashers that secure the right-hand side plate to the ribbon chassis
(Figure 6-23).

16.

Remove the two retaining rings that secure the tractor support shaft in the right-hand side plate (Figure
6-23).

17.

18.

Remove the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate (Figure 6-23).

19.

Remove the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate (Figure 6-23).

20.

Carefully remove the right-hand side plate (Figure 6-23).

21.

Remove the 2 (8-32) screws that secure the ribbon chassis to the print bar (Figure 6-38).

22.

Remove the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the left-hand side
plate. Set the print bar aside (Figure 6-38).

23.

Secure the new print bar to the left-hand side plate with the 1/4-20 screw, lockwasher and flat washer.
(Ensure that the narrow chamber is faCing up.)

24.

Replace the right-hand side plate.

25.

Replace the two retaining rings that secure the tractor support shaft in the right-hand side plate.

6-23

26.

On equipment with serial number 6219 and below, replace the flat washers and retaining ring that secure
the tractor drive shaft in the right-hand side plate. On serial number 6220 and higher, replace the
retaining ring that secures the tractor drive shaft in the left-hand side plate.

27.

Replace the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate. Make the screw finger tight.

28.

Replace the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate. Tighten the rear screw only to 18 ±2 in/lbs of torque.

29.

Replace the 2 (6-32) screws and lockwashers that secure the right-hand side plate to the ribbon chassis.
Tighten the screws. (Be sure to place the ground strap on the top screw and tighten the screw to 20
±2 in/lbs of torque.)

30.

Replace the 2 (8-32) screws that secure the ribbon chassis to the print bar (Figure 6-23). Make the
screws finger tight.

31.

Loosen the 1/4-20 screw that secures the print bar to the left-hand side plate, then make screw finger
tight. Push the print bar to the rear as far as possible.

32.

Loosen the 10-32 screw that secures the front carriage shaft to the left-hand side plate.

33.

Set up and calibrate the Print Bar Alignment Tool (94-11424-2). (Refer to Section 6.2.17.)

'34.

Place the alignment tool on the two carriage shafts with the vee slot resting on the front shaft (Figure
6-24).

35.

Slide the tool to the left until it rests against the right-hand side plate. With a plastic hammer, tap the
print bar toward the front of the machine until the indicator reads zero (Figure 6-24).

36.

Remove the alignment tool and place it on the extreme left-hand side of the carriage shaft against the
right-hand side plate. Again tap the print bar until the indicator reads zero.

37.

Tighten the 2 (1/4-20) screws that secure the print bar to the right- and left-hand side plates to 30
±2 in/lbs of torque.
NOTE

This adjustment ensures that the face of the print bar is 2.562
inch from the center line of the front carriage shaft.
38.

39.

Slowly rotate the front carriage shaft until the indicator reads +0.001 to 0.0015 (Figure 6-24).
NOTE

This adjustment preloads the front carriage shaft to
compensate for distortion caused by the heavy spring tension
of the Ribbon Drive Assembly.

6-24

40.

Tighten the 2 (10-32) screws that secure the front carriage shaft to the right- and left-hand side plates
to 18 ±2 in/lbs of torque.

41.

Tighten the 2 (8-32) screws that secure the ribbon chassis to the print bar.

42.

Secure the encoder motor to the right-hand side plate with the 3 (8-32) screws and the hex standoffs.

43.

Place the printer mechanism on the cabinet base and secure with the 4 (10-32) screws, lockwashers and
Buna washers. Make the screws finger tight.

44.

Thread the cables and wires down through the slots at the rear of the cabinet.

45.

Secure the stepping motor and speaker wires in the cable clamp. Reconnect the connector to J5 on the
Power Board.

46.

Secure the dc motor and encoder cables in the cable clamp. Reconnect the connector to J4 on the Power
Board.

47.

Dress the cables and wires inside the cabinet and install cable ties as deemed necessary.

48.

Close the rear access door on the cabinet.

49.

50.

51.

52.

Secure the print head to the carriage with the 4 (6-32) screws and lockwashers. Make the screws finger
tight.

53.

adjustment cannot be made.

6-25

54.

Adjust the print head gap with the carriage in the center of travel. Place a 12-inch long, 0.0 12-inch flat
feeler gauge between the print head jewel and the front surface of the print bar. Push the print head snug
against the feeler (Figure 6-6).
CAUTION
Ensure that the feeler gauge rides between the protrusions on
the print head. Do not exert excessive force on the print head
when making the adjustment; it will cause the carriage shaft to
bow, resulting in more than O.OI2-inch of clearance.
Tighten the 4 (6-32) screws to 10 ±2 in/lbs of torque.

55.

CAUTION
Do not apply more than the recommended torque when
tightening the print head screws or the moulded inserts in the
carriage assembly may be damaged.
56.

Move the print head to the extreme right or left and check for 0.012 ±0.002·inch clearance.

57.

Replace the ribbon and ribbon spools (Figure 6-7).

58.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
I print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
I

carriage from the left to right should indicate a pull of no more than 3.5 lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

59.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

60.

6.2.2 Tractor Drive Shaft
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Loosen the screw shaft on the right-hand tractor and the 6-32 screw on the left·hand tractor (Figure
6-39).

Grasp the line feed knob and pull the tractor drive shaft to the left, out of the right-hand side plate
(Figure 6-39).

Remove the 6-32 screw from the end of the tractor drive shaft (Figure 6·40).

6-26

Remove the line feed clutch, coupling and the line feed knob from the tractor drive shaft (Figure 6-40).

Replace the line feed clutch, coupling and line feed knob on the new tractor drive shaft. Secure with the
6-32 screw.

NOTE
Ensure that the index marks on the outside of the upper
tractor bushings coincide with the same flat on the square
shaft (Figure 6-29). If the bushings are not scnDed, rotate the
tractors until a tractor pin on both tractors is centered on the
same flat.
8.

Push the square tractor drive shaft through the left-hand side plate and through the left- and right-hand
tractors.

10.

Slide the left-hand tractor to the left so that the feed pins are 1-7/8 inches from the left-hand side plate.
Tighten the 10-32 screw on the left-hand tractor (Figure 6-29).

11.

Slide the right-hand tractor from side to side. If it appears to bind or have excessive drag on the shafts,
grasp the tractor support shaft and move it up or down in its slots until the tractor slides easily on the
shafts.

12.

The right-hand tractor will be adjusted to the width of paper or forms to be used.

13.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.3 Tractor Support Shaft
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Loosen the screw shaft on the right-hand tractor and the 10-32 screw on the left-hand tractor (Figure
6-41).

Remove the two retaining rings that secure the tractor support shaft in the right-hand side plate (Figure
6-41).

Remove the tractor support shaft from the left- and right-hand tractors through the right-hand side plate
(Figure 6-41).

NOTE
As the tractor shaft clears each tractor, catch the clamp collar
as it falls free of the tractor and the shaft.
5.

Slide the new tractor support shaft through the slot in the right-hand side plate, the screw shaft clamp
collar and the right-hand tractor, then through the left-hand tractor, the clamp collar and the left-hand
plate.

Replace the two retaining rings that secure the tractor support shaft in the right-hand side plate.

6-27

Slide the left-hand tractor to the left so that the feed pins are 1-7/8 inches from the left-hand side plate.
Tighten the 10-32 screw on the left-hand tractor (Figure 6-29).

The right-hand tractor will be adjusted to the width of paper or forms to be used.

lO.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.4 Carriage Shaft(s)
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Remove the 4 (6-32) screws and lockwashers that secure the print head to the carriage. Carefully lay
the print head aside (Figure 6-4).

Open the rear access door on the cabinet.

Remove the stepping motor and speaker wires from the cable clamp and clip necessary cable ties.
Disconnect the connector from J5 on the Power Board (Figure 6-12).

Remove the dc motor and encoder cables from the cable clamp. Disconnect the connector from J4 on
the Power Board (Figure 6-12).

Pull the cables and wires up through the slots at the rear of the cabinet.

10.

Remove the 6-32 screw that secures the ground wire to the right-hand side plate. Release the ground
wire and replace the screw in the right-hand side plate.

11.

Remove the 4 (10-32) screws, lockwashers and Buna washers that secure the printer mechanism to the
cabinet base (Figure 6-13).

12.

Set the printer mechanism on the workbench.

13.

Remove the 3 (8-32) screws and hex standoffs that secure the dc motor to the right-hand side plate
(Figure 6-16). Set the dc motor aside.

14.

Remove the two speaker leads.

15.

Remove the 2 (6-32) screws and lockwashers that secure the right-hand side plate to the ribbon chassis
(Figure 6-23).

6-28

16.

Remove the two retaining rings that secure the tractor support shaft in the right-hand side plate (Figure
6-23).

17.

18.

Remove the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate (Figure 6-23).

19.

Remove the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate (Figure 6-23).

20.

Carefully remove the right-hand side plate (Figure 6-23).

21.

Carefully slide the carriage off the two carriage shafts. (place your hand beneath the carriage to catch the
plain bushing as it slides off the rear carriage shaft.)

22.

Remove the 10-32 screw, lockwashers and flat washer that secure the front or rear carriage shaft to the
left-hand side plate (dependent on which shaft is to be replaced) (Figure 6-42).

23.

Secure the front or rear carriage shaft to the left-hand side plate with the 10-32 screw, lockwasher and
flat washer. If the rear carriage shaft is replaced, tighten the screw to 18 ±2 in/lbs of torque and at the
same time, loosen the 10-32 screw on the front shaft. If the front carriage shaft is replaced, make the
10-32 screw finger tight.

24.

Replace the plain bushing and the carriage on the carriage shafts.

2S.

Replace the right-hand side plate.

26.

Replace the two retaining rings that secure the tractor support shaft in the right-hand side plate.

27.

On equipment with serial number 6219 and below, replace the flat washer and retaining ring that secure
the tractor drive shaft in the right-hand side plate. On serial number 6220 and higher, replace the
retaining ring that secures the tractor drive shaft in the left-hand side plate.

28.

Replace the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate. Make the screw finger tight.

29.

Replace the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate. Tighten the rear screw only to 18 ±2 in/lbs of torque.

30.

31.

Loosen the 2 (8-32) screws that secure the ribbon chassis to the print bar (Figure 6-23).

32.

Loosen the 1/4-20 screw that secures the print bar to the left-hand side plate, then make screw finger
tight. Push the print bar to the rear as far as possible.

6-29

33.

Loosen the 10-32 screw that secures the front carriage shaft to the left-hand side plate.

34.

Set up and calibrate the Print Bar Alignment Tool (94-11424-2). (Refer to Section 6.2.17.)

35.

Place the alignment tool on the two carriage shafts with the vee slot resting on the front shaft (Figure
6-24).

36.

Slide the tool to the left until it rests against the right-hand side plate. With a plastic hammer, tap the
print bar toward the front of the machine until the indicator reads zero (Figure 6-24).

37.

Remove the alignment tool and place it on the extreme left-hand side of the carriage shaft against the
right-hand side plate. Again tap the print bar until the indicator reads zero.

38.

Tighten the 2 (1/4-20) screws that secure the print bar to the right- and left-hand side plates to 30
±2 in/lbs of torque.

NOTE
This adjustment ensures that the face of the print bar is 2.562
inch from the center line of the front carriage shaft.

39.

40.

Slowly rotate the front carriage shaft until the indicator reads +0.001 to 0.0015 (Figure 6-24).

NOTE
This adjustment preloads the front carriage shaft to
compensate for distortion caused by the heavy spring tension
of the ribbon drive assembly.

41.

Tighten the 2 (10-32) screws that secure the front carriage shaft to the right- and left-hand side plates
to 18 ±2 in/lbs of torque.

42.

Tighten the 2 (8-32) screws that secure the ribbon chassis to the print bar.

43.

Secure the encoder motor to the right-hand side plate with the 3 (8-32) screws and the hex standoffs.

44.

Place the printer mechanism on the cabinet base and secure with the 4 (10-32) screws, lockwashers and
Buna washers. Make the screws finger tight.

45.

Thread the cables and wires down through the slots at the rear of the cabinet.

46.

Secure the stepping motor and speaker wires in the cable clamp. Reconnect the connector to J5 on the
Power Board.

47.

Secure the dc motor and encoder cables in the cable clamp. Reconnect the connector to J4 on the Power
Board.

48.

Dress the cables and wires inside the cabinet and install cable ties as deemed necessary.

49.

Close the rear access door on the cabinet.

6-30

50.

51.

52.

53.

Secure the print head to the carriage with the 4 (6-32) screws and lockwashers. Make the screws finger
tight.

54.

Set the carriage adjustment lever to the minimum gap position (detent closest to the print bar) (Figure
6-5).
CAUTION
It is possible to rotate the carriage adjustment lever beyond

the minimum gap position. If this is done, the correct head gap
adjustment cannot be made.
55.

Tighten the 4 (6-32) screws to 10 ±2 in/lbs of torque.
CAUTION

Do not apply more than the recommended torque when
tightening the print head screws or the moulded inserts in the
carriage assembly may be damaged.
57.

Move the print head to the extreme right or left and check for 0.012 ±0.002-inch clearance.

58.

Replace the ribbon and ribbon spools (Figure 6-7).

59.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.51bs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

60.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

6-31

61.

6.2.5 Carriage Plain Bushing
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Remove the 4 (6-32) screws and lockwashers that secure the print head to the carriage. Carefully lay
the print head aside (Figure 6-4).

Push on the spring-loaded rib bon drive to relieve the tension on the timing belt and disengage the belt
from the dc motor pulley, carriage and ribbon drive pulley. Lay the timing belt aside (Figure 6-8).

Open the rear access door on the cabinet.

Remove the stepping motor and speaker wires from the cable clamp and clip necessary cable ties.
Disconnect the connector from J 5 on the Power Board (Figure 6-12).

Remove the dc motor and encoder cables from the cable clamp. Disconnect the connector from J4 on
the Power Board (Figure 6-12).

Pull the cables and wires up through the slots at the rear of the cabinet.

10.

Remove the 6-32 screw that secures the ground wire to the right-hand side plate. Release the ground
wire and replace the screw in the right-hand side plate.

11.

Remove the 4 (10-32) screws, lockwashers and Buna washers that secure the printer mechanism to the
cabinet base (Figure 6-13).

12.

Set the printer mechanism on the workbench.

13.

Remove the 3 (8-32) screws and hex standoffs that secure the dc motor to the right-hand side plate
(Figure 6-16). Set the dc motor aside.

14.

Remove the two speaker leads.

15.

Remove the 2 (6-32) screws and lockwashers that secure the right-hand side plate to the ribbon chassis
(Figure 6-23).

16.

Remove the two retaining rings that secure the tractor support shaft in the right-hand side plate (Figure
6-23).

6-32

17.

18.

Remove the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate (Figure 6-23).

19.

Remove the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate (Figure 6-23).

20.

Carefully remove the right-hand side plate (Figure 6-23).

21.

Carefully slide the carriage off the two carriage shafts. (place your hand beneath the carriage to catch the
plain bushing as it slides off the rear carriage shaft.)

22.

Replace the new plain bushing in the carriage and slide the bushing and the carriage on the carriage
shafts.

23.

Replace the right-hand side plate.

24.

Replace the two retaining rings that secure the tractor support shaft in the right-hand side plate.

25.

26.

Replace the 1/4-20 screw, lockwasher and flat washer that secure the print bar to the right-hand side
plate. Make the screw finger tight.

27.

Replace the 2 (10-32) screws, lockwashers and flat washers that secure the two carriage shafts to the
right-hand side plate. Tighten the rear screw only to 18 ±2 in/lbs of torque.

28.

29.

Loosen the 2 (8-32) screws that secure the ribbon chassis to the print bar (Figure 6-23).

30.

Loosen the 1/4-20 screw that secures the print bar to the left-hand side plate, then make screw finger
tight. Push the print bar to the rear as far as possible.

31.

Loosen the 10-32 screw that secures the front carriage shaft to the left-hand side plate.

32.

Set up and calibrate the print bar alignment tool (94-11424-2). (Refer to Section 6.2.17.)

33.

Place the alignment tool on the two carriage shafts with the vee slot resting on the front shaft (Figure
6-24).

34.

Slide the tool to the left until it rests against the right-hand side plate. With a plastic hammer, tap the
print bar toward the front of the machine until the indicator reads zero (Figure 6-24).

6-33

35.

Remove the alignment tool and place it on the extreme left-hand side of the carriage shaft against the
right-hand side plate. Again tap the print bar until the indicator reads zero.

36.

Tighten the 2 (1/4-20) ~rews that secure the print bar to the right- and left-hand side plates to 30
±2 in/lbs of torque.

NOTE
This adjustment ensures that the face of the print bar is 2.562
inch from the center line of the front carriage shaft.
37.

38.

Slowly rotate the front carriage shaft until the indicator reads +0.001 to 0.0015 (Figure 6-24).

NOTE
This adjustment preloads the front carriage shaft to
compensate for distortion caused by the heavy spring tension
of the Ribbon Drive Assembly.
39.

Tighten the 2 (10-32) screws that secure the front carriage shaft to the right- and left-hand side plates
to 18 ±2 in/lbs of torque.

40.

Tighten the 2 (8-32) screws that secure the ribbon chassis to the print bar.

41.

Secure the encoder motor to the right-hand side plate with the 3 (8-32) screws and the hex standoffs.

42.

Place the printer mechanism on the cabinet base and secure with the 4 (10-32) screws, lockwashers and
Buna washers. Make the screws finger tight.

43.

Thread the cables and wires down through the slots at the rear of the cabinet.

44.

Secure the stepping motor and speaker wires in the cable clamp. Reconnect the connector to J5 on the
Power Board.

45.

Secure the dc motor and encoder cables in the cable clamp. Reconnect the connector to J4 on the Power
Board.

46.

Dress the cables and wires inside the cabinet and install cable ties as deemed necessary.

47.

Close the rear access door on the cabinet.

48.

49.

6-34

50.

51.

Secure the print head to the carriage with the 4 (6-32) screws and lockwashers. Make the screws finger
tight.

52.

Set the carriage adjustment lever to the minimum gap position (detent closest to the print bar) (Figure
6-5).

CAUTION
It is possible to rotate the carriage adjustment lever beyond
the minimum gap position. If this is done, the correct head gap

adjustment cannot be made.
53.

Tighten the 4 (6-32) screws to 10 ±2 in/lbs of torque.

CAUTION
Do not apply more than the recommended torque when
tightening the print head screws or the moulded inserts in the
carriage assembly may be damaged.
55.

Move the print head to the extreme right or left and check for 0.012 ±0.002 inch clearance.

56.

Replace the ribbon and ribbon spools (Figure 6-7).

57.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

58.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

59.

Replace the printer cover, printer paper and restore power to the LA36.

CAUTION
Before beginning operation, ensure that the carriage
adjustment lever is in the correct position (dependent on the
thickness of the paper).

6-35

6.2.6 Tractor Drive Gear/Line Feed Clutch
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Loosen the 2 (8-32) screws that secure the idler gear assembly to the left-hand side plate (Figure 6-27).

Remove the 6-32 screw and flat washer that secure the line feed knob to the tractor drive shaft (Figure
6-27).

Remove the line feed knob, coupling, the tractor drive gear and the line feed clutch hub from the tractor
drive shaft (Figure 6-43).

Replace the new tractor drive gear and line feed clutch on the tractor drive shaft.

Replace the line feed knob and coupling on the tractor drive shaft and secure with the 6-32 screw and
flat washer.

Tighten the 2 (8-32) screws to 18 ±2 in/lbs of torque.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.7 Ribbon Drive Pulley
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Push on the ribbon drive to relieve the tension on the timing belt and disengage the belt from the dc
motor pulley and the ribbon drive pulley (Figure 644).

Loosen the 6-32 screw that secures the collar clamp and drive pulley to the ribbon drive shaft. Remove
the collar clamp and the drive pulley (Figure 644).

Remove the collar clamp from the defective drive pulley and hand press onto the new drive pulley (front
edges of collar clamp and drive pulley to be coincident) (Figure 645).

Replace the ribbon drive pulley and the collar clamp on the ribbon drive shaft and adjust to give a
clearance of 9/32 inch between the ribbon drive bracket and the ribbon drive pulley (Figure 6-44).
Tighten the 6-32 screw to 6 ±2 in/lbs of torque.

Engage the timing belt on the ribbon drive pulley, push on the ribbon drive and engage the timing belt
on the motor pulley.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

Replace the printer cover, printer paper and restore power to the LA36.

6-36

6.2.8 Ribbon Drive Fafnir Bearing
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Push on the ribbon drive to relieve the tension on the timing belt and disengage the belt from the dc
motor pulley and the ribbon drive pulley (Figure 6-8).

Remove the retaining ring that holds the pushrod in the ribbon chassis (Figure 6-21).

Rotate the ribbon drive pulley until the clutch eccentric is at its highest point (Figure 6-21).

Remove the 8-32 screw; lockwasher and flat washer that secure the ribbon drive to the upper pivot tab
on the left-hand side plate (Figure 6-21).

Carefully remove the ribbon drive along with the pushrod.

10.

Loosen the 6-32 screw that secures the collar clamp and drive pulley to the ribbon drive shaft. Remove
the collar clamp and drive pulley (Figure 6-44).

11.

Remove the 2 (8-32) screws and kep nuts that secure the Fafnir bearing to the ribbon drive bracket
(Figure 6-46).

12.

Loosen the 4-40 set screw that secures the Fafnir bearing on the ribbon drive shaft (Figure 6-46).

13.

Push the ribbon drive shaft toward the rear of the ribbon drive until the shaft clears the ribbon drive
bracket. (Always turn the shaft in a counterclockwise direction when pushing through the one-way
clutch.)

14.

Remove the Fafnir bearing from the ribbon drive shaft and set the bearing aside.

15.

Place the new Fafnir bearing on the rib bon drive shaft and push the shaft toward the pulley end of the
ribbon drive until the Fafnir bearing can be seated in the ribbon drive bracket. (Always turn the shaft in
a counterclockwise direction when pushing through the one-way clutch.)

16.

Secure the Fafnir bearing to the ribbon drive bracket with the 2 (8-32) screws and kep nuts. The kep
nuts go on the outside of the ribbon drive bracket.

17.

Slide the ribbon drive shaft toward the front of the ribbon drive until it extends 1-1/2 inches beyond the
ribbon drive bracket (Figure 6-47). Tighten the 4-40 screw in Fafnir bearing to 5 ±1 in/lbs of torque.
Turn the shaft in a clockwise direction to ensure freedom of movement.

18.

Replace the ribbon drive pulley and collar clamp on the ribbon drive shaft and adjust to give a clearance
of 9/32 inch between the ribbon drive bracket and the ribbon drive pulley (Figure 6-45). Tighten the
6-32 screw to 6 ±2 in/lbs of torque.

6-37

19.

Check that the coils of the backstop spring do not overlap.

20.

Rotate the ribbon drive pulley on the new ribbon drive until the clutch eccentric is at its highest point.

21.

Push the pushrod through the left-hand side plate and engage the retaining stop foot in the left-hand side
plate.

22.

Insert the compression spring between the left-hand side plate and the ribbon drive.

23.

Push the rear of the drive assembly toward the side plate and engage the lower pivot point.

24.

Slide the upper pivot point under the pivot tab on the side plate and secure with the 8-32 screw,
lockwasher and flat washer. Make the screw finger tight.
NOTE
Before pushing the upper pivot point under the pivot tab,
ensure that the flat side of the pivot is resting against the
raised portion of the pivot tab.

25.

Replace the retaining ring that holds the pushrod in the ribbon chassis.

26.

Replace the timing belt on the ribbon drive pulley and the dc motor pulley.

27.

Replace the ribbon and ribbon spools (Figure 6-7).

28.

Rotate the ribbon drive pulley and check the travel of the push rod to either side of center of the
elongated slot in the ribbon chassis. The travel should be equal on either side of center.

29.

30.

31.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

32.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.9 Ribbon Eccentric With Clutch
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Push on the ribbon drive to relieve the tension on the timing belt and disengage the belt from the dc
motor pulley and the ribbon drive pulley (Figure 6-8).

Remove the retaining ring that holds the pushrod in the ribbon chassis (Figure 6-21).

6-38

Rotate the ribbon drive pulley until the clutch eccentric is at its highest point (Figure 6-21).

Remove the 8-32 screw, lockwasher and flat washer that secure the ribbon drive to the upper pivot tab
on the left-hand side plate (Figure 6-21).

Carefully remove the ribbon drive along with the pushrod.

10.

Loosen the 6-32 screw that secures the collar clamp and drive pulley to the ribbon drive shaft. Remove
the collar clamp and drive pulley (Figure 6-44).

11.

Loosen the 4-40 set screw that secures the Fafnir bearing on the ribbon drive shaft (Figure 6-46).

12.

Remove the retaining ring that holds the pushrod in the ribbon eccentric (Figure 6-46).

13.

Slide the ribbon drive shaft toward the rear of the Ribbon Drive Assembly until it clears the Fafnir
bearing, eccentric with clutch and the rear bearing. (Always turn the shaft in a counterclockwise
direction when pushing through the one-way clutch.)

14.

Remove the backstop spring from the ribbon eccentric with clutch (Figure 6-46).

15.

Install the backstop spring on the new ribbon eccentric with clutch. Apply one drop of No. 20 or 30
SAE oil on the spring.

16.

Slide the pushrod into the ribbon eccentric and replace the retaining ring.

17.

With the clutch, eccentric and backstop spring assembled, engage the backstop spring in the clutch
retaining tab.

18.

Slide the ribbon drive shaft through the rear bearing, eccentric washer, eccentric with clutch, Fafnir
bearing and ribbon drive bracket. (Always turn the shaft in a counterclockwise direction when pushing
through the one-way clutch.)

19.

Slide the ribbon drive shaft toward the front of the ribbon drive until it extends 1-1/2 inches beyond the
ribbon drive bracket (Figure 6-47). Tighten the 4-40 screw in Fafnir bearing to 5 ±lin/lbs of torque.
Turn the shaft in a clockwise direction to ensure freedom of movement.

20.

21.

Check that the coils of the backstop spring do not overlap.

22.

Rotate the ribbon drive pulley on the new ribbon drive until the clutch eccentric is at its highest point.

23.

Push the pushrod through the left-hand side plate and engage the retaining stop foot in the left-hand side
plate.

24.

Insert the compressing spring between the left-hand side plate and the ribbon drive.

6-39

25.

Push the rear of the drive assembly toward the side plate and engage the lower pivot point.

26.

Slide the upper pivot point under the pivot tab on the side plate and secure with the 8-32 screw,
lockwasher and flat washer. Make the screw finger tight.

NOTE
Before pushing the upper pivot point under the pivot tab,
ensure that the flat side of the pivot is resting against the
raised portion of the pivot tab.
27.

Replace the retaining ring that holds the pushrod in the ribbon chassis.

28.

Replace the timing belt on the ribbon drive pulley and the dc motor pulley.

29.

Replace the ribbon and ribbon spools (Figure 6-7).

30.

Rotate the ribbon drive pulley and check the travel of the pushrod to either side of center of the
elongated slot in the ribbon chassis. The travel should be equal on either side of center.

31.

To attain equal travel, move the rib bon drive upper pivot point in the direction of the shortest distance
of travel. When travel is equal on both sides of the elongated hole, tighten the 8-32 upper pivot screw to
18 ±2 in/lbs of torque (Figure 6-22).

32.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

33.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

34.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.10 Backstop Spring
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Push on the ribbon drive to relieve the tension on the timing belt and disengage the belt from the dc
motor pulley and the ribbon drive pulley (Figure 6-8).

Remove the retaining ring that holds the pushrod in the ribbon chassis (Figure 6-21).

Rotate the ribbon drive pulley until the clutch eccentric is at its highest point (Figure 6-21).

Remove the 8-32 screw, lockwasher and flat washer that secure the ribbon drive to the upper pivot tab
on the left-hand side plate (Figure 6-21).

6-40

Carefully remove the ribbon drive along with the pushrod.

10.

Loosen the 6-32 screw that secures the collar clamp and drive pulley to the ribbon drive shaft. Remove
the collar clamp and drive pulley (Figure 644).

11.

Loosen the 4-40 set screw that secures the Fafnir bearing on the ribbon drive shaft (Figure 6-46).

12.

Remove the retaining ring that holds the pushrod in the ribbon eccentric (Figure 6-46).

13.

14.

Remove the backstop spring from the ribbon eccentric with clutch (Figure 6-46). Set the spring aside.

15.

Install the new backstop spring on the ribbon eccentric with clutch. Apply one drop of No. 20 or 30
SAE oil on the spring.

16.

Slide the pushrod into the ribbon eccentric and replace the retaining ring.

17.

With the clutch, eccentric and backstop spring assembled, engage the backstop spring in the clutch
retaining tab.

18.

Slide the ribbon drive shaft through the rear bearing, eccentric washer, eccentric with clutch, Fafnir
bearing and ribbon drive bracket. (Always tum the shaft in a counterclockwise direction when pushing
through the one-way clutch.)

19.

Slide the ribbon drive shaft toward the front of the ribbon drive until it extends 1-1/2 inches beyond the
ribbon drive bracket (Figure 6-47). Tighten the 4-40 screw in Fafnir bearing to 5 ±1 in/1bs of torque.
Tum the shaft in a clockwise direction to ensure freedom of movement.

20.

Replace the ribbon drive pulley and collar clamp on the ribbon drive shaft and adjust to give a clearance
of 9/32 inch between the ribbon drive bracket and the ribbon drive pulley (Figure 645). Tighten the
6-32 screw to 6 ±2 in/lbs of torque.

21.

Check that the coils of the backstop spring do not overlap.

22.

Rotate the ribbon drive pulley on the new ribbon drive until the clutch eccentric is at its highest point.

23.

Push the pushrod through the left-hand side plate and engage the retaining stop foot in the left-hand side
plate.

24.

Insert the compression spring between the left-hand side plate and the ribbon drive.

25.

Push the rear of the drive assembly toward the side plate and engage the lower pivot point.

6-41

26.

Slide the upper pivot point under the pivot tab on the side plate and secure with the 8-32 screw,
lockwasher and flat washer. Make the screw finger tight.

NOTE
Before pushing the upper pivot point under the pivot tab,
ensure that the flat side of the pivot is resting against the
raised portion of the pivot tab.
27.

Replace the retaining ring that holds the pushrod in the ribbon chassis.

28.

Replace the timing belt on the ribbon drive pulley and the dc motor pulley.

29.

Replace the ribbon and ribbon spools (Figure 6-7).

30.

Rotate the ribbon drive pulley and check the travel of the pushrod to either side of center of the
elongated slot in the ribbon chassis. The travel should be equal on either side of center.

31.

32.

carriage from the left to right should indicate a pull of no more than 3.5 Ibs (Figure 6·7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.
33.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

34.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.11 Ribbon Drive Rear Bearing
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Push on the ribbon drive to relieve the tension on the timing belt and disengage the belt from the dc
motor pulley and the ribbon drive pulley (Figure 6-8).

Remove the retaining ring that holds the pushrod in the ribbon chassis (Figure 6-21).

Rotate the ribbon drive pulley until the clutch eccentric is at its highest point (Figure 6-21).

Remove the 8-32 screw, lockwasher and flat washer that secure the ribbon drive to the upper pivot tab
on the left-hand side plate (Figure 6-21).

6-42

Carefully remove the ribbon drive along with the pushrod.

10.

Loosen the 6-32 screw that secures the collar clamp and drive pulley to the ribbon drive shaft. Remove
the collar clamp and drive pulley (Figure 6-44).

11.

Loosen the 4-40 set screw that secures the Fafnir bearing on the ribbon drive shaft (Figure 6-46).

12.

Slide the ribbon drive shaft toward the rear of the ribbon drive assembly until it clears the Fafnir
bearing, eccentric with clutch and the rear bearing. (Always turn the shaft in a counterclockwise
direction when pushing through the one-way clutch.)

13.

On machines with serial number 7999 and below, remove the rear bearing by pushing on the bearing to
snap it out of the ribbon drive bracket. On machines with serial number 8000 and above, remove the
retaining ring and push the bearing out of the ribbon drive bracket.

14.

Replace the new rear bearing in the ribbon drive bracket.

15.

With the clutch, eccentric and backstop spring assembled, engage the backstop spring in the clutch
retaining tab.

16.

17.

18.

19.

Check that the coils of the backstop spring do not overlap.

20.

Rotate the ribbon drive pulley on the new ribbon drive until the clutch eccentric is at its highest point.

21.

Push the pushrod through the left-hand side plate and engage the retaining stop foot in the left-hand side
plate.

22.

Insert the compression spring between the left-hand side plate and the ribbon drive.

23.

Push the rear of the drive assembly toward the side plate and engage the lower pivot point.

24.

Slide the upper pivot point under the pivot tab on the side plate and secure with the 8-32 screw,
lockwasher and flat washer. Make the screw finger tight.
NOTE

Before pushing the upper pivot point under the pivot tab,
ensure that the flat side of the pivot is resting against the
raised portion of the pivot tab.

25.

Replace the retaining ring that holds the push rod in the ribbon chassis.

6-43

26.

Replace the timing belt on the ribbon drive pulley and the dc motor pulley.

27.

Replace the ribbon and ribbon spools (Figure 6-7).

28.

Rotate the ribbon drive pulley and check the travel of the pushrod to either side of center of the
elongated slot in the ribbon chassis. The travel should be equal on either side of center.

29.

30.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
. carriage from the left to right should indicate a pull of no more than 3.5 Ibs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

31.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

32.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.12 Ribbon Spool Friction Di!ks
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Clip the three cable ties that secure the speaker wires to the ribbon chassis (Figure 6-25).

Remove the retaining ring that holds the pushrod in the ribbon chassis (Figure 6-25).

Remove the 4 (6-32) screws and lockwashers that secure the ribbon chassis to the right- and left-hand
side plates (Figure 6-25).

Remove the 2 (8-32) screws and lockwashers that secure the ribbon chassis to the print bar (Figure
6-21).

Remove the ribbon chassis and set on the workbench.

Remove the retaining ring that secures the ratchet wheel and the driver spool in the ribbon chassis
(Figure 6-48).

10.

Remove the brake washer, compression spring and the ratchet wheel (Figure 6-48).

II.

Pull the defective disks off the ratchet wheel and the ribbon chassis (Figure 6-48).

12.

Remove the protective paper from the two new friction disks and apply one to the ribbon chassis and
the other to the ratchet wheel. Be sure the friction disks are applied to the right side of the ratchet
wheel. Ensure that the surfaces are free of oil and moisture.

6-44

When you apply the friction disk on the left-hand ratchet wheel, the teeth must be pointing in a
clockwise direction. On the right-hand ratchet wheel the teeth must be pointing in a counterclockwise
direction.
13.

Replace the ratchet wheel, compression spring and the brake washer.

14.

Replace the retaining ring that secures the ratchet wheel and the ribbon spool in the ribbon chassis.

15.

Secure the new ribbon chassis to the print bar with the 2 (8-32) screws and lockwashers.

16.

17.

Replace the retaining ring that holds the pushrod in the ribbon chassis.

18.

Secure the speaker wires to the ribbon chassis with cable ties.

19.

Replace the timing belt on the ribbon drive pulley and the dc motor pulley.

20.

Replace the ribbon and ribbon spools (Figure 6-7).

21.

Rotate the ribbon drive pulley and check the travel of the pushrod to either side of center of the
elongated slot in the ribbon chassis. The travel should be equal on either side of center.

22.

23.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 Ibs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

24.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

25.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.13 Ribbon Spool Ratchet Wheel(s)
1.

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the ribbon spools and ribbon.

Clip the three cable ties that secure the speaker wires to the ribbon chassis (Figure 6-25).

Remove the retaining ring that holds the pushrod in the ribbon chassis (Figure 6-25).

6-45

Remove the 4 (6-32) screws and lockwashers that secure the ribbon chassis to the right- and left-hand
side plates (Figure 6-25).

Remove the 2 (8-32) screws and lockwashers that secure the ribbon chassis to the print bar (Figure
6-25).

Remove the ribbon chassis and set on the workbench.

Remove the retaining ring that secures the ratchet wheel and the driver spool in the ribbon chassis
(Figure 6-48).

10.

Remove the brake washer, compression spring and the ratchet wheel.

11.

Remove the ratchet wheeland set aside.

12.

Remove the protective paper from the two new friction disks and apply one to the ribbon chassis and
the other to the new ratchet wheel. Be sure the friction disks are applied to the right side of the ratchet
wheel. Ensure that surfaces are free of oil and moisture.
When you apply the friction disk on the left-hand ratchet wheel, the teeth must be pointing in a
clockwise direction. On the right-hand ratchet wheel the teeth must be pointing in a counterclockwise
direction.

13.

Replace the ratchet wheel, compression spring and the brake washer.

14.

Replace the retaining ring that secures the ratchet wheel and the ribbon spool in the ribbon chassis.

15.

Secure the new ribbon chassis to the print bar with the 2 (8-32) screws and lockwashers.

16.

17.

Replace the retaining ring that holds the pushrod in the ribbon chassis.

18.

Secure the speaker wires to the ribbon chassis with cable ties.

19.

Replace the timing belt on the ribbon drive pulley and the dc motor pulley.

20.

Replace the ribbon and ribbon spools (Figure 6-7).

21.

Rotate the ribbon drive pulley and check the travel of the pushrod to either side of center of the
elongated slot in the ribbon chassis. The travel should be equal on either side of center.

22.

23.

With the ribbon fully wound on the left spool, the ribbon moving right to left across the face of the
print head and the ribbon grommet starting to pull the reverse sensor to the right, a pull test on the
carriage from the left to right should indicate a pull of no more than 3.5 lbs (Figure 6-7). As a minimum,
the ribbon should be moving right to left across the face of the print head when the pull test is made.

6-46

24.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

25.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.14 Idler Gear

Remove power from the LA36. Remove the printer paper and the printer cover.

Remove the 8 (6-18) screws and flat washers that secure the printer housing to the cabinet base and set
the housing aside (Figure 6-1).

Remove the 2 (8-32) screws, lockwashers and flat washers that secure the idler gear assembly to the
left-hand side plate (Figure 6-27).

Remove the 8-32 screws, flat washers and kep nut that secure the idler gear to the gear bracket (Figure
6-27).

Remove the screw, flat washers and idler tube, from the idler gear and set the gear aside.

Replace the idler tube, flat washers and screw in the new idler gear (one flat washer on either side of the
idler gear).

Secure the idler gear to the gear bracket with the 8-32 screw, flat washers and kep nut. Tighten the
screw to 18 ±2 in/lbs of torque.

Secure the idler gear assembly to the left-hand side plate with the 2 (8-32) screws, lockwashers and flat
washers. Make the screws finger tight.

10.

Tighten the 2 (8-32) screws to 18 ±2 in/lbs of torque.

11.

Replace the printer housing on the cabinet base and secure with the 8 (6-18) screws and flat washers.

12.

Replace the printer cover, printer paper and restore power to the LA36.

6.2.15 Rear Door Bushing(s)

Remove power from the LA36.

Open the rear access door on the cabinet.

Remove the appropriate 3/8-16 screw and bushings that secure the rear access door to the cabinet
(Figure 6-49).

Replace the defective bushing(s}.

Secure the rear access door to the cabinet with the 3/8-16 screws and bushings. Tighten the screw to 18
±2 in/lbs of torque.

6-47

6.2.16 Cover Spring Clips
1.

Lift the cover on the LA36.

Remove the 6-18 screw and flat washer that secure the spring clip to the cover (Figure 6-50).

Secure a new spring clip to the cover with the 6-18 screw and flat washer. Tighten the screw to
5.5 in/lbs of torque.

6.2.17 Carriage Alignment Tool Setup
1.

Place the setting block on the two dowel pins on the base block and secure with the 1/4-20 cap screw
(Figure 6-51).

Loosen the 8-32 butto~ head screw that secures the dial indicator to the base block.

Slide the dial indicator toward the setting block until the indicator needle moves at least 0.015 from its
initial resting point. Tighten the button head screw and set the indicator to zero.

Remove the setting block from the base block.

The alignment tool is now calibrated to obtain a 2.562 inch measurement between the print bar and the
front carriage shaft.

6.2.18 Tractor Gap Adjustment
With the tractor cover closed, there should be 0.025-0.030 inch clearance between the raised portion of the tractor
cover and the stripper plate. To attain the desired clearance, open the tractor cover and with a pair of pliers carefully
bend the adjusting tab (Figure 6-52).
6.2.19 EIA (DFll-A) Interface
1.

Remove power from the LA36. Remove the printer paper.

Open the rear access door on the cabinet.

Disconnect the EIA connector from the transmission media.

Disconnect the connector from J4 on the Logic Board (Figure 6-53).

Remove the 2 (8-32) screws, lockwashers and flat washers that secure the EIA interface bracket to the
cabinet base (Figure 6-53). Set the EIA interface aside.

Secure the new EIA interface to the cabinet base with the 2 (8-32) screws, lockwashers and flat
washers.

Reconnect the connector to J4 on the Logic Board.

Reconnect the connector to the transmission media.

Close the rear access door on the cabinet.

10.

Replace the printer paper and restore power to the LA36.

6-48

2 (6-18) SCR EWS
(HIDDEN)

COVER
2 (6 -18) SCREWS
(HIDDEN)

2 (6-18) SCREWS

2 (6-18)
SCREWS

CP-1559

Figure 6-1 Housing Removal

6-49

CONNECTOR

CONNECTOR
7393-16

Figure 6-2 Power Board Connectors

6-50

CLAMP
7393-04

Figure 6-3 Ribbon Cable Clamps

6-51

PRINT HEAD

4(6-32)
SCREWS

CARRIAGE
ASSEMBLY
7037-05

Figure 64 Print Head Removal

6-52

CP-1552

Figure 6-5 Carriage AdjustmentLever

6-53

PRINT BAR

PRINT HEAD

0.012
FEELER GAUGE

6-32 SCREWS TO
BE TIGHTENED 10 ± 2
IN./LBS. OF TORQUE

CAUTION
ENSURE THAT FEELER GAUGE IS INSERTED
BETWEEN THE PROTRUSIONS ON THE
PRINTHEAD. FAILURE TO DO SO WILL RESULT
IN IMPROPER CLEARANCE AND SHORTEN
THE LIFE OF THE PRINTHEAD.
7393·06

Figure 6·6 Print Head Adjustment

6-54

RIBBON

RIBBON
IDLER

SPOOL

PRINTHEAD

DOD

,~~IIl: 111; iIf"l'llI! 1Il";1II •

ur m:1II ~ til J III II[ ;;lIf~lI~:A'JI["'l1

.1 '" II Q

11 ulill 11f 0 Iii p 1111 III niT '~Ifo'"
o

o
o

RIBBON
IDLER

RIBBON
IDLER
CP-1554

Figure 6-7 Ribbon Threading/Drag Test

6-55

4(6-32)
SCREWS

PUSH
TO RELIEVE
BELT TENSION

RIBBON DRIVE
PULLEY

DC MOTOR
PULLEY

TIMING BELT

CP -1560

Figure 6-8 Timing Belt Removal

6-56

(8_32)~O

SCREWS ~

(8-32)

SCREWS

CP-1558

Figure 6-9 Keyboard Bezel Removal

6-57

KEYBOARD BEZEL - - - - /

\I
STANDOFFS

, ..._ _- - - - - LK02 KEYBOARD

__J------:;?"

8- 32 KEP NUTS

J2 CONNECTOR

Cp-'567

Figure 6.10 LK02 Keyboard Removal

6·58

KEYBOARD BEZEL ---~

HEX STANDOFF

LK03 KEYBOARD

8-32 KEP

NUT

CP-1566

Figure 6-11

LK03 Keyboard Removal

6-59

POWER BOARD

RIBBON CABLE

J6
CONNECTOR

J1
CONNECTOR

CONNECTOR

J5 CONNECTOR

J3 CONNECTOR

7393-16

Figure 6-12 Power Board Connec tors

6-60

10-32 SCREW

PRINTER
MECHANISM

10-32 SCREW

o u
o
10-32 SCREW

10-32 SCREW
cp- 1562

Figure 6-l3 Printer Mechanism Removal

6-61

o
REFERENCE HOLE

--I-.'I''tI

~~~I~a;~~~~~~~=~~~~~~~§~~~~~.+--H~~

COINCIDENT
WITH
CIL OF
FRONT
FACE OF
PRINTBAR
REFERENCE HOLE

CP-1561

Figure 6·14 Printer Mechanism Alignment

6-62

0_020 IN_ CLEARANCE
BETWEEN FACE OF
CARRIAGE ASSEMBLY
AND BENT-UP FLANGE

0_020
FEELER GAUGE

BENT-UP
FLANGE

CARRIAGE ASSEMBLY

7393-13

Figure 6-15 Printer Mechanism Adjustment

6-63

RIGHT HAND

DC MOTOR

8-32
SCREW

HEX
STANDOFFS

7393-12

Figure 6-16 DC Motor Removal

50%-----t

Figure 6-17 PTl or PT2 Waveform

6-64

PHASE ADJUSTMENT SCREWS

Figure 6-18 Encoder (Rear View)

f r

1.4 DIV. MAX. JITTER
CP -1622

Figure 6-19 Encoder Jitter

6-65

I
I

CHANNEL 1

I
I

90· LEAD

I
I
CHANNEL 2

I
I

I
I
I

I
I
I
I

I
I

I
I
I

I
I

I
I
I

I
I

I
I
I
I

I
I

I
I
I

I
I

CP-1620

Figure 6-20 PTl and PT2 Waveforms

PUSHROD
RETAINING RING

CHASSIS

RAISED PORTION
OF PIVOT TAB

COMPRESSION

90 ANGLE

SCREW

TAB

TAB
7393-10

Figure 6-21

Ribbon Drive Removal
6-66

CENTERLINE OF
ELONGATED HOLE

PIVOT TAB

RIBBON DRIVE
PUSHROD

8-32 UPPER
PIVOT SCREW

UPPER PIVOT POINT

RIBBON DRIVE PULLEY

DOD

o
o

o
NOTE:
Travel of push rod to be equal on both
sides of the elongated hole.

CP-1565

Figure 6-22 Ribbon Drive Adjustment

6-67

PRINT BAR

RINGS

SCREW
RIGHT HAND
SIDE PLATE

RIBBON CHASSIS

6-32
SCREWS
7135-04

Figure 6-23 Carriage Removal

6-68

TAP WITH PLASTIC HAMMER
UNTIL INDICATOR READS (1)

8-32 SCREWS

TAP WITH PLASTIC
HAMMER UNTIL INDICATOR
READS (1)

PRINTBAR

1/4-20 SCREW
HIDDEN
1/4 - 20 SCREW
HIDDEN
LEFT HAND
SIDE PLATE
RIGHT HAND
SIDE PLATE
10-32 SCREW

10-32 SCREW
o

ALIGNMENT
TOOL

DOD

FRONT CARRIAGE
SHAFT

PRINTBAR ALIGNMENT

8-32 SCREWS

PRINTBAR

RIGHT HAND
SIDE PLATE

LEFT HAND
SIDE PLATE
10-32 SCREW

10-32 SCREW

JU-1i.~t;~~!i~~~=={:t= §-------.-II"
ROTATE SHAFT TO
H-------::;;.~=---------- OBTAIN +0.001-0.0015
READING
ON INDICATOR
o

ALIGNMENT
TOOL
o

o0U

a
o

o
o

PRINTBAR PARALLELISM
CP-1557

Figure 6-24 Print Bar Alignment/Parallelism

6-69

RETAINING
RING

8-32
SCREW

CABLE
TIES

RIBBON
CHASSIS

6-32
SCREWS
7393-3

Figure 6-25 Ribbon Chassis Removal

6-70

7393-15

RIBBON DRIVE
SHAFT
BACKSTOP
SPRING

ECCENTRIC

PUSH ROD

REVERSE
SENSOR

RAT CHET

INTERPOSER
BAIL CAMMING
FOLLOWERS

PAW L

CLEARANCE MUST BE
WITHIN 0 .020 INCH
OF OPPOSITE SIDE

CP-1555

Figure 6-26 Ribbon Drive Adjustment

6-71

IDLER
GEAR

8·32
SCREW

LINE FEED
KNOB

6·32
SCREW

0.002·0.007 INCH
BACKLASH AND
EQUAL DEPTH
PENETRATION

LEFT HAND
SIDE PLATE

7393·10

Figme 6-27 Idler Gear Removal

6-72

LEFT HAND
TRACTOR

6-32
SCREW

RETAINING
RING

RETAINING RING
AND FLAT WASHER

RETAINING
RING

7393-4

Figure 6-28 Tractor Removal

6-73

7/8"----4~

LEFT-HAND
SIDE PLATE

TRACTOR
FEED PIN

7393-14

TRACTOR ADJUSTMENT

TRACTOR
BUSHING

RIGHT HANO
TRACTOR

TRACTOR

PHASING

Figure 6-29 Tractor Phasing/Adjustment

6-74

STEPPING OOTOR {

SPEAKER {

~/
~
CP -1569

Figure 6-30 Stepping Motor Connector (15)

6-75

STEPPING MOTOR

(8-32) SCREWS

(8-32) SCREWS
7393-3

Figure 6-31

Stepping Motor Removal

6-76

+5V

GND

LOGIC BOARD
(M7722

LOOP CABLE TIE
OVER STANDOFF
BEFORE SECURING

SCREW

SCREWS

7393-8

Figure 6-32 Logic Board Removal

6-77

SCREW

SCREW
7393-16

Figure 6-33 Power Board Removal

6-78

6-32

QUICK

c--_ _ FAN

SCREWS
7393-2

Figure 6-34 Fan Removal

6-79

FAN QUICK
DISCONNECT

115V - 230V
JUMPER(J1)

FUSE MTG
BRACKET

TRANSFORMER(T1 )

8-32
SCREW

7393- 16

Figure 6-35 Transformer Removal

6-80

CAPACITOR C5

FUSE (F1)

WIRE

BRACKET
7393-7

Figure 6-36 Capacitor C5

6-81

LK02
KEYBOARD

SWITCH (S1)

REMOVE
THESE TWO
CONNECTORS
7393-11

Figure 6-37 Rocker Switch Sl

6-82

8-32
RIBBON

PRINT BAR

1/4-20

7393-10

Figure 6-38 Print Bar Removal

6-83

RETAINING
RING

6-32
SC.REW

TRACTOR
SUPPORT
SHAFT

LEFT HAND
SIDE PLATE

TRACTOR
DRIVE
SHAFT

LINE FEED
KNOB

LEFT HAND
TRACTOR

o
o
RIGHT HAND
TRACTOR

RETAINING
RING
CP-1564

Figure 6-39 Tractor Drive Shaft Removal

6-84

LINE FEED
CLUTCH

TRACTOR
DRIVE SHAFT

KNOB

6-32
SCREW

7135-12

Figure 6-40 Line Feed Clutch/Knob Removal

6-85

LEFT HAND
TRACTOR

SCREW
HIDDEN

RIGHT HAND
TRACTOR

SCREW
SHAFT

RIGHT HAND
SIDE PLATE

RETAINING RING

SHAFT

7393-4

Figure 641 Tractor Suppert Shaft Removal

6-86

LEFT HAND
SIDE PLATE

10-32
SCREW

CARRIAGE
SHAFTS

7135-12

Figure 642 Carriage Shaft Removal

6-87

LINE FEED
KNOB

SQUARE
DRIVE SHAFT

TRACTOR
DRIVE GEAR
AND
LINE FEED
CLUTCH

6-32
SCREW

7393-14

Figure 6-43 Tractor Drive Gear Removal

6-88

PUSH IN THIS
DIRECTION TO ,
REMOVE
TIMING BELT

RIBBON DRIVE
PULLEY

COLLAR CLAMP

6-32
SCREW

TIMING BEL T

7037-5

Figure 644 Ribbon Drive Pulley Removal

6-89

o
FRONT EDGE OF DRIVE
PULLEY AND COLLAR
CLAMP TO BE COINCIDENT

o
o

COLLAR
CLAMP

6-32

RIBBON DRIVE PULLEY

SCREW
CP-1563

Figure 6-45 Ribbon Drive Pulley Adjustment

6-90

RIBBON DRIVE SHAFT

RIBBON DRIVE BRACKET

o
o

o
o
COLLAR
CLAMP

RIBBON DRIVE
PULLEY
CP-f570

Figure 6-47 Ribbon Drive Shaft Adjustment

6-92

ECCENTRIC

COMPRESSION
SPRING
FRICTION
DISKS

RETAINING
RING

CP-1707

Figure 6-48 Friction Disk/Ratchet Wheel Replacement

6-93

7393-08

3/ - 16 SCREW
8

REAR

DOOR

~-.............

CP-1556

Figure 6-49 Rear Door Bushing Replacement

6-94

_ _ _ _ _ COVER

6-18 SCREW

HOUSING
CP-1553

Figure 6·50 Cover Spring Clips

TIP OF INDICATOR
TOUCHING SETTING BLOCK

SETTING BLOCK

DIAL

INDICATOR - - - - l . . . - i ' , {

2.562

B -32 SCREW FOR SECURING
INDICATOR HIDDEN UNDERNEATH
BASE BLOCK

BASE

INCH

BLOCK

Cp·1568

Figure 6·51 Carriage Alignment Tool Setup

6·95

0.025-0.030"

CLEARANCE

STRIPPER
PLATE

TRACTOR
COVER

CP'1635

STRIPPER PLATE

ADJUSTING TAB

TRACTOR COVER

Figure 6-52 Tractor Gap Adjustment

6-96

EIA (DF11-A)
INTERFACE

CABLE TO
TRANSMISSION MEDIA

7393-9

Figure 6-53 EIA (DFII-A) Interface

6-97

CHAPTER 7
ENGINEERING DRAWINGS
AND MATERIAL LISTS
This chapter contains two Customer Print Sets for the LA36. The following drawings are included for DECwriters with
serial numbers 21932 and lower.
Title

Drawing No.

LA36 Option Arrangement
LA36 Power Schematic
LA36 Logic Board
LA36 Power Board
LA36 Encoder PC Board Photo transistor
63 Key Keyboard Assembly
LK02 Keyboard
11 Key Keyboard Assembly
11 Keyswitch Array Module

E-AR-LA36-0-1
D-CS-LA36-0-5
D-CS-M7722-0-1 (8 Sheets)
D-CS-5410805-0-1 ( 5 Sheets)
D-CS-5411049-0-1
D-UA-LK02-0"0
D-CS-5410736-0-1 (2 Sheets)
D-UA-LK03-0-0
D-CS-5410819-0-1

The other print set is for DECwriters with serial numbers 21933 and higher (option upgradable models).
Title

Drawing No.

LA36 Power Board
LA36 Logic Board
LA36 Encoder PC Board
63 Key Keyboard Assembly
LK02 Keyboard
14 Key Keyboard Assembly

D-CS-5410805-0-1 (6 Sheets)
D-CS-M7728-0-1 (9 Sheets)
D-CS-5411049-0-1
D-UA-LK02-0-0
D-CS-5410736-0-1 (2 Sheets)
C-UA-LK03-A-0

Signal Glossary Table for M7728 Logic Board.

7-1

COPYI<IGHTq:)1974 DIGITIIL
EQUI PME.N7 CORPORIITION

A/OTES:

======

REF

x-Y COORDINIlT£ HOLE LOCIIT/ON K-CO-5411f)49~

REF

.IISSY/ORILLING HOLE LAYOUT

O-IJH-{i411f)49~-5

I?E/'

MOOULE ECO HISTO~Y

8-MH-54/f1$49-G-6 3

ReF

ETCHED CIRCUIT BOARD

D·/A· Sf;lrn'Jd'()'4 4-

RI, R2.

PO T{;.N TI o METER 10K

13091'30-12-

Qi, Q2.

PHOTO TlUINSISrOR.

151190,"

.750
REF

t
-+

~~EI
o

L'~ORJ

G
--It-

TRIM TO .03 MAX

~(IJ

'-=I
0

I
.0)
~~

p.T. COLL. 1

+5v

AT CaLL 2
RI

POT
10K

L[)

POT

~
~

10K

I"-

B
QI

I--

:>..

QTY

DESCRIPTION

REF DESIGNATION

PART NO.

ITEM
NO.

PARTS LIST
ETCH BOARD REV

1B 1

III

~~~~~~~-~77~ ENCODER
PC BOARD
PHOTOT RANS
1STOR
~==3===E==I==3Ip~m~.:~~.
PRo"-:?P.
ID~~~'7*
NEXT HIGHER ASSY

ti;;s

~tI>.u~

DEC NO.

EIANO.

DEC NO.

EIANO.

SEMICONDUCTOR CONVERSION CHART

SCALE;'
SHErr

DeS 5411049-0-1
B
DIST. j
1. 1. 1. j 1 1 1 1 1

1~~=~~NO'--8----~I------7----~I------6----~I~--~5-----'tr-----4-W~~~I~~~3--~~r-I--~~2~~~.TI~~~1~~
OF /

7-1

3
NOT·E.S,
I. ALL

SEE

TABl.E

HARDWARE

NECESSARY

TO MOUNT IIEM·
AND
ITE.M .. 3
IS SUPPl.IED 1101
THE OPTIONS KIT.
2.. ITEM "I IS INSTAl.Ui.O SY
INSeR.TING THE SEN,. ENDS
OF THE "PAPER. eASK~T' INTO
,HE 2 HOl.ES PROVIDEC ON

NOIE "'2.

r------j~;:;;::;::;::;::;::~:;~r_----~~=i~~~~~~~=-~~~UOVER

TOP (REF)

AS SHO~.

-----

FLAT WASHER

9006664
TABLE

SUPPOR.,.

BRK, (REF)

"10-32 x .75 LG.
SCREW, PAN. HD MACH
NYLON

9006075-1

PUSH-IN NUT

(900%11)
,.ABLE TOP

(341173~)

----- - -- ----- --- ----l-------NOTE . ,

'10-16 X.75 LG. SCREW
TYPE B SELF THO.
(9009612-01)

FLAT WASHER

(9006664)

TABl.E SUPPOR, BRKT
(C-MD-74I1S7Z - b -0)

VIEW A-A
SCALE: 1/1

B
SEE NOTE·,

-PI. -7009

"'5;'6 SPLIT LOCK WASHER
(900<;;';92')
FI STUSI!OONOPTIO

97-·12) 3

-'::7~~ ~. -

'mfG.

LA36

"'5;', -18 x .75 l.G
SCREW

HEX HD CAP
('=>00<02.55-9)

7-3

8
This dfIW.inl.lnd.IPKiflcatlonl, h.,.!n, Ire tl'lt proPJ
Irty of Dilittll Equlpmlnt Corpo,.tlon Ind ,hili not be
reproduced or copitd or uMd In who" or in Plrt ••
tile Mli, for thl mlnufKture or .... of item, without

NOTE:5:

written perm".,on.

KBS2-

1. FUSE Ff IS 2.A 58 FOR 115V AND
7A SB FOR 230 V
2. POWeR CORD COLORS ARE AS FOLLOWS:

COPYRIGHTC!;) 1974-, OIGlrfil..
EQUIPMENT COR PORRTION

VOLTAGE
GND
NEUTRAL
HOT

FUNCTION SWITCHES
KEY
HH

BOI'IRD LK¢c
5 X i!.
/~~~--'I'

230 V

115 V
GRtE.EN
WHITE
BLACX

:=t

.---------------~

KBS3

~
~

PRINT
MECHI'IAj 15/V1

GRN/Y£L

;[lGRN

BLUE.
BROWN

D
81'15£

+-12V

+5V
LOGIC BORRD
M77Z2

<.II

GND

I , 9 6 7 9 1/ 12/6 3//9 23ZH33435 J5

+sv

DF II

6ND
-/2V

IF USED

(y-'L'C(IDiYYYYYYY'

(JJ U Lll UJ 1J

~
!);i

~
€V

;~~Njo~ff;g:r---- ~ ~~~~G£r---------~R~E~D~--t=;77~J--~-t------~t--------llI---'t---------t------t--------------------------------------~~--~
I-0 ~;T ;£;;5~~
m
! DC. ~<5~;.:;~c..;K---I-~;9 J4
GND
+SV
L
--- - - - -

PM.

1..:-'- f--~ I -

__ 1 _ _ _ _ _

ENCODER (')..

GND

LED SINk

'-.../

L__~::~================~~~2ITIV~==~~ C2

L-____________________________
L-----------------------------~~---r~
____1_7 RZwe
~+=ZI~V

ll:==~~~~~~~~~~~~~~~~~~;+~2~I~V~~~F2
+ZIV
;;z

POWER BOI'lRD
5410805

L~==========================================~+SZIT2v====+=~ ~2
EZ

+ZIV
P2
L====================================~~~=t°Z

l__~~=======================================================+~Z~/V~==:f=! Me

7 8

" ."

~ 23(!JV COMNECTION ONLY

I/S CONNEcnON ONLY

RED YEI..

B
RED

I
I
I
I
I

LFI
NOTE

1/6/.?3¢V-~
47-63Hi!.-

e.
HOT

\
)

NOTE

8LK

NeUTRAL

_l....-/~_G=-N..;.;D::....-____~..,

LF3
'---rh-r-L-F,------o

VIO

k851

LF4

R£D!VEL

I
I

RED

I
I
I
1

WHT

2.£"1

J..F2

POWER
5 WITCH

u-6o..-____-,

-f-J "'

...

FRN
f 15V

Ii "---+-------==-=---_ _ _ _

BLI<

5¢ /6¢ Hi!.

----J

WHT

.r/

r------7,,,,>-B_L_K_ _

--....J

OTY

REF DESIGNATION

DESCRIPTION

PARTS LIST

1 1

I J

liTEM

PART NO.

INO.

~b~~~~NO·--8----~I----~7~--~I------6~----r-I----~----r---mu~~~~~==~3~==~I=-~~2~~~1~~~1~,~~
SEMICONDUCTOR CONVERSION CHART

SHEET

OIST.

I 1

I J1 I J

7-4

NOTES:
t.

1-----------' 2.

JI .,JZ -

3. PREFERRED CONFIGURATION

ell POWER

18 IG 18

8887 .........

I .............

E6S'EMPTY

ESa-EMPTY

E6~1

E65

E58

9
~

* ~91
J IB I6
2l1~~cN ~ ~ +~1f4 m ~

1'2

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REF DESIGNATION 1
ETCH BOARD REV ISIC '1 l' T T I

I PART NO.

OTYI

I~~

;" v

FIRST USED ON OPTION MODEL

LA36

EM
rTNO,

PARTS LIST

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DEC NO. EIA NO.
DEC NO, EIA NO,
IDICSIM7722-0 I
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REF
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CAP saoF 2SV 101 ,.,,\.. £\..
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DIODE 0884
DIODE IN748A 3S\f fENER 51
DIODE IN748,. 3:51 fENER 51
DIODE IN4004
DIODE .411 5. IAlI S.IVUNER IS
CONN 8P1N IlAT·N-LOI(SDCKET HOUSltlG)
CONN 4UPIN BERG
RES SII I/~

l.lIH'5
1"1'79(0
11 .. 113
11 ••114
11.8122
1114861
1115781
1105873
121834.
12.8841
IWla411

RES IK III 51

IS\6959S
13••2.2
13•• 221
1388258
13·1295
1300365

RES 1.51 lit 51
RES 10K %I 51
RES liD III 51
RES •• K lit 511
RES 820 %I 51
RES 5.61 %I 51

138.391
13.8479
13.1322
13.1327
1381775
1381174

RES 10011 III 51
RES '4.71 III IS
RES IK %I IS
RES I~ IW 5",
RES 3 .481 ~I I"
RES 121K %I IS
RES 232K %I IS
RES 30.U %1 IS
RES 59K '" IS

13,2466
13.2941
1383114
1381&:'(08
13.5114
13.5255
1385424
131159413005'15

TRANSISTOR MPSASS
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1518715

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ASSYIIIRILLI. HOLE LAY.T
IIOIIULE ECO HISTORY
ETCHED CIICUIT 80ARD
C82
ClI,cal,C72,C71 C19
CI THRII C84 .ell,ClI,C74,
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PARr NO. ('~

OESCRIPTION

REF DESIGNATION

I
3

RI5
R9,RIO
RI7
RI6

Q7,Q8

10
I

02,04,Q8,OlO,Ol I ,012.013
Q3,05,Q8
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II ~ I 1-0::~211 ~~I9J 2 I

PARTS LIST
QUANTITIES SHONN REPRESENT PREFERRED CONFIGURATION

;:'~O:;OAl,-===-~ ::

SMML NOr . . . . . . . . aa COMO. VIm" WMCU

OlINMtTASMIASIS"'M~OIIoN.I

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330 kW S"

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REF DESIGNATION

E2.n .E4,E5 ,EI ,E24 ,EIO ,Elt,
EII,E60. £!of.
Ell ,EI2,E2I,En,MO,EII

r.
2
I
a
2

12
13
14
15
16
17
18

-27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45

E23
E21, £5'
E13,E28

I HS147

Ie 1474

IHSl7S
1181171

IC 74"
IC 7411
IC 7421

...5177
198158e

IC 74'1
,e 748"

1O E7 ,EIO,EII,E20,E21,E41 ,Ut
ESt.,EI2.,E81
l. E440,E46
I E8
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I E6f.
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2 EI5,E31
3 EI,E34,U5
3 E22, ESG, E57
I E6...
I E5S
2 EI:',E68
2.. EI4, ESI!
E28
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8
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20
21
22
23
24
25
26

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PART NO.

DESCRI PTION

1"."4

IC 7414

18'''81

IC .74154
18'871\
188....
Ie 7413
Ie 74183
181""
1818848
It 7442
Ie 1437
18".81
1818895
IC 74198
1118153
Ie 74150
1818282
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It 7489,310 I
181'396
18 t 8436
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1118458
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1918858
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1818851
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II
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13
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E58

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51
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81
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17
61
68
70
71

72
73

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i21i!1,"93
12100541211595
1209456
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IC ,.IN LOCATIONS
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SEMICONDUCTOR CONVERSION CHART
1 1 1 I 1 1

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Iitt II-O-<;;2~9Ivg 1~~,2sl 2 I

"THIS DRAWfllIG AND SPfCIFfCATIONS. HlRIIN, ARE THE
PROPERTY OF DlGfTAL EQUIPMENT CORPORATION AND
SHALL NOT II RPRODUCID OR COPtED OR USED IN WHOLE
OR IN PART AS THE WlS FOR tHE MANUFAC'n.IM OR SALE

~=:51f71~~~~ CORPOAATION"

QTY

REF
REF

PART NO.

QTY

REF DESIGNATION

1
2

RS8 R86, Fl89
RB,RI3,R20,R27 ,R34,R41,
R48

RES. 2K 1/4. 51
RES 2.7K,~',5S

1302388
1300428

R94,R8I,RI18 ,R117 ,R122

RES 3.8K,~W,51

1300444

R5,R7 ,RI2,RI5,R18,R21,
R28 , R28 ,R33 ,Rn , R40 , R42
R47 ,R48,R88, 11.<0.,
R78,R78 ,R73,R72,R81 ,R57,
Rl08,Rl08,Rll0

RES 4.7K,%W,5S

1300447

RES 10K,~W,5S

1300479

R8 ,RI4,R22 ,R28 ,R38, R43,
R50
R120

RES

18K,~W

1302485

RES 580 %W 51

1301880
1311845

K·CO·5410805·0·,

ASSY/ORILLING HOLE LAYOUT

I·AH·541080S·0·5

REF

IIODULE ECO HI STORY

8·1IN· 541 0805-0-1

ETCHED CI RCU I T BOARD

5010808

CAP 211UF 25Y 10"/. "'I.. lil..
CAP ,OOSUF IOOV Z,fl"/. DISC

1000075

cCll,C17 ,C18

Cl THRU C7
C13,C15

1
2

10011"5
1001810-0'
1000037

CAP .0IUF l00Y 201 DISC

C14

CAP .22UF 100V lOS MYLAR

C8
C8,Cl0
Cll,C12

CAP 180UF 12Y 20S AL EI..
CAP 20UF SOY 10$ AL lil..

•

8
7'
8

1009433

9
10

1002839

7
5
18
8
7
1

CAP 1.IIUF 35Y 10·'. T"'~"'t'
DIODE 0884

1009725

1100114

Dl THRU 04,07 THRU Dl0,D12
THRU 015,017 THRU DZO,022
THRU D25, D27 THRU 030, D32
THRU D35

oIODE IH~144

11 05648

2
1
I

D37, D46 THRU D51

DlODE IN4004

1105796

4
1

DIODE IN4721
BRIDGE

1110182
1110714

15
16

D59 THRU D82
D58
D71,D72,038,D39,063

4
1
4

Jl
J2,J3,J4,J5

05,D8,011,DI8,02Pl,
D38 ,D40 THRU 045
;
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25
2.

S.IV I'f. ~fNER

1105873

Itf1!1MIS PI..UGS

121\S~S

CONN 3M 40 PI I-l
CONN MAT·N·LUCK SOC\(E, \-lOUSING

1210073
1209340

SOCKETS (PC) AMP (61!.2()-1)

1209456

19
20
21

5510831
c1301895

CONN H802 18PIN (IIODIFIED)

Rill

RES 47 ,lsi, 5"

7
2

Rl ,RSI ,R52,R53,R54,R55,R58
Rll1,R112

RES ·0.50 ZW 11RES 4 5. W.W.

1'3lf_7

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RES 100, %W 5"

TRANS 2.1ol:'111C

15030"-~

9 1<l~,Q6,Q8QI~OI2.Q"',~Q391 TRANS 65318
2
042,043
TRANS 3715
1
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TRANS 2N3791

1509338

1503068

61
62

033,034,036,
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,026

TRANS MPSA05

1510705

all,as ,a, ,09,011,013,
aIS, Ott, 025, 027 ,035, 037,

TRANS MPSA55

1510706

TRANS D44C8

1510421

TRANS t>4SC!)

1510598

I C LM309K REGULATOR

1910460

1509581

1t0f'6.'46,Q5~

,Q41,Q49

HEAT SINK

14-11071

FUSE C:LI?S

9009513-0\

69
70

8
8
I
2

WASHERS, I"I..A', loly\..O~ .... 10
EYELET (MA.i-N-1..01<)

9006701
9007266

71
72

FUSE 30AMP 32V GLASS
FUSE. lAMP SI..OW SI..OW

90072'10
90072.12.

73
74

2.
Z4
34

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~oo9000

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1

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90oroS60

Rl04,RI05,R81,RI13
Rl03,R97

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1310597
1300250

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29
30
31

1301475

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130027 i

R75,1I"
R74,R7.

1
I

32
33

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f300~0

Rao

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1-S09639
1301972

1171

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1301864

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El

Fl,
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37
38

CABLE; POWER LJOAIU)
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1309855

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IZ,
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1300309

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13031162

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1~6

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(300291

AR
2 'RA4.1Ri!7
2 ID52.....

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IS00a65

43
44

R83,R64

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1300364

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1301320

-I

,to

-SEE NOTE 4.

;'0
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9009597
84
85
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1300228

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7 113,c
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1302.951
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1300229
1302124

c54
55
56
57

1305126
1302956

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r--

24
25

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~2.\

47
48

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NO.

2
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PART NO.

RES 619,%W 1%
RES 196,%W 1%
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Rll~

Rl07

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DESCRIPTION

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R59

2S
1
1

1
1
4

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R98,Rl02

DIODE .41 5.IAi'

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ITEM
NO.

X·Y COOROINATE HOLE LOCATION

2
1

....

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REF DESIGNATION

10:'

!NSUL,Il."'t'OR
COMPOUI\lO, II-\E~MAI..
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87
88
89

91074>88
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9006012 ~Ol
1510707-00
1570708-00
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SHALL NOT IE REPRODUCED OR COPIED OR USiD IN WHOLE
OR IN PART AS THE lAStS FOR THE MANUFACTURE OR $I\LI!
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2
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8
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3
NOTE.~:

th. bu., for the m.nuf.cture or .... of item. without

."tt," permission

ICOPYRIGH~~, 1974, DiGITAL

EQUIPfIIENT CORf'!.l'lATION

\4'SC'1

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DIA

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DESCRIPTION

REF DESIGNATION

FIRST USED ON OPTION MODEL

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TITLE

KEYSWITCH
ARRAY
MODULE
b""",;"':':''':':''''':''':''''-;:;;;;iirnF-';'''''-,---;;;'iI1
SIZElcOD~1

DEC NO.

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DEC NO.

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SEMICONDUCTOR CONVERSION CHART

SCALE

-+---I--

SHEET

NUMBER

RSEV.

0 Ie SI 54 108 19 0 1 1 1
DIS!. 1 I
1 1 1 1 J

1
7-23

''THIS DRAWING AND SPECIFICATIONS, HEREIN, ARE THE

NOTES:

PROPERTY OF' DIGITAl EQUtPMENT CORPORATION ANO

SHALL NOT BE REPRODUCED OR COPIED OR USED IN WHOLE
OR IN PART AS THE BASIS FOR THE MANUFACTURE OR SALE

ro~~~ir7r,4.R~Tcr,\~;~~:~~~

CORPORATION"

COAlAl£CTORS,

11/ -

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FILTER C!'IPS
i;.rNE .VOL rAGE
ENCODER ~ CIiRRlflGE MOTOR
J5 - LIME FE1i.D MOTOR
.1G - HEllO CI9BLE
2. COMPOUND (ITEM 85) TO BE USED 0/./ BOTH SIDES OF ALL
INSULATORS(ITEMS 83e;' 84) IWD D58.
.1Z .13 .14 -

3. 'THIS SIDE up. STICKER TO BE:
INSTALlED ON CABLE CONNECTOR

-..-.....--_.-t

PI AS SHOWN.
4. IF SERVO MOTOR IS NOT FUSED
EXTERNAlLY ON CABINET,THE
VALUE OF FI WILL BE 2AMP,
SlOW-i3LOW. C% 9007216).

5. RESISTORS RI20ANDRI21

1'-

/
/

ISo"'} I:EF

/
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TRANSISTORS AND

/ /1

~TYp. 4-40 HDWR-ALL
\

85
79
80

I ON H.S.

32 HD77

ARE TRIM~E~ RESISTORS
WHICH W..A.Y BE REMOVED
IN TEST. IFA RESISTOR IS
REM-OYED IT MUST BE

85
8,3

RE!/\ovrD C<1MPLETE.LY.

ID.le

REF

At-------+--+--t
Ie TYPE

GND

+ sv

7-25

8
"TH~S

DRAWING AND SPECIFICATIONS, HEREIN, ARE THE

I I A1,i.!I-O- g2~91 Vg 1~~32,1 2 I

PROPERTY OF DIGITAL EQUIPMENT CORPORATION AN~
SHALL NOT BE REPROOUCEO OR COPIEO OR USED IN WHOlE
OR IN PART AS THE BASIS FOR THE MANUFACTURE OR SALE

g6~~:~~~~~~74.R6Tci,~~~~~:~~~~ CORPORATION"

QTY

I
2

R5B RS6, RS9

RES. 2K 1/4W 5'

1302388

R6 ,R13 ,R20,R27 ,R34, R41,
R48

RES 2.7K,~W,511

1300426

X·Y COORDINATE HOLE LOCATION

K- CO ·5410B05-0-.

ASSY/DRILLING HOLE LAYOUT

f - AH- 541 OB05-0- 5

REF

MODULE ECO HI STORY

B-MH· 5410B05- 0-6

ETCHEO C1RCU I T BOARD

5010806

CI6,C17 ,C18

CAP 25UF 25Y 10'/. />"L ~L

1000075

5
6

REF DES I GNAT I ON

DESCRIPTION

PART NO,

R94,R99,RI16 ,RI17 ,R122

RES 3. 9K,~W ,5%

1300444

R5,R7 ,RI2,RI5,RI9,R21,
R26, R28 , R33, R35, R40 , R42
R47,R49,

RES 4. 7K,~W,5"

1300447

AS7(~'>I, AI?8" RIOq,R 110

RES 10K,~W,5%

1300479

RES 18K ,~w 5%

1302465

RES 560 ~W 5%

53
54

Cl THRU C7

CAP ,OOSU!" 100V ZO·/. DISC

IOOniCS

C13,C15, C2~, eel

CAP .0IUF 100Y 20% OISC

1001610-01

C14

CAP .22UF 100Y 10% MYLAR

1000037

CAP 190UF 12Y 20% AL EL

1009433

C9,Cl0

CAP 20UF 50V 10% AL

1002839

9
10

R8 ,R14,R22, R29, R36, R43,
R50
R120

Tp.,I'I'

1009725

R92, R93,

RES 41D4~W 1%

1301890
li03047

1100114

R98, R102

RES 619,~W 1%

1305126

R59

RES 196 ,~W 1%

1302956

Rll~

RES 121,1/~W 1%

1302.951

9001 ( 13

02~ ,0 I, Olj" 017, 018, 0 19,020,

FA'S'I'OI'l ,"'~
TRANS 2\-\:'1\<0

15030",':!!

1509338

1503068

1509581

Cl1,C12

CAP 1. 5UF 35V 10 %

05,06,011 ,016,021,~6~1,
036,040 THRU 045 p ,
057,064 THRU 070,056

OIOOE 0664

01 THRU 04,07 THRU 010,012
THRU 015,017 THRU 020,022
THRU 025,021 THRU 030,032
THRU 035

o lODE I N4144

037, 046 THRU 051

o lODE I N4004

1105796

059 THRU 062

OIOOE MR7S2

1110.b15

058

BR lOGE

1110714

071,072,038,039,063

1
4

1105648

Z
8

DIODE .4M 5.1Ai/

Jl
J2, J3, J4, J5

S.IV

11, ZENER

1105873

KEYING PLUGS

1211S':lS

CONN 3M 40 PIN

1210073

~'-I

9 Q2,QAr,Q6,QBQIO,OI2 ,Qli.,q38,Q39/ TRANS 6531 B
2
042,043
TRANS 3715
1
051
TRANS 2N3791

C
!

033.034,036 ,
047,048

a26

TRANS MPSA05

1510705

03.0S ,0, ,OS,01\,013,

TRANS MPSA55

1510706

1301695

a.'lS,o..~O,Q.'2,041 ,049

TRANS TIP 31 A

1512.590

RES 0.50 2w 1%
RES 4, 5W W,W.

13JIS67
13\\,,"24

24
25

a.l~,(l31 ,040.024,050

TRANS TIP 3 2. A

I+-

I C LM309K REGULATOR

1512.589
1910460

I---

RES 100,

1300229

HEAT SINK

141\071

FUSE CLIPS

9009513-0\

69
70

WASHERS, FLA" NYLOI'I ""10
EYELET (M",-,-\\l-L<lK)

9006701

9007266

1"2, F:', F4, F5'

9007240
1211237

73 I--SEE NOTE 4.
74

;.0

1301475

30
31

FUSE 30AM P 32 V GLA S S
FUS .. 3/4AMPSI..ClW !lLClW

E.'<E.LET

sOO~OOO

1300271

900iC013-01

0
-

1""

34-

5CRI::W, PPH 4-40 'f,. 1/2.
NUT, KEP, 4.-40

SOOi055'1

SCRE.W, PpH ,,"-32.)(. 15/16

9007838-01

NUT, K\O:.?, G- 32.

90010560

CA8LE,POWER LJO,q,t<1)

C'AI)-70IO'3fd-O-o 82

INS\.lLJI,."IOR5, "103

~OO1072t

1.N5ULI'.'OR
COMPOUNO) 'I-IE.RMAL

9009S'37

90062108

R80. R2, R9, R16, R23, R30 ,R37 ,
R44, R124, RI25
Rl07

RES 18,%W 5%

1302124

R62

RES 100,3-2W 5%

1300228

Rl04,Rl05 •.

RES 100,10W 5%

Rl03,R97

RES 150 .~Yf, 5%

1310597
1300250

R114, R121

RES 1.1 K ~w 5%

AMP (10132,0-1)

8 /~U~~~5, (32:, R3", RES <.(.0,~,5%

015, Oee, 025,027.035,037,
045,Q46,Q52.

R7 5, R77

RES 180 ,y,W 5%

1300260

R74,R78

1'309639
1301972

34
36

I
I

R90

RES 200, '5W,5,%
RES 270,~W 5%

R71

RES 390, 2W, 5%

1301864

Rl0S

5510831

t--

RES 47,y,W,5%

Rlll,RI12,RII5 RI23

RES 270, 2W, \0°1.

1300288

RES 180 ,~W,5%

1301322

R96

RES 300, 2W, 5%

1309855

R95,Rl00,RI2~

RES 390, ~W 5%

\
\210

1300309

Rl0l

RES 470, 2W, 5%

1303062

A/R

Ic..V'C

R70

RES lSl,y,W.5%

1'30.2336

RES;n::> , y,W 5%

1300291

R85. R8e
R65,

RES lK,4W,5%

1300365

43
44

2
2

R63,R64

RES lK,~W

1300364

R66, R67

RES a2.a ,I.W, 5%

1302G58

11B'l~

RE5.1.5K 14W 5'/0
DIODE IN7i1A. 3.6.V lENER
SCReW PPH 4-40 X.YI6

D52054

\
I

, f-'~

I-I
0
I

L[)

~co

<;t
L[)

8f>

1300391
1110672
9006012 -01

87
88
89

3GI1567

LABEL

1000030'-00

CA,P.I(H'D IOOV 2.0% /)ISC
CI9
RiC8,RG9,R7l,R73,R7tD ,R'79 RES, 470 1/4 W 5.,.

13003/("

,
,

90
9f
92
93

q49S'

REVISIONS

CHK

CHANG, NO.

'- I - -

rREV:'"
I

SlzrD~1

TITLE

LA 36

SCALE
DEC FORM NO
ORO 138

CONN H802 18PIN (MODIFIED)

,R46

Rl ,R51 ,R52,R53.R54,R55,R56

9006'1GO

1209340

~24

1312997

RIVET,POP

1209456

R118

,RIO,
,RI7.
,R31,
,R38.

RES GO,IOW,S%

CONN MAT-N'LOCK $OCI<E.\ HOUSING

R3,

R81,R113

ITEM
NO.

PART NO.

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2
7-26

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"THIS DRAWING AND SPECIFICATIONS, HEREIN, ARE THE
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SHALL NOT BE REPRODUCED OR COPIED OR USED IN WHOlE
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REVISIONS
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TITLE

1~~~-------------1------._----------1-----------------~------------------1---------._-------1----------________1-r-______________-1__----------.-----~--______________~S~C~A~LE~~~~:t~~S~HE~E!Tj3~~O~F~5~:=~~~~J:J[=r:J:Jc:r=J[:t:J:J
8

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7-27

"THIS DRAWING AND SPECIFICATIONS, HEREIN, ARE THE
PROPERTY OF DIGITAL EQUIPMENT CORPORATION AND
SHAll. NOT BE REPRODUCED OR COPIED OR USED IN WHOLE
OR IN PART AS THE BASIS FOR THE MANUFACTURE OR SALE

~~~:~~&f~?:'R~~'~~~~~:~~~T CORPORATION"

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REVISIONS

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~~~--~~--~--~~--~~--~T~ITLE----~~
SCALE

3
7-28

"THIS DRAWING AND SPECIFICATIONS, HEREIN, ARE THE
PROPERTY Of DIGITAL EQUIPMENT CORPORATION AND
SHALL NOT BE REPRODUCED OR COf'IEO OR USED IN WHOLE
OR IN PART AS THE BASIS fOR THE MANUFACTURE OR SALE

g"o.:;~~~Cb~~R6~1~~~~~:::;'.CORPORATION"

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MPC7 ARM
MPC8 LFI
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REVISIONS

CHK

CHANGE NO

REV.
TITLE

SCALE

SHEET

7-29

Signal Glossary for M7728
Logic Board
Mnemonic

Defmition

Source

Destination

MPC3 BMBOO

Buffered Memory Bit 0

E4-2

(MPC3) Ell-IS; (MPC4) E3-I, EIO-2,
EI4-IS, E29-IS, E33-23

MPC3 BMBOI

Buffered Memory Bit I

E4-12

(MPC3) Ell-I; (MPC4) E3-IS, ElO-S,
EI4-14, E29-14, E33-23

MPC3BMB02

Buffered Memory Bit 2

E21-4

(MPC3) EII-IO; (MPC4) E3-14,
EIO-8, EI4-13, E29-13, E33-21,
E64-13

MPC3 BMB03

Buffered Memory Bit 3

E2I-2

(MPC3) EII-9; (MPC4) E3-13, EIO-II,
EI4-11, E29-11, E33-20, E6S-12, 13

MPC3 BMB04

Buffered Memory Bit 4

E21-12

(MPC4) E22-23

MPC3 BMBOS

Buffered Memory Bit S

E21-10

(MPC3) E32-2; (MPC4) E3-2,
EIO-3,6,9,I2, E29-9, E22-22

MPC3 BMB06

Buffered Memory Bit 6

E2I-8

(MPC3) E32-I; (MPC4) EI4-9, E22-2I

MPC3 BMB07

Buffered Memory Bit 7

E2-6

(MPC3) E32-2; (MPC4) E22-20

E62-2

(MPC7) E49-4, E49-10

MPC3CLOCKA
MPC4REG OH

ES-3

(MPC4) E29-1; (MPC3) E9-IS;
(MPC7)E84;(MPC9)E24

MPC4REG I H

ES-2

(MPC4) E29-8; (MPC3) E9-I;
(MPC7) E8-S; (MPC9) E2-S

MPC4REG 2H

ES-6

(MPC4) EI4-I6; (MPC3) E9-2;
(MPC7) E8-12; (MPC9) E2-12

MPC4REG 3H

ES-7

(MPC4) EI4-17; (MPC3) E9-9;
(MPC7) E8-13; (MPC9) E2-13

E6-6

(MPC4) E14-6

MPC4ZEROH
MPC4 CSOO L (BNG 1)

Clocked Selector 04

E22-1

(MPC4) EI6-1

MPC4 CS02 L (BNG 4)

Clocked Selector 04

E22-3

(MPC4) E16-2

MPC4 CS03 L (SKP I)

Clocked Selector 04

E22-4

(MPC4) E3S-13; (MPC3) E16-4

MPC4 CS04 L (SKP 2)

Clocked Selector 04

E22-S

(MPC3) EI6-S

MPC4 CSIO L (STR 1)

Clocked Selector 04

E22-9

(MPC4) E3-3

MPC4 CS12 L (DEC 1)

Clocked Selector 04

E22-11

(MPC4) E33-18, 19

7-31

Signal Glossary for M7728 (Cont)
Logic Board
Destination

Mnemonic:

Definition

Source

MPC4CS15 L(JMP2)

Clocked Selector 04

E22"15

(MPC3) E12-l

MPC4 CS16 L (JMP 3)

Clocked Selector 04

E22-16

(MPC3) EI2-2, 13

MPC4 CS17 L (JMP 4)

Clocked Selector 04

E22-17

(MPC3) E12-4

MPC4 CLR INIT L

Clear Initialize

E33"17

(MPC7) E25-13, E43-11;
(MPC8) E34-10

MPC4 CLR C/B L

Clear Carries or Borrows

E33-16

(MPC7) E39-13

MPC4 SET HOLD L

Set Hold

E35-15

(MPC8) E42-4

MPC4 STEP LF L

Step Line Feed

E33-14

(MPC8)E31-3,11;E37-4

MPC4 CLR HDE L

Clear Head Drive Enable

E33-13

(MPC7) E44-13; (MPC8) E37-11

MPC4 SET HDE L

Set Head Drive Enable

E33-11

(MPC8) E37-10

MPC4 LOAD D/A L

Load Digital/Analog

E33-10

(MPC7) E8-9

MPC4 SET BEL L

Set Bell

E33-9

(MPC8) E34-4

MPC4 CLR BEL L

Clear Bell

E33-8

(MPC8) E34-3

MPC4-1 REGL

Decrement Register

E33-7

(MPC4)E54

MPC4 WRITE BUFF L

Write Buffer

E33-5

(MPC6) E30-1 0; (MPC9) E41,3, E36-3

MPC4 WAD CBA L

Load Character Buffer
Address

E33-4

(MPC9) E2-9

MPC4+1 REGL

Increment Register

E33-3

(MPC4) E5-5

MPC4CLRDAL

,Clear Data Available

E33-2

(MPC6) E30-11

MPC4 CLR KBH L

Clear Keyboard Hold

E33-1

(MPC6) E30-4

MPC4SKIPL

Skip'

. E6-11

(MPC3) E26-12

MPC4 CHAR TEST L

Character Test

E65-8

(MPC4) J5-W

MPC5 S.1.

Serial IN

E42-11

(MPC6) ES5-20

MPC5592NS

592NS

E66-14

(MPC3)E39-9

MPC5 1.184 US H

1.184 ps

E66-12

(MPC3) E39-10; (MPC7),E62-13

MPC5 CLKH

Clock

E19-5

(MPC3) E32-5, 10, (MPC7) E49-1

7-32

Signal Glossary for M7728 (Cont)
Logic Board
Mnemonic

Definition

Destination

Source

MPC5 CLKL

Clock

E19-12

(MPC4) E22-19

MPC5 76 US

76/-1s

E68-11

(MPC7) E54-3, E40-3

MPC5 208 H

208

E68-12

(MPC4) E29-7; (MPC6) E59-7;
(MPC8) E42-1O

MPC5 4.8 KHZ

4.8 kHz

E63-11

(MPC6) E59-4

MPC5 1.76 KHZ

1.76 kHz

E67-11

(MPC6) E57-8

E61-8

(MPC5) J5-A

MPC5 OPTION CLK L
MPC6 REQ TO SEND H

Request To Send

R41

(MPC6) J2-JJ

MPC6 UART DATA 1

DART Data 1

E55-12

(MPC9) E41-4

MPC6 UART DATA 2

UART Data 2

E55-11

(MPC9) E41-6

MPC6 DART DATA 3

DART Data 3

E55-10

(MPC9) E41-10

MPC6 UART DATA 4

DART Data 4

E55-9

(MPC9) E41-12

MPC6 DART DATA 5

UARTData 5

E55-8

(MPC9) E36-4

MPC6 UART DATA 6

DART Data 6

E55-7

(MPC9) E36-6

MPC6 UART DATA 7

UART Data 7

E55-6

(MPC9) E36-10

MPC6 UART P, ERR H

UART Parity Error

E55-13

(MPC9) E36-12

MPC6KBHH

Keyboard Hold

E30-6

(MPC4) E14-20

MPC6S.0.

Serial Out

E55-25

(MPC5) E60-12

MPC6 RD8

RD8

E55-5

(MPC9) E36-12

MPC6WUH

Wake Up

E56-4

(MPC4) E5-14; (MPC3) EI1-14, E9-14

MPC6 CLR DA FF L

Clear

E30-8

(MPC8) E34-11

MPC6DAH

Data Available

E42-3

(MPC4) E14-7

J2-P

(MPC5) E60-13

MPC6 BREAK + L
MPC7 COL INC CNT 0

Column Increment Count 0

E43-3

(MPC8) E39-2; (MPC9) E48-21, E53-21

MPC7 COL INC CNT 1

Column Increment Count 1

E43-2

(MPC9) E48-20, E53-20

MPC7 COL INC CNT 2

Column Increment Count 2

E43-6

(MPC9) E48-19, E53-19

7-33

Signal GlosSary for M7728 (Cont)
Logic Board
Mnemonic

Definition

Source

Destination

MPC7 BORROW H

Borrow

E16-11

(MPC4) E29-22

MPC7 CARRYH

Carry

E16-8

(MPC4)E14-23

MPC7 1.184 US L

L184ps

E62-12

(MPC5) E61-9

MPC7 SUM

Sum

C79

JI-B

MPC7 ARM

Arm

JI-E

MPC7 INC H

Increment

E44-9 .

(MPC4) E29-3

MPC8W. U.L

Wake Up

Q9-C

(MPC8) E34-1, 13, E42-5, E37-13,
H-DD, J5-Z; (MPC6) E30-13; E56-3;
(MPC3) E26-1; (MPC7) E8-1

MPC8 READYH

Ready

E34-9

(MPC6) E38-5; (MPC5) E64-4

MPC8 LF2

Line Feed 2

E28-8

JI-P

MPC8 LF1

Line Feed 1

E28-1O

JI-JJ

MPC8 LF HOLD L

Line Feed Hold

Q14-E

JI-D

MPC8HDENL

Head Drive Enable

E39-6

JI-DD

MPC8 BEL

Bell

R58

JI-TT

MPC9 PNTABL H

Printable

E61-6

(MPC4) E14-1

MPC9 BS L

Back Space

E23-9

(MPC4) E29-20

MPC9HTL

Horizontal Tab

E23-7

(MPC4) E29-21

MPC9 LFH

Line Feed

E23-6

(MPC4) E29-5

MPC9CRH

Carriage Return

E23-3

(MPC4) E29-4

MPC9 BELH

Bell

E23-1

(MPC4) E29-6

MPC9ERRORH

Parity Error

E56-10

(MPC7) E39-1

7-34

8
ARE THE

NOTES:

SHAll

EOR IN
URE OR SALE OF

Ins

I. CONNECTORS:
J 1 _ _ JI POWER BOARD
J2 _ _ KE't'&OARD
J3 ___ Z0MA. SERIAL LINE
OPTIONAL 1.NTERfACE PORT
J 4- _

EQUIPMENT CORPORATION"

91
92

COMPONENTS 'WITHIN OUTLINE NOT
INSERTtD IN PREFERRED CONFIGURATION

REF DES NOT USED ARE:
CIOO,C"I,C'2.C"4. C48-C~8
MAXIMUM REF DES USED ARE:

SEE NOTE 2 ,

J5 - - - J5 EXPANDER OPTION MOUNTING BOARD

TP266

u n.
>=

""20, RI2~, U, ... C'l7. 0\4, J5. CR 1,0.15

I-

SPARES

I.I~~

E58 SPARE Ie POSITION
E58-8 = GND
E58-1" = +SV

10.12

@Di

@iJ

--.

-=---t.J==

CB6

~
~

i
i

----"I~

P -1L_CB_7

(ID

-1L_CB_4---"1~ p

tID@

_;.®i

+SV

:J; ~(CI-e~I'Jl

+~(C83-C88
+

e~3 -t4 7

~~~r I I'I~~0 I

RI18
IK

RII'l
IK

RI2Ql
IK

T?x7; TP~

Tg:z-

TP~

+10

RI21
IK

R12~

<;t
r<)

>
n.

I-

u
TPXI

8640
LM30lA
1702A
74123
74150
74154
74161
74175
74190
74193
7442
7439
7493
MK2600P

I
-

8
12
12

8
8

8
8
8
8
10
12

16
24
24
16
16
16
16
16
16
5
24

UART

Ie TYPE

GNO

+5V

I-

FIRST USED ON OPTION MODEL

LA~b

ETCH BOARD REV.

IB I

PARTS LIST

GNO AND 5V ARE USUALLY PIN 7 AND 14
RESPECTIVELY EXCEPTIONS ARE STATED ABOVE

Ie PIN LOCATIONS
D~C

'OIilM "0.

OItO Ill .•

SEMICONDUCTOR CONVERSION CHART
SHEET
I
OF
9
OIST. 1 1 1 1 1 1 1 1 1-.l
~1~~~3~~~~1~~~2~~~~1~~~1~~~

7-35

II ·R. I 1-~-.~~{LV'4 -S~ 21

"THIS DRAWING AND SPECIFICATIONS. HEREIN, ME THE
PROPERTY OF DIGITAL EQUIPMENT CORPORATION AND
SHALL NOT IE REPRODUCED OR COPIED OR USED IN WHOLE
OR IN PART AS THE BASIS FOR THE MANUFACTURE OR $J\L£

~~~~~~ ~~~T~~~:=r CORPORATION"
CU)'/VAR

0
w

I-

55
LL

REVISIONS
CHANGE NO.

I REV.
I

1
PIC FOIIM ItO.
0110 ua

(()

ITEM
NO.

DESCRIPTION

PART

NO.

REF

ASSY!URILLING HOlE LAYOOT

I-AlI-I0728·9·5

R15

RES. 121K %11 1% Mf

1305255

REF

IIDJLE ECO HI STORY

8·It!-M772Q·9·6

R9,Rl0

RES 232K %11 1% ~F

U05424

ETCIED Clfl:tJlT IIlARII

5011682

R21 ,R25

RES 1M %W 5% CC

1309595

54
55

REI'. DESIGNATION

NO.

'"=>
V1

REF. DES\GNATION

PAR,.

DESCRIPTION

NO.

C71,C76,C8D,C97

CAP39 PF l00V 5% OIPPBl MICA

1000010

R17

RES 30.1K %W 10/, MF

1311594

C91

CAP 47DPF l00V 5% OJPPBl MICA

1000024

R20

RES 2. 15K %W 1% MF

1311653

C82

CAP .22UF l00V 10% MYLAR

1000037

TRANS I STOR 045C8

1510596

C72 C75,C79

CAP .047UF lOOV 10% MYLAR

1000051

02'06,010·014

TRANS I STOR MPSA05

1510705

C67 C73

CAP 25UF 25V AL EL

l00D075

07,08,015

TRANS I STOR MPSA55

1510706

59
60

cn C81 C9D

IEt?Ii'fts3 ,C68 ,C74, C78, C89,C92-C9I CAP .0lUF 100V OISC

1001610·01

TRANS I STOR OEC6 531 B

1509338

C65,C66, C9i>

CAP .D05UF 100V 0I SC

1001765

CRI

CRYSTAL 1.6896 MHZ(WIRE LEADS)

1811689

C83·C88

CAP 500F 25V AL EL

1001796

E25,E26,E30,E31,E34,E37,E40
E44, E45, E50, E54

I .C. 7474

1905547

DIODE 0681

1100113

05,07,08,012,014

DIODE 0684

1100114

E32, E38. E39, E49, E60, E65

I . C. 7400

1905575

09,010

DIODE IN748A3,9iI 5% ZENER

1100122

El0,E47,E52,EB7

I .C. 7401

1905590

DIODE IN746A 3.3V 5% ZENER

1104860

E66, E68

I....C. 7493A

1909854

011

DIODE MC1130t

1105810

E4,E21,E28,E35,E56,E62

I, C. 7404

1909686

oI ODE 1N4004

1105796

E22, E33

I.C. 74154

1909701

.--.. -~

013

010DE4M5JAZI 5. IV 1% ZENER

1105873

E18

I. C. 7413

J3,J4

CONN 8 PIN MATE·N·lOCK(HOOSING)

1209340-00

E5.E9,Ell

I. C. 74193

JI,J2,J5

CONN 40 PIN

BERG

1209941-02

E23

SOCKET, MATE·N·lDCK 61320·3

12011456·01

12JOS93

KEYING PWG MATE-N'lDCK

1211595

RSO

RES 47 %W 5% CC

1300202

R7,R33,R58,R91.R'4"

E48,E53

- -t - - . - - - - - - . - . - - SOCKET, IC,24 Pftol

RES 100 %W 5% CC

1300229

R47

RES 150, %W 5% CC

1300250

E61

_~C.• !442
I.C. 7437

E43

EI4,E29

1909989

~!~~~~--. .. - -

I.C. 74190

1910095

I.C. 74150

1910153

~L
74
75

E6, E12, E16, E42 ,E64

I.C. 7408

i 1910155

E13,E17,E27

I, C, LM30lAN DIP

1910282

l+-

E3,E36,E41

I . C. 7489

'1910396

I--

E19

I.C. 74123

1910436

E55

I ,C, UART

1910459

~lJ
I--

Re6,III9

RES 180 ~ 5% CC

1300260

E63,E67

I .C. 74161

1910650

R49,R89

RES 220 %W 5% CC

1300271

E2, E8

I .C. 74175

1910651

RaO.

RES 330 %W 5% CC

1300295

E46,E51

I .C. 8093

1910837

R29, R34, R88

RES 470 %W 5'.1 CC

1300316

E59

I. C. 8640

19!J~ ___.

El, E7

I. C. SOC75, 4N26

1300365

RES lK %W 5'.1 CC

1117 ,JfJ8 ,R70 ,R71

RES IK lW 5% CC

1300368

PROM, 1702A, PROGRAMMED

1911998
-------1----- .
PROMS
23082A4

PROM, 1702A, PROGRAMMED PROM I

- ..

Ral

RES 1.5K %W 5% Ill;

1300391

E53

ROM,MK2627(ALPHA SET,ASCII )

23070A6

R37 .~,R53, R93, R96, R1D2,Rl09,
Rll0,Rll1,R113'RI17, ~IOO

RES IDK %W 5'.1 CC

1300479

E48

ROM,MK2626(NO.SET, ASCII)

23071A6

R16

RES 59.0K %W 1% \ooPPM MF INi5lH

1300525

E15

ROM, MK2628( CONTROL PROGRAM)

23082A6

R97,~.

RES 10 %W 5% CC

1301317

SCREW, SLOTTED BI NO HO 4.40 ,5/1 9006010·4

RI3,R22,R2B

RES 180 %W 5% CC

1301322

NUT, KEP 4·40

WASHER, FLAT. NYlON #6

EYELET(MATE-N-LOCK MOUNTING)

9006732

FASTON TERMINAL

9007113

AIR

THERMAL COMPOUND

9008268

EYELET (FASTEN MOUNTING)

9009000

R4B

RES 68K %W 5% CC

1301327

RlI,R92

lIES 820 %W 5% CC

1301775

R36,R54,R56 ,R57 ,R59,R60

RES 5.6K %W 5% CC

1301874

, ,
8

R72'R75, R79·R81·R95

lIES 47K %W 5% CC

1302177

R82.R87,:'· ..

RES 2K %W 5% CC

1302388

R51

lIES 47DK %W 5% IX:

1302398

R27,R23

lIES 511 %W r,4 llX1'1'11 MF lNi5 O·F

lIES lOOK %W 5% CC

1302468

R18

RES 14.7K %W 1% lOO1'1'M MF IHi5 O·F

1302941

R12,R14

RES 1. DOlI %W 1% lOO1'1'M MF IHi5 O-F

1303114

R24,R2B

lIES 5 .11K %W 1% 1011'I'III MF IHi5 O·F

13D4854

RI9

RES 3.48K %W 1% lOO1'1'M MF IHi5 D-F

1305114

Wl'W5,W18,W20

WIRE, INSULATED JUMPER

c9S

CAP .J uf' IOOV COlo

Riol

C94

RES 2.70 '/4W 5 % cc
CAP 39vF' 10V 10% So TAt«

-- ~

9003185

DISC 1000030

S~E~s1

2
7-36

OIST. I

I--

1301~n.

100007",

:~o

101

I SHEET 2

-~!!!. -

loa

+--+-

9009157

CE"WJT PE.R.MA SOIJ.!>"1 0 a

LA36 MPC

- - - .. - - - - ---

AIR

~N
zl'I'-

-- -85

WIRE, INsul.ArED JUMPER, 30llll/G 9105740

SCALE

"~CXlI

--.- 8.3~

Alro. Alp..

TITLE

-- 82

9QIl6_557 ---"- - .-.- 9..1..._
!!.L
----- ~~~OL ___

1302411

?sl

86
-- 1---87
.-88
------ -89

2(,

23083A4

-I

- - - ~O_

-.~----

2.~

Rl·R4, R32, R35, R45 ,R52, R55, 1111·1115
R76,R94,R99,R1l2,RI18- RI23, R+4

~1_
72

-----,-

I--

1910018
._----+--------.

CHK I

;::

i\::

'"
t±'

ITEM

W
f-.
:::J
I-

REF

25 2:"1

LU
Q:

w
a.

53 54

G.Tf I'IAfi.

NUMBER

REV.

M7728-0-1

I I

I I II

5
+& 0---,.
4

~r::n.~r=AL'=::;.CORPOAATION"

TPXS'-'

M1'C4 CSI" L

l"!l

7408
3
EI2 f'J

MPC4 C515 L

+0/3

12.

TPX," 1

EI2.

"....i:L

r -

~O I t &
7i~t

I"IPC51.184 US H

'~4!l)4

'1
10

74rtJrtJ
E3'1

8
TPY2

P
0P

13
tC

MPC3 CLOCK A

3 FARS h 5
C 0~

1(11'1>
TI'XII

9,"

MPC4 C511 L

R5"
S.GK

~ 15 I'!>

iP"6.,

_~ i<'--'1'1-12~r-;rEll}
13

TPZ .... ~

MPC:, ~M~(Zl1

1.... 00

-r!- 03 1~:~~
I

MPC:'J BM!>/lll

9TPX40
R2.(J) 1------,-+-+-+-+-+--------+-+---'-----------'

9TPX.... 4

PROGRAM

•

134~7~~----_r~_r~~---------------- MPO 1'11303
B3~b~--~~~~~~----------- MI'C ~ 1'11302
132~5~~_._+_+~_r~~----------------- MPC:' l'IB0 I
vee

131 ~4-~r_~~~~~~----------- MI'C"" 1'11300

f----o TPl( 4 (.,

~~b
~
TPl47

--o-IZV

pil01UF
:!::

C~
2SUF

-~ 01 AOORESS RI(I)~2~_,_t++_H_+--------+_I__..J......---------------'

MPC~ BMB0~ -~ 00

C ROM
OnTT

ebB

~~
lr

TP""!l~

R0(O 1--...,..-.1-++-+-+-++-------+-+---'----------------'

ern cup LD CON
'--_ _M_PC_b_W_U_H________1......
4'(5

--~----

".~_4
+1::1

-- - -- - - - - -- - -------- - --- -- -----

----- -

---I- -- -- - - - - -

9~5V
11

~ Ae.

€2.4

2(1) A4
ZI
(1):317

I TP )(51

[//
TPX4B

20 1\4
. 001 1(21
21
<W0:177
9

3
12

~ "BB

.!.!. vce

Oil4 7

'------------..,-t A0

003

002~
001 ~

23
+5V"

I
I

~ I"

0(lJ4 "1

AI
A0

~ v~
~ 02
23

~~n VGG CS

+SY

01
VOO VGG

~ 16

I....

"'P- 5.IV
02
Q

D:>

T~:3 ~12

1'<78

--f'S.IV

MPC3 Me,(2I3

003t-:e.:---++-+-++o------- MPC'!> MB\2I2.
002
MI'C'!> MB0 I

00\ 4

c~\,

.11J11~

MPC3 Mll(ll(ll

C70

JJ2T~

C5
14

I
I
I

TPX41 ~

SU~STITUTE

TP ;!41
MPC3 131'11303

7Pf~

TP '1'I('
IIIPC3

-'iTPYIS
MPC3 BI'IBQJ I

BMP,0~

ITPlS7

B
MPC:, MB~\Il

MPC3 BM1304

TPr: ~4 I
V

-4

MPO MB(2Ib

:~ P~M I ~::I-a--++-,r----------:;~~ :!:~

r--- 'ICC

2:2 02

D\IlBr,I,-:I:--T"------------ MPC ~ M"B01

19 AS

007 10
9

3 "

E20

"'Pc':' 131'11305

Q 01
-'f OfOb2

DJ1lE! II

L----------I-1~~ ffiOM0 :~ 8

~12

113

1(2)0

l!!.. A7 iTIIl2A
PGM

1102A

A7
IB A'"
,--_ _ _.,.19..,-t A5

l:IPC"2, 'eoMB01O

ITPYll

RfO

9i~V

PGM

I TP )(:!>7

~10
~
TI')(41

I
I
I
I

MPC~ BMB(Z!I

III

G.I
O'tSCB

I
I

ITPX2h

TP)(51l1

1---

MKZG.ZfO
E 15

L _______ ~

REG
0'~

MBIIl (,
MPC3MBQ}S
MPC3 MBQ}4

'------T':"I---....

R-:,(I) i-7'--_--,.++-I+________-+-+_LT_P_X_4_2___-'

10
MPn BMB/llZ - ' - - 02

MPC 3

135 B

~ AI

CR'f BR'tI

MPC:'J BM13(Z>3

5Q1NS(Zl~

~ 1'104 r-:"=----------=.-{ B2

ZQ}

~2nB

I
~C
2 7 .... 00 Yr3r-_______________
4..,-t
E32
5 7'1-00
MPCS ClK H
E32
10

MPC3 BMB0G

LO CUPClR CON

I..'

1r-------;--,-'-I

'0(,

~X>-G;,....J......I---L---Y------\II..JyIS 1414
~
Lo +13

137 IQ} I

I .--.;....:,23=-1 C;:)5 I

--,

BE> 1-:1-:::1-'-1_ _ _ _ _ _~---------MPC3 MB07

___R'II'T\I\o--r-_----''---''-Z2:::..tC'''0

-u:-

( +5V

12 D i r e
1'1-7 ....
E2f, 'J
7'1-0/3 xrf,=---__I..,-tl C
8
EI6

MPC4 SKIP L

MPC4 CS!l)3 L 4
S
l'IPC4 C504 L

PREFERRED CONFI(l,UR~TION

13 A'

MPCS 5'J?NS

H1I8WnN

12nl!l
L-_-+
T'_I_ _+-l
2 CSZ
CRY !R'N
I
3
, ..1.....
T
I'IPCf> WU L - '
OTPl.e.4
C53
T oJ;.>
T
14 A8
1ilPC4 REG 3 H -r-- 03 E~
R"!>(\) I - - - - - - - , . - - - - - - - + - + - - ' - - - - - = - - - - - - - : - - - : : - i
nTPle."r--------_ _:,-:-15=-j ~ T
MPC4 REG Z H -~ 02
R2 (I) ..."______--.+_-------+-+---1I __.....J
'" A"
TPX e.3
I
PROGRAM
2
IT
MPC+ REG I H -r-- 01 A!:f:a<?S RI{\)
8 ~A:
15
4 1
'3
OTPX4~
..
MPC'I REG 0 H -I-'-"- 00
:
R0 (J) I--___--,.-+-+-+__________-+-+-_...I-T____-'
19 A 3

Z
I

1-0-8GLL~

"THIS DRAWING AND SPEClFlCATtoNS. HIRIIN, AR£
PROPERTY OF DIGITAL EQUIPMENT COIU'OItATtcIN AND
SHALL Hen' H IUPRCX)UCB) OR COPIED OR USID IN WHDLI
OR. IN PART AS THE WIS FOR THE IMN\.fACTURE OR. SALE

I
I

I
i

C.ONFIGUl<ATION

L __________ ~ ____________________________________________ - ______ -- -- _______ ~
REVISIONS

CHK

CHANGE NO.

REV.

TITLE

REV.

LA36 MPC

1~~~~~_~------~--~--~--r-~------~----------------~----------------~~-------r------~~------________~~~--------------L-------~---L-----------__-CS~~~L~E_r~--~-~~~~L-~~~--~~~~~~-L-L~--~~~
... ,"

7-37

PROPERTY OF DIGITAL EQUIPMENT CORPORATION AND
SHALL NOT IE RlEPRODUCm OR COPIED OR USED IN WHOLE
OR IN PART AS TH( IASIS FOR THE MANUfACTURE OR SALE

------I
"'':>4

~+SY

5.101<

t5V

II
TPX"

8(;4(7)

E~'}

rt'3
EGG

TPX3

461T
RIPPLE
R,,{\)

CLR

RlzK!)

TP;!.t;;!Z)

MPCI

RC,7
IK
1'.1

-lJrr-

MPCS 1·184 US H

'W7

r---JV~---n

t5V

~;--- !"IPCS

RIo8
IK,IW

20MA
LOOP

TPY2G

RS2
IK

2.
RSIil

\,J2

CLI<II' CLKI
14

R4')
22(3

3.?:N

OPTION eLK L

TPVII

-t

RECEI'IE

R I (P

1'\20)

I \,JJ

04
741.A

Rb5

CR I
I. 1.8!J I. (2) 0
I1H'e

TPX8

RS5
It(

7404
E.,2

lI)8WnN

RIOlO
180

cF
3 pr

RSb
5.bK

.005UF

r~=~l>in5~~~~~=:~M~Ni- CORPORATION"

tO~

1-0-82LLIAl

CiOS

"THIS DRAWING AND SPECI'FICATIQNS, HEREIN, ARE TH£

ClA

ZOV

R53
10K

MPSA0S

~+SV

elK H

y_
IYJ3

t).!.=-~- MPC5 CLK L

Tl'X51

~~2

18(2)

c
TRANSM Ii

It,)3

TPX9

EG8

R0(1)
R I (I)

02.

RZ(I)

R3(1)

J2.-lJ JZ-F

12
II

MPCS /j-·5I<H'l

CLR

MI'CS IGUS

R I(n
12

1'<0(1)
CLR

E(,')

MPCS 208 H

C.r/>.

1PX I

g
R2(1)

R70
I K,\'W

'WG

BINAR'I'
LD COUNTER
+11
ClK

1'<7 I
I K,\'W

II 1404
H2

TP;!. 7

7404

p.."-L-_ ~lPC5 ",:1.

iP;!'b
REO. TO SEND H

B
3
4

DI4

R(2lCl)

R I (I)

R2(11

R3(1)

TTL XMT DATA (s.O~
L: MARK

1413
12
II

141hl
CLR
E('7
LD
BINARY
CLK COUNTER
+15
CNTEN

TPVI4

c~.

CHANGE NO.

I·IUF

-=
TP"l12

-:::

10104

LOCAL

+SV
MPCS \.Ib KHt

R~4

MPC(; S.D.
!lST

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S 1'T0'T

+5V

tl2V

t5V

5.(;K
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MPCI

CHK

W.I..\.

c95

YJIZ

----

1rJ2

\,J3

\,J4

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'W8

\,J"J

FULL DJPLEl< ACTIV E

l2l

FlJLL DUPLE.X PASSIVE

(21

(2)

11';:8

TPZ 1'1-

CONFIGURATIONS SEE LA3" SERVICE MANUAL

JUMPER

LEGEND:

LOCAL

TPll

Eb2

REVISIONS

LINE
YJ/LOLIIL rK,NT

L: MRRK
~IPC('

ON LINE

TTL !lEC OAiA (S.l.)

tC
MPCI

NOTE: FOR OTHER

R48
G13K

-~-20V
J4

14101
II.

FlJNCTION
ON

----

4 1',11
RIPPLE
R3(1)

:5
2

00
DI

MPCB READY H

10113 'W14
TTL DATA TERMINAL REAm H

I ~ JlJMPER INSERTED
(Zl ~ JUMPER NOT INSERTED

REV.
TITLE

LA36 MPC

SCALE
OIC FORM NO.

0110 ue

3
7-39

"THIS DRAWING AND SPECIFICATIONS. HEREIN, ARE THE
PROPERTY OF DIGITAL EQUIPMENT COIU'OAAT1ON AND
~ NOT IE REPRObUCED OR COPIED OR USED IN WHOLf
OR IN PA RT AS THE BASIS fOR THE MANUfACTURE OR SALE
OF IT£MS
COPYRIGHT
CORPORATION"

W~~~~TJI~~~W:~

FUNCTION

-!J- J f -.

150 BAUD

(2)

300 BAUD

liD BIIUD

FUNC.TlON
8TH BI1 MARK I N G

8TH BI1 Sf'ACEING
EVEN PARITY
ODD 'PARITY

)(

et!

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et!

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(2)

J5
R43
10K
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MPC4 WRITE BUFF L

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8

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MPCIo elR DA H

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FUNCTION GNO
C

TF'~21

TPV25
WI5

I<
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TPI2i21

KE1 '3
KEY 2
KEy I

r-MPCb REG. TO SEND H

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2
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7

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17'1-01

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rmv
13

R3':l
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C
v

S
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n
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40
XRDY
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38 35 3b
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TPX4

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MPC4 ClR k'B H

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8
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4

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32
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31
XOG
30
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28
X03
E:7

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MPC8 REAm H

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OR 'ERR ~

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O?TION DA L

CLEAR DA L

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TT

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100

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13 E3B

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LEGEND: (2) > JUM?ER lN5ERTED
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MPCb llART OIlTA I

E28

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.... 4

'E51
TPV7

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B 1401
9

ES7
'----'

- - 0 TP'"

let!

REVISIONS
CHK

CHANGE NO.

REV.
TITLE

LA36 MPC

SCALE
OIC~"

ORO 131

MO.

~C\

3
740

NUMBER

REV.

'* '*"*

PRIN'T MOT 10J'l
RE.TURN 1'101'101'1

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(.010')

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L- 'AI:,]

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2 "'_ 7
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301"

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4

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2

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I A>;:,s---L..-""V\fIr--.--l---.I--..!;2'C.t-..J11413
I

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9

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C93
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MPC3 eLK A --

(

TPY26 C

7400
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4

RIB
1'I--1K
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3 H.....!2 03

R3Cil 15

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REG INFORMATION LOADED IN TO D/A
D/A C+'PRINI-: RETURN MOTION)
R£G3REG2REGIREGO
NOMINAL
(I) (I) (I) (I) SPEED (IPS)

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HII
B211J

elK

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(/J

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(Zl
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I
I
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121
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I

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B

~.
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~--------~~~ARM

MPC8 W.U. L

H!33
2.K

H!32
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05
m.b4

WXZS0-~....l---------------------------------------------------

REVISIONS

I REV.

TPXI!2l

TITLE

(SHEET

SCALE

NUMBER

SDIZEr:o~S~'

LA36 MPC
(MPC7)

•......

-11.4
- 19· 0
- 22. a

I
I

~!~----~---+<rI--MPC7SUM

10000K

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C/32 _
C19
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CHANGE NO.

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~ D I h"
~ 1414 f-'

I
+E

t--_ _ _ _-=3'--\+ I 8
i~
-=
301 . G
.
____-+______-.____________~--~----~2~E27
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r

I ".

MPC4 CLR HOE L

-12Y~S~

RII2l
232K
1%

1\ II CH4(21~

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I ;S-MPCl INC H

1'1-14

\;/1

MPC'l- REG 2 H ~ 02

CHK

12 D

E4':l

MPC't CLR INI'T L--:::J

1/2l~ITPX22

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14115

TPY2<j (

I'II\)I/MIN~

0---'-1-+-

2c-~~--~
~41~1:>£E54

L------------~C!1l~
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T?Y30

L-oTPY"

91: E

~ ~

'------=- D
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1'1-1'T~
TPY~2.

R CLK

H_+-1_3ah4~~1~2:...·
--t=+=====:::;=++=====~~=l~~7IE4!~(2)0
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13 E32
12

1400
E49

t'lPC1 CARR,( H

+13

liZ!

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COUNTER
INC

CB'J

..., ...... OI/2l
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3·9Y

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8
EI"

r-:-- C I~

TPXI4

1.(211 uF

::-

c..:!:... ENB

f----i--aCLK

I J-h""B---I--r~
741'1'1"'

1414'"

P" ~

f-----oTPX 11

'l-

R2"

R'3T

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eLK H

MPCS

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SIN.=--

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E'I3

l---t==t==t=======i=====:::::-tl==1r-H~"":5~ LO COLUMN

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R<jB
10

_______ 0-11' M~:5~E~

741::JO

\I
Lr

+E
+I2V

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14H I"'
E2~ 5
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0-4..::15".,00
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1-------

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'*'

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r-!-- 0 I

C32

O'J
IN1'tBA
Y
3·3V -:!:.

__________________

R 2(\) I-b:;;...-_ _ MPC1 COLINe CNT 2
2
R 1(1)
1 - - - - MPCl COL INC eNl I
R (1)0) I-~=---- MPCl coL INC eNT 0

[L[]
I 13 ~
r---o

R~O)rT~

~,..!. 03
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::-11.

1~0~ b I
+

TP'!.IB Q

OF--g-

~~I

M7728-0-1
( (
DIST. I I I I I I

I
741

REV.

c
I

8
"THIS DAAWING ~ SNCIFJCATJONS. HPtlIN. ARE T...:
HU:IPIRTY OP DfGITAL EQUIPMENT ~11ON ~
SMAU,. HOT • IIlIPROOUCI!D OR COPIID OR U5ID IN WHOLI
OR IN PART AS THE WIS FOR THE IMNI.,JFACTURE OR SALE

LF2 LFI

~'W~~=~~CORPORATION"

HOLD
STP LF
.£TP LF

(iii

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STP LF

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8

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13
MPC'I STEP LF L
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5·IV

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D"b4

MPC'f SET HOLD L

MPC'J PARITX ERROR H

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R32.
IK

0.15
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MPC.2 COL INC COUNT ill
MPC'l- seT HOE L

'.J.U. L

2SUI'

MPC8 IF HOLD L

0.7
MPSAS5

MPC8 HD EN L

MPC'l- ClR \.IDE L

R:,!2\
330

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100

TT
MPC8 BEl

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MPC'l- SET BEL L

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410

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PAPER OUT 5W ITCH

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TPl2~

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::TP12'1

TPl~

TPB?

TPH

TPB'l-

TPlS

TPBS

TPl2'

A
REVISIONS

CHK

CHANGE "'0.

REV.

TITLE

MPC8 w.u. L

R58

RB8

1.5K

Q.i3
MPSA55

MPC8 \oJ.U. L

R:'b
5.61<

R:,4
41121

......-...

SCALE

3
742

8
Thi' dr,winl Ind lJIKiflc.tion.. Mr.in, ..... ''''' .......:
• rty of Oltlt,1 IclUiprlMlnt CorpotMion Ind sh,n l'Iot be
reptVC!uc.cl or copied or uMd in whot, or In paort "
tN Nsis for tM m.nufactu... or Nile of item. without
wriINn permillion.

COPYI<IGHTt) 1974 DIGI-rIiL
E:QUIPME.NT CORPORRTION

NOTES.·
I. HE/1TAPPLI£"D 10 QI /iN£) G2 DURING
SOLOERING SHALL NOT EXC££02B5° C
FOP. II PEP./OD OF 15 S£CON/)S.
2.FINlSH~D HOLE SIZE Fo.R MOUNTING Q/ AND Q2.
SH/1LL BE: .078 MIN. J .083 MAX.
.3. AI liND P.2 MUST BE OIVENTEO AS SHOWN,
WITH NOTCH TOWARD C£NT£.R Or BO;9/W.

III. p-O-~tQII~~ ~21,~.12 I

REF

X-Y CooRDINIiTE HOLE LOCfIT/ON K-CO-S4/1tJ49+4

I .

REf

/lS5Y/[)~/LL/NG HOLE LAYOUT D-III1--5<111~9~-5

;::

REF

MODULE ECO HISTORY

8-MfH411~9-~-6

«F

ETCHED CIRCUIT BOARD

D·IA·S~/(j"}'}(j.rJ·d. q.

RI; R2

POT{;'NTIOMETER. 10K

13091'50-12.

Q},Q2

PHOTO TRANSISTOR

151190,,-

c
NOTE 3
.750
REF

t
NOlES I fa

------ty

--II--

TRIM TO .03 MAX

.....-

'r-- .920 REF

f--

K>
i-=
I

r - - - - - - - - - - - _ P.T. COLL. 1
+5V _--------.----1------,
. . . - - - - - - . P. T. COL L 2

RI
POT
I(OK

R2
POT
10K

B
QI

Q2
I--

OTY

ITEM
NO.

PART NO.

DESCRIPTION

REF DESIGNATION

PARTS LIST
ETCH BOARD REV

IB I

1 T 1

EN9Jt'
DATE
TITLE
LA36
~----~----~--__~----~I~~~.~~~·~~~~!-~·~'Y ENCODER PC
.ft

BOARD
r-----t-----~----t-----kl~~~P~:~~~~~I~~~~-~ PHOTOTRANSISTOR
~----I-----II----+-----t NEXT HIGHER ASSY

744

3
DO NOT SCALE

~ '*"Wl.... AND Sl"ECIFtcATION5, HEIlEIN, NIl THE
I'tKIPIIfTY OF DIGIT,AL EQUIJoMlNT COttPOItATION AND

DRAWING

NOTE.S:

5tWJ,. NOT IIIItEMlODUCEO Ok COPtED 011: USED IN 'MO..E
Oft NroI ",n AS THE IASIS FOA THE IrMNUFACTUAf 011: 5ALE

~~~~~iJ:'l~:~NT CORfJORATION"

I. ITE..,""S \ SHIPPING CARTON \ TO BE USED

ONLY FOR SEPE:RAT( KEYBOARD
SHIPMENT.

-CONNECTOR
1<. C:-,,- _ ":T Z

.54- REF
.5BO

_________ 2
3."11 R~F

/'038 DIp.. B055
//
2. PLA.C.E 5

/~80

3.900

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4- PLACE~

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REF

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t
I
,IB8 2 "pLACe~

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I

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0.72-$

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A-PS-9905441 1 5

DIE CUT FOLDER
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KEYCAP

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FIRST USED ON OPTION/MODEL

D-CS-5~I073(,,-O-1

DESCRIPTION

PART NO.

QTY.

LKqJ2

DE..\A\L
S\40WN

f::>....

2.
I

NO.

ITEM

IIII

PARTS LIST

DA15

~~D~IM~E~NS=IOjNI=N='NC~H~ESQI==~~~~~;~:~=~~~~~~T~f,~~i~l;d~l~i~lg~li~~t:a~=I~~:'?:N.:~:iM:~:~:~:::~~~"~~ A
UNLESS OTHERWISE SPECIFIED

WITHOUT

I- DECIMALS

KEYCAP AND A.DA?'T£. R

D-PS-'lOO'1HO-U

KE'1SWITCH ARRAY ~ MODULE.

.xxx =tJos
.xx ~02
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I>-=-.¢!.::.::;:......:~~-?Z.I

TITLE

63 KEY

~CO~RNE~RS~~~~0~~KEYBCJ-,~ ASS(
MATERIAL

FINISH

~~~~~L--------------r--------------------------~---------------------------.r-------------------------

NUMBER

/
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SCALE

NONE

REV.

LK¢2-¢-¢

__r-__________________________,-____________________~____~----------~S~H~EE~T--~/~O~F~----~~~~~~~~~~~~~
4

745

8
This dr.winl.nd speciflc.tion$, h..... ", Ire the proPJ
Irb' of Diehl Equipment CorpoJ'ltion Ind s~.1t not be
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'thlb.,i.forthem.nuf.ctureorsale,.if1Wmlwrthout
writtl'n perrniHlon. COP~lG"'T ~ 11f75

NOT£S:

TWO V41V47YONS OF THIS 80IYAD $H.<9J.1. BE ~~N.A8LE:

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LC.7400
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1910091

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/909686

130009-44-00

13018080024

1302%6 -00

2.)'
26

P.liS 2 OHM {/2WS"%.

/30942/-00

R7,R8
E7

I. C, 74-10

/905S76

JUMPER (INSULATEO.4)

9009165

CAP I,OOO,PF 100 V 5 % MIC/i

1/000042-00

Df.A~SOA
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SOPACE

L-________________________________________________~

JoI.o------------------------------------------------ 13.25 F. B. S.

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DESCRIPTION

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PARTS LIST
ETCH BOARD REV

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"THIS DRAWING AND SPECIFICATIONS, HEREIN, ARE THE

PROPERTY OF DIGITAL EQUIPMENT CORPORATION AND·
SHALL NOT BE REPRODUCED OR COPIED OR USED IN WHOLE
OR IN PART AS THE BASIS FOR THE MANUFACTURE OR SALE
OF ITEMS W!l.HOIJIjVRITTEN PERMISSION.
COPYRIGHT ~137!>.... DIGITAL EQUIPMENT CORPQRATION"

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I 14KEYSWITCHARRAY HOD. D-CS'S4/1'35-CD-1

FIRST USED ON OPTION/MODEL

DESCRIPTION

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INCHES
UNLESS OTHERWISE SPECIFIED
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14

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7-48

DIST.

REV•

CHAPTER 8
ILLUSTRATED PARTS BREAKDOWN

8.1 HOW TO USE THE IPB
8.1.1 General
This IPB is compiled following the organization and nomenclature of the engineering drawing structure.
8.1.2 Major Assembly Locator
The Major Assembly Locator (first illustration) is an index that provides a description and a figure reference for all
illustrations used in this chapter.
8.1.3 Indented Parts List
This chapter identifies each assembly being broken down (figure reference callout), and all parts of that assembly.
Further breakdown of an assembly is shown by an asterisk (*) preceding the item callouts in the Description
Column. The number of asterisks preceding an item is used to denote the subordination of that item with respect to
the Major Assembly. A single asterisk preceding an item description indicates that the item is part of the major
assembly being illustrated. Items that are subordinate to single asterisk items, are denoted by two asterisks (**) and
immediately follow the related single asterisk item. Additional asterisks are used, as required, to denote further
subordination. This system of part identification, provides a means for the user to identify the next higher assembly
item and make alternate selections for parts when the required replacement part or assembly is not immediately
available.
8.1.4 Column Callout Description
8.1.4.1 Figure & Item - Indicates the figure number and item number of each part.
8.1.4.2 Description - Lists the name of the part and pertinent specifications (when required). Asterisks preceding
the description denote the subordination of the part to the next higher assembly.
8.1.4.3 DEC Part No. - Lists the DEC part ordering number. A blank in this column indicates a DEC part number
was not assigned at the time of publication.
8.1.4.4 ECO Cut-In - The notation at the top of this column indicates the ECO level of the system (option), at
which the IPB was initially prepared. Subsequent ECO level designations, that modify existing parts or add new parts
to the device, are inserted in the ECO Cut-In column next to the part that is added or modified. A bracket ([)
preceding the item description is used to indicate the parts affected by ECO's.
8.1.4.5 Vendor Code/Part No. - Indicates vendor parts that are not stocked by DEC. Refer to the Field Service
Spares Catalog (vendor part number to DEC part number) for the vendor code cross-reference.

8-1

8.1.4.6 Used On Code - Letters in this column correspond to the variation codes assigned in Figure 1. Parts with
an Alpha notation(s) are used only in those option variations. A blank indicates that the part is used on all option
variations.
8.1.4.7 Ref Fig No. - A cross reference between illustrations. For each Major Assembly, the number in this column
denotes the figure ·ofthe next higher assembly. For all subassemblies, the number in this column denotes the figure
showing additional detailed breakdown.
8.1.5 Symbol Usage
8.1.5.1 Hardware Designators - Alpha designators for screws (S), washers (W), nuts (N), and retaining rings (R) are
inserted after the item number callouts on the illustration when stacked item numbers are used.
8.1.5.2 Attaching Hardware - The @ symbol is inserted before any part that is used as attaching hardware.
Attaching hardware is denoted as those parts that are not an integral part of the referenced assembly.
8.1.5.3 (NFR) Not Field Repairable - The (NFR) symbol is inserted after any assembly that is not to be field
dismantled.
8.1.5.4 Other Symbols - Any other symbols that are required for kits, accessories, etc., will be explained and
appear as part of the item description.

8-2

EK-LA36-IP-003

ILLUSTRATED
PARTS
BREAKDOWN

LA36
DECwriter II

HOW TO USE THE IPB
GENERAL
This IPB is compiled following the organization and nomenclature
of the engineering drawing structure.
MAJOR ASSEMBL Y LOCATOR
The Major Assembly Locator (first illustration) is an index that
provides a description and a figure reference for all illustrations used
in this manual.
INDENTED PARTS LIST
This manual identifies each assembly being broken down (figure
reference callout), and all parts of that assembly. Further
breakdown of an assembly is shown by an asterisk (*) preceding the
item callouts in the Description Column. The number of asterisks
preceding an item is used to denote the subordination of that item
with respect to the Major Assembly. A single asterisk preceding an
item description indicates that the item is part of the major
assembly being illustrated. Items that are subordinate to single
asterisks items, are denoted by two asterisks (**) and immediately
follow the related single asterisk item. Additional asterisks are used,
as required, to denote further subordination. This system of part
identification, provides a means for the user to identify the next
higher assembly item and make alternate selections for parts when
the required replacement part or assembly is not immediately
available.
COLUMN CALLOUT DESCRIPTION
Figure & Item - I ndicates the figure number and item number of
each part.

ECO Cut·ln - The notation at the top of this column indicates the
ECO level of the system (option), at which the IPB was initially
prepared. Subsequent ECO level designations, that modify existing
parts or add new parts to the device, are inserted in the ECO Cut-I n
column next to the part that is added or modified. A bracket ([)
preceding the item description is used to indicate the parts affected
by ECO's.
Vendor Code/Part No. - Indicates vendor parts that are not stocked
by DEC. Refer to the Field Service Spares Catalog (vendor part
number to DEC part number) for the vendor code cross-reference.
Used On Code - Letters in this column correspond to the variation
codes assigned in Figure 1. Parts with an Alpha notation(s) are used
only in those option variations. A blank indicates that the part is
used on all option variations.
Ref Fig No. - A cross reference between illustrations. For each
Major Assembly, the number in this column denotes the figure of
the next higher assembly. For all subassemblies, the number in this
column denotes the figure showing additional detailed breakdown.
SYMBOL USAGE
Hardware Designators - Alpha designators for screws (S), washers
(W), nuts (N), and retaining rings (R) are inserted after the item
number callouts on the illustration when stacked item numbers are
used.
Attaching Hardware - The @ symbol is inserted before any part
that is used as attaching hardware. Attaching hardware is denoted as
those parts that are not an integral part of the referenced assembly.

Description Lists the name of the part and pertinent
specifications (when required). Asterisks preceding the description
denote the subordination of the part to the next higher assembly.

(NFR) Not Field Repairable - The (NFR) symbol is inserted after
any assembly that is not to be field dismantled.

DEC Part No. - Lists the DEC part ordering number. A blank in
this column indicates a DEC part number was not assigned at the
time of publication.

Other Symbols - Any other symbols that are required for kits,
accessories, etc., will be explained and appear as part of the item
description.

REVISION HISTORY
PRINTING
3rd Printing

ECO LEVEL
LA36
70·096994

00001·00184
00000-00000

DATE

PAGES AFFECTED

2-18·76

This 3rd Printing EK·LA36·IP-003
SUPERSEDES 2nd Printing EK·LA36·IP·002

Copyright © 1974, 1975, 1976 by Digital Equipment Corporation
DEC reserves the right, without notice, to make substitutions and
modifications in the specifications of products documented in this
man ual and further reserves the right to withdraw any of these
products from the market without notice.

DEC is not responsible for errors which may appear in the technical
description (including illustrations and photographs) of the products
covered by this manual.
None of the descriptions contained in this manual imply the
granting of any license whatsoever to make, use or sell equipment
constructed in accordance therewith.

Printed in U.S.A.

8-3

D.C. MOTOR and ENCODER ASSEMBLY
Fig. 9
PRINTER MECHANISM ASSEMBLY
Fig. 3
RIBBON CHASSIS ASSEMBLY
Fig. 4
RIBBON DRIVE ASSEMBLY
Fig. 5

KEYBOARD BEZEL ASSEMBLY
Figs. 12, 12A

IDLER GEAR ASSEMBLY
Fig. 7
CARRIAGE ASSEMBLY
Fig. 6
KEYBOARD BEZEL ASSEMBLY (W/Cursor Controll
Figs. 1 13A

TRANSFORMER ASSEMBLY
Figs. 8, 8A
CABLE and HARNESS ASSEMBLY
Figs. 10, 11, 11A, 14

LA36 DECwriter ASSEMBLY
Figs. 1, 1A
CABINET ASSEMBLY (W/Power Supply
Fig. 2

LA36·01

Major Assembly Locator, LA36 DECwriter"

IPB·LA36

'!I11~llt\~U~
\:.I
PAR TS LIST

37
25

11 S

12W
25W

LA36-02

Ecwriter
Figure 1_ LA36D

Assembly
IPB-L A36

8-5
3

FIG
&
ITEM
NO.
1-

DESCRIPTION

ECO
CUT-IN

VENDOR

DEC
PART NO.

LA36
00001

USED ON
CODE

LA36-CA

00165

LA36-CB

00165

LA36-CC

00165

LA36-CD

00165

LA36-DA

00165

LA36-DB

00165

LA36-DC

00165

LA36-DD

00165

CODE

REF
FIG
PART NO. NO.

MODEL LA36 DECwriter II
(deleted)
Code A used on LA36-CA
(20 mA Current Loop, Numeric Pad, 115V)
(deleted)
Code B used on LA36-CB
(20 mA Current Loop, Numeric Pad, 230V)
(deleted)
Code C used on LA36-CC
(20 mA Current Loop, Numeric Pad, 115V,
PDP-1O)
(deleted)
Code 0 used on LA36-CD
(20 mA Current Loop, Numeric Pad, 230V,
PDP-1O)
(deleted)
Code E used on LA36-DA
(20 mA Current Loop, 115V)
(deleted)
Code F used on LA36-DB
(20 mA Current Loop, 230V)
(deleted)
Code G used on LA36-DC
(20 mA Current Loop, 115V, PDP-1O)
(deleted)
Code H used on LA36-DD
(20 mA Current Loop, 230V, PDP-l0)
1

2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

17
18

19
20
21
22
23
24
25

IPB-LA36

*CABINET ASSEMBLY W/POWER SUPPLY
(deleted)
(115V)
*CABINET ASSEMBLY W/POWER SUPPL Y
(deleted)
(230V)

70-09648-01

*Guide, Paper (deleted)
*Guide, Paper (added)
*Screw, Phi Pan Hd No. 8-32 x .38
*Washer, Flat NO.8
*Washer, Lock Split No.8
*PRINTER MECHANISM ASSEMBLY
*Screw, Phi Pan Hd No. 10-32 x .94
*Washer, Lock Split No. 10
*Nut, Well No. 10-32
*PRINT HEAD ASSEMBLY (NFR)
*Screw, Phi Pan Hd No. 6-32 x .56
*Washer, Lock Int Tooth No.6
*Clamp, Cable
*Tape, Double Coated, .50 Wide
*Screw, Phi Pan Hd No. 4-40 x .38
*Washer, Flat NO.4
*Nut, Kep No. 4-40
*KEYBOARD BEZEL ASSEMBL Y
*KEYBOARD BEZEL ASSEMBLY
(With Numeric Pad)
*CABLE ASSEMBLY (LA36 Keyboard)
*Jumper (LA36 Keyboard, Not Shown)
*Cable Tie
*Screw, Phi Pan Hd No. 6-32 x .38
*Washer, Lock Ext Tooth NO.6
*Washer, Lock Split NO.6
*Washer, Flat No.6

74-11430-00
74-12158-00
90-06037-01
90-06660-00
90-06690-00
70-09696-00
90-08955-01
90-07906-00
90-08896-00
70-09883-00
90-07793-01
90-06633-00
12-02704-00
90-07834-00
90-06011 -01
90-06658-00
90-06557-00
70-09750-01
70-09750-02

ACEG

BDFH

00138
70-09648-02
_00138

70-10000-00
70-10001-04
90-07031-00
90-06022-01
90-07649-00
90-07801-00
90-06653-00

8-6

00052

EFGH
ABCD

12
13

A-H

FIG
&
ITEM
NO.

ECO
CUT-IN
DESCRIPTION

DEC
PART NO.

LA36
00001

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.

126
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42

'CABLE ASSEMBLY (BC05F Interface)
'Ribbon Spool (w/Ribbon)
'Ribbon Spool (Empty)
(deleted)
'Clamp, Cable
'Screw, Phi Pan Hd No. 10-32 x .38 (deleted)
(deleted)
'Washer, Flat No. 10
(deleted)
'Nut, Kep No. 10-32
*Connector, P2, Pin Housing, Mate-N-Lok
(Plugs into PB-J5)
*Housing
'Screw, Phi Pan Hd No. 6·18 x .50 (Self Tapping)
'Cover
'Clip, Cover
'Screw, Phi Pan Hd No. 6·18 x .38 (Self Tapping)
'Nameplate (LA36)
(added)
'Washer, Buna
(added)
'Jumper
(added)
'Spacer, Bezel

BC05F-15
36-10558-00
36-10966-00
90-07089-00
90-06071-01
90-06664-00
90-06565-00
12-09340-01
74-11116-00
90-09630·01
74·11122-00
74-11818·00
90·09622·01
36-11826·00
90·09684·00
70-10001·07
74-13675-00

ABEF

00052
00052
00052
00052

00053
00052
00119

Accessories/Options
tPaper (Package of 100 sheets)
tBasket, Paper
tTable Top
tBracket, Table Support
tTable Assembly
tWheel Assembly
tWheel, Caster
tBracket, Wheel

74·12103-00
74·12016·00
34·11736-00
74·11972·00
70·09897-00
70·09751·00
74·11826·00
74·11824·00

8-7

IPB-LA36

momoomo\
PARTS L1ST/

:::;;:::::=::;.....::;::=.-=+::_ _-

~-;::;:o,;~--:--~-- 29

_2
35

4W
5W
13

14
155
16W

17N

t-- 1
33

LA36-02A

Figure 1A. LA36 DECwriter Assemblv

IPB-LA36

8·8
3

FIG
&
ITEM
NO.
1A-

DESCRIPTION

2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

19
20
21
22
23
24

LA36
00165

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.

MODEL LA36 DECwriter II
Code J used on LA36-CE
(Numeric Pad, Paper Out, 60 Hz, 90-132 V)
Code K used on LA36-CF
(Numeric Pad, Paper Out, 60 Hz, 180-264 V)
Code L used on LA36-CH
(Numeric Pad, Paper Out, 50 Hz, 90-132 V)
Code M used on LA36-CJ
(Numeric Pad, Paper Out, 50 Hz, 180-264 V)
Code N used on LA36-DE
(60 Hz, 90-132V)
Code P used on LA36-DF
(60 Hz, 180-264 V)
Code a used on LA36-DH
(50 Hz, 90-132V)
Code R used on LA36-DJ
(50 Hz, 180-264 V)

DEC
PART NO.

ECO
CUT-IN

*CABINET ASSEMBLY W/POWER SUPPLY
(110V, 60 Hz)
*CABINET ASSEMBLY W/POWE R SUPPLY
(220V, 50 Hz)
*CABINET ASSEMBLY W/POWER SUPPLY
(110V, 50 Hz)
*CABINET ASSEMBLY W/POWER SUPPLY
(220V, 60 Hz)
*Guide, Paper
*Screw, Phi Pan Hd No. 8-32 x .38
*Washer, Flat No.8
*Washer, Split Lock No.8
*PRINTER MECHANISM ASSEMBLY
*Screw, Phi Pan Hd No.1 0-32 x .94
*Washer, Split Lock No.1 0
*Nut, Well No. 10
*PRINT HEAD ASSEMBLY (NFR)
*Screw, Phi Pan Hd No. 6-32 x .56
*Washer, Int Tooth Lock NO.6
*Clamp, Cable
*Tape, Double Coated, .50 wide
*Screw, Phi Pan Hd No. 4-40 x .38
*Washer, Flat No.4
*Nut, Keps No. 4-40
*KEYBOARD BEZEL ASSEMBLY
*KEYBOARD BEZEL ASSEMBLY
W/CURSOR CONTROL
*KEYBOARD CABLE ASSEMBLY (LA36)
*Jumper
*Cable Tie
*Connector, P2, Pin Housing, 8 Pin Mate-N-Lok
(Not Shown)
*Cable Tie Mount (Not Shown)
*Housing

LA36-CE

LA36-CF

LA36-CH

LA36-CJ

LA36-DE

LA36-DF

LA36-DH

LA36-DJ

70-09648-01

70-09648-02

70-09648-03

70-09648-04

74-12158-00
90-06037-01
90-06660-00
90-06690-00
70-09696-00
90-08955-01
90-07906-00
90-08896-00
70-09883-00
90-07793-01
90-06633-00
12-02704-00
90-07834-00
90-06011-01
90-06658-00
90-06557-00
70-09750-01
70-09750-02
70-11519-00
70-10001-11
90-07031-00
12-09340-01

NPaR
JKLM

12A
13A
11A

90-07867-00
74-11116-00

8-9

IPB-LA36

FIG
&
ITEM
NO.

ECO
CUT·IN
DESCRIPTION

DEC
PART NO.

"Screw, Phi Pan Hd No. 6·18 x .50 (Self Tapping)
"Cover
"Clip, Cover
"Screw, Phi Pan Hd No. 6·18 x .38 (Self Tapping)
"Washer, Flat No.6
"Nameplate, LA36
*Washer, Buna (deleted)
"Jumper
*Jumper
"Decal, CAUTION/WARNING
*Spacer, Bezel
"Tubing, Heat Shrinkable
"Cable Tie, Screw Down
*Clip, Harness
*Fuse Holder
"Washer, External Tooth Lock No.8
*Nut, Keps No. 8·32
"Decal, Ground Symbols

90-09630·01
74·11122·00
74·11818·00
90-09622-01
90-06653-00
36·11826·00
90·09684·00
70·10001·07
70·10001-06
36·12483-00
74·13675-00
90-07253·09
90-07033-00
90-08340·00
.12·11638-00
90·08072-00
90·06563-00
36·12680·00

LA36
00165

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.

1A25
26
27
28
29

30
31
32

33
34
35
36
37

38
39
40
41
42

00172

ACCESSORIES
tPaper, Package of 100 Sheets
tRibbon Spool, w/Ribbon
tRibbon Spool, Empty

74·12103-00
36·10966-00
36·10558·00

8-10

IPB-LA36

LA36-03A

Figure 2 . Cabmet
.
Assembly (W/Po werSupply)

8-11

IPB-LA36

FIG
&
ITEM
NO.
2-

DEC
PART NO_

DESCRIPTION
CABINET ASSEMBLY W/POWE R SUPPLY
(deleted)
115V
CABINET ASSEMBLY W/POWER SUPPLY
_ 110V, 60 Hz (added)
CABINET ASSEMBLY W/POWER SUPPLY
(deleted)
230V
CABINET ASSEMBLY W/POWER SUPPLY
_ 220V, 50 Hz (added)
CABINET ASSEMBLY W/POWE R SUPPLY
110V, 50 Hz (added)
CABINET ASSEMBLY W/POWER SUPPLY
_ 220V, 60 Hz (added)

1
2
3
4
5

7
8
9

10
11
12
13
14
15
16

17
18
19
20
21
22
23
24
25
26
27
28

IPB-LA36

*Frame Assembly

~F~" L~Ii,g

*Foot, Leveling
*Closure, Tubing
*Closure, Tubing
*Bumper, Rubber

(deleted)
(added)
(deleted)
(added)
(deleted)

~F'" 115V 1115 CFM, Ro"o, 0' 'MC

'd""""

*Fan, 115V (100 CFM) Torin (deleted)
*Fan, 115V (35 CFM) (added)
*Screw, Phi Pan Hd No. 8-32 x 1.75 (For Rotron
(deleted)
*Screw, Phi Pan Hd No. 8-32 x .38 (added)
*Washer, Split Lock No.8
*Washer, Flat No.8
~pOWE R CO RD ASSEM BL Y 1115V' (deleted)
*POWER CORD ASSEMBLY (120V) (added)
*POWER CORD ASSEMBLY (230V) (deleted)
*POWE R CORD ASSEMBLY (230V) (added)
*Plate, Cover
GStrain Relief (deleted)
*Strain Relief (added)
*Strain Relief
*Capacitor, 33,000 MFD
Ccapacitor, 18,000 MFD (deleted)
*Capacitor, 37,000 MFD (added)
*Capacitor, 14,000 MFD
*Cover, Capacitor (added)
*Spacer, No. 10-32 x .375 x 3.00 (added)
*Screw, Phi Pan Hd No. 10-32 x .50 (added)
*Washer, Split Lock No. 10 (added)
*Washer, Flat No. 10 (added)
*Tie Wrap
*HARNESS ASSEMBLY (Capacitor)
*Bracket, Fuse Mounting (deleted)
*Fuse Holder
*Fuse, Sio-Blo 2 amps
CFuse, Sio-Blo 1 amp (deleted)
*Fuse, Sio-Blo 1.5 amp (added)
*Decal, Fuse
*Fuse, Sio-Blo 3 amp

ECO
CUT-IN
LA36
00001

ACEG

70-09648-01
70-09648-01

VENDOR
USED ON
CODE

00138

70-09648-02

BDFH
00138

70-09648-03

00138

70-09648-04

00138

90-06037-01
90-06690-00
90-06660-00
70-09673-00
70-09673-00
70-09673-01
70-11045-00
74-11607-00
90-08509-00
90-09768-00
90-09572-00
10-11 545-00
10-11643-00
10-10426-00
10-10187-00
74-15114-00
90-06881-00
90-06073-00
90-07906-00
90-06664-00
90-09350-00
70-09895-00
74-11925-00
12-11638-00
90-07216-00
90-07212-00
90-09740-00
74-13384-00
90-07218-00

8-12

70-09648-02

70-09649-00
70-07601-00
90-09685-00
12-11067-00
12-11067-02
90-09567-00
12-09403-01
12-11993-00
12-12581-02
90-06046-01

CODE

REF
FiG
PART NO. NO.

00059
00059
00118

00142
00142
00164

ACEG
JNLQ
BDFH
MRKP

00164

00138
00164
00164
00164
00164
00164
10
00052

00138

FIG

ECO
CUT-IN

&
ITEM
NO.

DESCRIPTION

DEC
PART NO_

LA36
00001

VENDOR
USED ON
CODE

CODE

REF
FICl
PART NO. NO.

29
30
31
32
33
34
35
36
37
38

39
40
41
42
43
44
45

46
47

48
49

50
51
52
53
54
55
56
57

58
59

60
61
62
63

64
65
66
67
68
69
70
71
72
73

*Capacitor,.1 MFD,1000V (deleted)
*Screw, Phi Pan Hd No. 6-32 x.38 (deleted)
*Nut, Kep No. 6-32 (deleted)
[Jumper (deleted)
*Jumper (added)
*Jumper (deleted)
*Jumper
*Jumper (added)
*Filter, EMI (added)
*Cover, EMI Filter (added)
*Grommet, Rubber (added)
*Washer, Ext Tooth No.8 (added)
*Nut, Hex No. 8-32 (added)
*Spacer, NO.8 x .75 (added)
*Washer, Int Tooth (added)
*Grommet (added)
*Grommet (added)

[TRANSFORMER ASSEMBLY ",,"",,
*TRANSFORME R ASSEMBLY (60 Hz) (added)
*TRANSFORMER ASSEMBLY (50 Hz) (added)
*Power Board Assembly

[: Log;' """d "-bly "",,'" ,

*Logic Board Assembly (deleted)
*Logic Board Assembly (added)
*Jumper, 110V
*Jumper, 220V
*Clip, Harness (added)
*Grommet (added)
*Ground Strap (added)
*Nut, Kep No. 8-32 (added)
*Tubing, Heat Shrink (added)
*Cable, Paper out (added)
*Switch, Rework (added)
*Paper Guide (added)
*Screw, Phi Pan Hd No. 4-40 x 9/16 (added)
*Nut, Keps No. 4-40 (added)
*Foam, Protective
*Door, Cabinet
*Bushing, Snap in Nylon (deleted)
*Bushing, Nylon (deleted)
*Screw, Hex Hd Cap No. 3/8-16 x 1.0 (deleted)
*Pivot, Door (added)
*E-Ring, External (added)
*Screw, Special (added)
*E-Ring, External (added)
*Catch, Door Strike
*Catch, Door Latch
*Decal, Ground (added)
*Fuse Holder (added)
*Spacer, Fuse Holder (added)

10-00034-00
90-06022-01
90-06560-00
70-10001-04
70-10001-08
70-10001-02
70-10001-12
70-10001-11
12-12003-00
74-13286-00
90-07013-00
90-08072-00
90-06561-00
90-07868-00
90-08292-00
90-09 718-02
90-09718-03
70-09779-00
70-09779-01
70-09779-02
54-10805-00
M7722
M7723
M7728
70-09905-01
70-09905-02
90-08340-00
90-09718-00
90-06990-00
90-06563-00
91-07253-09
70-11657-00
74-12424-00
74-12158-00
90-08033-01
90-06557-00
74-14144-00
74-11120-00
90-09561-00
90-09565-01
90-08922-09
74-15068-00
90-09773-00
74-15067-00
90-09772-00
90-09571-00
90-09571-01
36-12680-00
12-12893-00
74-15374-00

8-13

00052
00052
00052
00139
00139
00177
00161
00052
00052
00052
00052
00163
00163
00156
00156
00156
00138
00138

A-H
JNKP
LQMR

8
8A
8A

00103
00135

00162
00162
00021
00021
00161
00162
00162
00162
00162
00162

00164
00164
00164
00164
00164
00164
00164

00162
00177
00177

IPB-LA36

275
28W
70N

LA36-07A

Figure 3 . Prtnter
.
Mechanism A ssembly

8-14

IPB-LA36

FIG
&
ITEM
NO.

DESCRIPTION
PRINTER MECHANISM ASSEMBLY

31
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

30
31
32
33
34
35
36
37

38
39
40
41
42
43
44

IPB-LA36

*Plate, Side (LH)
*Plate, Side (RH)
*Shaft, Tractor Drive
*Shaft, Tractor Support
CTRACTOR ASSEMBLY (RH) (deleted)
*TRACTOR ASSEMBLY (RH) wI Lock (added)
**Shaft, Screw (deleted)
~Retaining Ring (added)
**Retaining Ring (deleted)
*Screw, Tractor Lock (added)
C,TRACTOR ASSEMBLY (LH) (deleted)
*TRACTOR ASSEMBLY (LH) w/Lock (added)
*Washer, Flat No. 10 (deleted)
*Bushing, Tractor Shaft Retaining
* Retaining Ring
*Retaining Ring Push-on
*Retaining Ring (deleted)
*Retaining Ring Prong Lock
*Collar, Side Plate
*Hub, Clutch
*Gear, Drive Clutch
*Washer, Clutch
*Knob, Line Feed
·Spring, Compression
*Retaining Ring
*Adapter, Line Feed
*Retaining Ring (added)
r-*Spring, Compression (added)
~Spring, Compression (deleted)
*Washer, .697 00 x .375 10 x .062 (added)
~Washer, .697 00 x .375 10 x .062 (deleted)
*Screw, Nylock 6-32 x .50 (deleted)
·Screw, Phi Pan Hd No. 6-32 x .38 (added)
....·Washer, Flat No.6
·Washer, Int Tooth Lock NO.6
*Shaft, Carriage
·CARRIAGE ASSEMBLY
·Bushing, Plain
*PRINT BAR ASSEMBLY
*Pivot, Lower
* Ratchet, Pivot
*Screw, Phi Pan Hd No. 8-32 x .38
*Washer, Split Lock No.8
·Washer, Flat No.8
*RIBBON CHASSIS ASSEMBLY
*Retaining Ring
*Frame, Ribbon Idler w/Bushing
*Retaining Ring
*Washer, Flat No. 10
·Washer, Split Lock No. 10

DEC
PART NO,

ECO
CUT-IN
LA36
00001

70-09696-00
74-11028-01
74-11028-02
74-11075-00
74-11076-00
70-09693-03
12-11662-05
74-11908-00
90-09582-00
90-09582-00
74-14433-00
70-09693-04
12-11662-04
90-06664-00
74-11425-00
90-09579-00
90-09257-00
90-07975-00
90-09581-00
74-11098-03
74-11441-00
74-11440-00
74-11443-00
74-11437-00
90-09592-00
90-09580-02
74-12535-00
90-09644-00
12-12353-00
12-12353-00
90-07858-00
90-07858-00
90-09591-01
90-06022-00
90-06653-01
90-06633-00
74-11033-00
70-09692-00
74-11108-00
70-10683-00
74-11439-00
74-11103-00
90-06037-01
90-06690-00
90-06660-00
70-09689-00
90-09580-00
74-11576-00
90-09273-00
90-06664-00
90-07906-OC

8-15

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
lA

00173
00173
00039
00173

00173
00028

00028

00028
00154
00173
00154
00173
00028

FIG

ECO
CUT-IN

&
ITEM
NO.

DESCRIPTION

DEC
PART NO.

*Screw, Socket Hd Cap No.1 0-32 x .50
*Spring, Compression
*Nut, Lock No. 8-32
*Screw, Socket Hd Cap No. 8-32 x 1.00
*Spring (added)
*Wick (added)
* Reservoir, Oil (added)
*DC MOTOR and ENCODE R ASSEMBLY
*Belt, Timing (deleted)
*Belt, Timing (added)
* Retainer, Bumper Spring
*Spring, Carriage Bumper
*Screw, Phi Pan Hd No. 10-32 x 2.00
*IDLER GEAR ASSEMBLY
*Shaft, Idler
*Standoff, Hex .620
*Washer, Flat No.8 x .062
*Stepping Motor, 16 V DC
*Nut, Kep No. 8-32
*Screw, Hex Hd Machine No. 1/4-20 x .50
*Washer, Split Lock No. 1/4
*Washer, Flat No. 1/4
*RIBBON DRIVE ASSEMBLY
*Spring, Compression
*Ground Strap
*Decal, Ground Symbol (added)
*Nut, Kep No. 6-32
*Speaker, 2-1/2 in. Perm Magnet

90-06346-08
90-09673-00
90-09061-00
90-07988-08
74-13699-00
74-13698-00
74-13672-00
70-09691-00
12-11583-00
12-11583-01
74-11412-00
74-11816-00
90-06081-01
70-09694-00
74-11575-00
90-09583-00
90-06662-00
12-11563-00
90-06563-00
90-06241-09
90-07797-00
90-06676-00
70-09690-00
90-09578-00
70-10001-05
36-12680-00
90-06560-00
12-10299-00

LA36
00001

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.

345
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63

64
65
66
67
68
69
70
71

8-16

00082
00082
00082
9
00155

00166

IPB-LA36

~DmDDmD\

PARTS LlS':/

'---2

LA36-09A

4 Ribbon Chassis Assembly
F,gure,

8-17

IPB-LA36

FIG
&
ITEM
NO.
41
2
3
4
5
6
7
8

DESCRIPTION

DEC
PART NO.

RIBBON CHASSIS ASSEMBLY

70-09689-00

*Chassis, Ribbon w/lnserts
*Base Assembly, Ratchet
*Spring, Upper Pawl
*Spring, Main Pawl
*Pivot, Ratchet
*Washer, Ratchet
*Screw, Phi Pan Hd No. 8-32 x .31
[*washer, Lock Int Tooth No.8 (deleted)

70-09680-00
70-09697-00
74-11105-00
74-11090-00
74-11103-00
74-11061-00
90-06036-01
90-06634-00

*Washer, Split Lock No.8
*Washer, Flat No.8
*Guide, Shoe
*Screw, Phi Pan Hd No. 8-32 x .38, Self Tapping
*Collar, Side Plate
*Disk, Friction

90-06690-00
90-06662-00
74-11419-00
90-09586-01
74-11098-02
74-11405-00

*Wheel, Ratchet
*Driver, Spool

Com,=;oo (deleted)

74-11432-00
74-11048-00
90-09584-00

*Spring, Compression (added)
*Washer, Brake (deleted)

1 2-12353-00
74-11106-00

*Retaining Ring (deleted)

90-09580-00

19
20
21
22

* Interposer, L.H.
* Interposer, R.H.
*Spring, Interposer

[WMh'" Flo< No, 6 (deleted)

74-11058-01
74-11058-02
74-11087-00
90-06707-00

23
24

*Washer, Flat No.6 (added)
*Sensor, Reverse
*"U" Clip (added)

90-06634-00
74-11060-00
90-09748-00

·25
26

*Cap, Standoff Spool
*Screw, Phi Pan Hd No. 8-32 x 2.75 (added)

74-12976-00
90-06050-01

*Washer, .687 x .375 (added)

90-07858-00

*Washer, .625 x .200 (added)

90-06668-00

*Nut, Elastic Stop No. 8-32 (added)

90-09061-00

9
10
11
12
13
14
15
16

IPB·LA36

[5";0',

8-18

ECO
CUT-IN
70-09689
00001

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
3

LA36
00113

LA36
00083

LA36
00116
LA36
00079
LA36
00079

LA36
00113

LA36
00143
LA36
00083
LA36
00083
LA36
00083
LA36
00083

VENDOR
DEC
PART NO

DESCRIPTION
51

2
3
4
5
6
7

8
9
10

11
12
13
14
15
16
17

RI8BON DRIVE A SSEMBLY

70-09690-00

·Bracket ,Ibbon
R·
.B
Dr"
earin S
Ive
• Shaft g,. elf Aligning
,Ribbon Idl
.Ribbon Eccent . er
.Rod, End
riC, w/Clutch

74-11113-00
12-11649-00
74-11068-00
74-11578-00
74-11084-00
12-11650-00
90-09651-08
90-06036-01
90-06563-00
74-11035-02
12-12446-00
74-11124-00
90-08045-08
90-08957-00
74-11046-00
90-09580-00
74-11123-00
74-11426-00

·Bearing
·Screw, SOC Hd
.Screw Phi P Cap No. 4-40 x 12
.N ut, Kep
'
.
N an Hd N o. 8-32 x .31

.p I

0.8-32
u ley Ti .
.Pulley' Tim~ng (deleted)
.Clam' mmg (added)
*
p, Collar
• Screw,So
c Hd Ca N
• Nut, Hex No. 6-3; o. 6-32 x .38

Push rod
-Retaining R·
*W
mg
* a~her, Eccentric
Spnng, Backstop

USED ON
CODE

CODE

REF
F,IG
NO •

PART NO

LA36-0BA

Figure 5. Ribbon Drive
. Assembly

8-19

IPB-LA36

FIG
&
ITEM
NO.

DESCRIPTION

DEC
PART. NO.

ECO
CUT-IN
70-09692
00000

VENDOR
USED ON
CODE

CODE

REF
FIG·
PART NO. NO.

CARRIAGE ASSEMBLY

70-09692-00

*Carriage
*Lever. Carriage Adjustment
*Bushing, Eccentric
*Idler, Carriage Ribbon, w/ldler

74-11109-00
74-11110-00
74-11107-00
74-11577-00

5
6

*Washer, Flat No.6
*Retaining Ring

90-06653,00
90-08528-00

1
2
3

LA36
00011

6~
I

--{9
I

LA36-12

Figure 6. Carriage Assembly

8-20

IPB·LA36

FIG

&
ITEM
NO.
71
2
3
4
5
6
7

DESCRIPTION

DEC
PART NO.

IDLER GEAR ASSEMBLY

70-09694-00

*Bracket, Gear
*Gear, 48 Tooth
*Tube, Idler
*Screw, Phi Pan Hd No. 8-32 x 1.00
·Washer, Flat No.8
*Washer, Split Lock No.8
*Nut, Hex No. 8-32

74-11420-00
12-11656-00
74-11424-00
90-06043-01
90-06666-00
90-06690-00
90-06561-00

ECO
CUT-IN
70-09694
00000

VENDOR
USED ON
CODE

CODE

REF
r:;IG
PART NO. NO.
3

LA36-13

Figure 7. Idler Gear Assembly

8-21

IPB-LA36

FIG
&
ITEM
NO.
81
2
3
4
5
6
7
8
9
10

ECO
CUT-IN

DEC
PART NO.

LA36
00001

TRANSFORMER ASSEMBLY (deleted)

70-09779-00

00138

*Power Transformer (deleted)
*Connector (P3) Pin Housing, 8 Pin Mate-N-Lok
*Terminal, Pin Contact
*Terminal, Quick-Connect (deleted)
*Terminal, Quick-Connect (deleted)
*Connector (J1) Free-Hanging, 4 Socket
Mate-N-Lok (deleted)
*Terminal, Socket Contact (deleted)
*Connector (J2, J3) Socket Housing AMP
(deleted)
*Terminal, Socket Contact (deleted)
*Terminal, Ring Tongue

16·11482-00
12-09340-01
12-09378-00
90-07919-00
90-07917-00
12-10821-04

00138

12-09379-00
12-10820-01

00124
00124

12-10820-02
90-07928-00

00124

DESCRIPTION

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
2

00052
00124
00124

LA36-06

Figure 8. Transformer Assembly

8-22

IPB-LA36

FIG
&
ITEM
NO.
8A-

1
2
3
4
5
6
7
8
9
10
11

DEC
PART NO.

DESCRIPTION
TRANSFORMER ASSEMBLY
Transformer Assembly (60 Hz)
Transformer Assembly (50 Hz)

70-09779-01
70-09779-02

*Power Transformer (60 Hz)
*Power Transformer (50 Hz)
*Connector (P3), Pin Housing, 8 Pin Mate-N-Lok
*Terminal, Pin Contact
*Connector (J2) Pin Housing, 3 Pin Mate-N-Lok
*Connector (J1) Pin Housing, 4 Pin Mate-N-Lok
*Terminal, Pin Contact
*Terminal, Ring Tongue
*Cable Tie
*Tubing, Heat Shrinkable
*Tubing, Extruded
*Terminal, Quick Connect

16-12522-00
16-12521-00
12-09340-01
12-09378-00
12-10821-03
12-09351-04
12-09379-00
90-07928-00
90-07031-00
91-07253-09
91-07244-00
90-07970-00

ECO
CUT-IN
LA36
00138

VENDOR
USED ON
CODE

CODE

REF
FtG
PART NO. NO.
2

8
10

LA36-06A

Figure BA Transformer Assembly

8-23

IPB-LA36

FIG
&
ITEM
NO_

DEC
PART NO.

DESCRIPTION
D.C. MOTOR and ENCODER ASSEMBLY

70-09691-00

1
2
3
4
5
6
7
8
9

*Motor, D.C.
*Encoder Base Harness Assembly
*Screw, Phi Pan Hd No. 4-40 x .75
*Clamp, Collar
*Pulley, Timing
*Screw, Soc Hd Cap No. 6-32 x .38
*Nut, Hex No. 6-32
*Disk Assembly
*Clamp, Cable

70-09780-00
70-09777-00
90-06015-01
74-11124-00
74-11035-01
90-08045-08
90-08957-00
70-09778-00
90-07079-00

10
11
12
13
14
15
16
17
18
19
20
21
22

*Screw, Phi Pan Hd No. 8-32 x .31
*Washer, Split Lock No.8
*Washer, Flat No.8
*Terminal, Strip Tie Down
*Capacitor (,01 MFD)
*Jumper
*Jumper
*Jumper
*Jumper
*Screw, Phi Pan Hd No. 6-32 x .18
*Washer, Ext Tooth No.6
*Decal, Ground
*Dust Cover, Encoder

90-06036-01
90-06090-00
90-06661-00
90-07004-00
10-01010-01
70-10001-09
70-10001-10
70-10001-07
70-10001-05
90-08020-01
90-07649-00
36-12680-00
74-11416-00

ECO
CUT-IN

VENDOR
USED ON
CODE

LA36
00166

CODE

REF
FIG
PART NO. Nd.
3

?(,
1,
"

6
4

18
19

22
LA36-18

Figure 9. D. C. Motor and Encoder Assemblv

8-24

IPB-LA36

FIG
&
ITEM
NO.
101
2
3

4
5
6

DEC
PART NO.

DESCRIPTION
CAPACITOR HARNESS ASSEMBLY

70-09895-00

·Connector, P2, Pin Housing, 8 Pin Mate-N-Lok
·Terminal, Pin Contact
·Connector, Solderless
·Connector, Solderless
·Tie Wrap
·Tie Wrap, Screw Down (deleted)

12-09340-01
12-09378-00
90-07928-00
90-07926-00
90-07031-00
90-07033-00

ECO
CUT-IN
70-09895
00000

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
2

LA36
00181

LA36·05

Figure 10. Capacitor Harness Assembly

8-25

IPB-LA36

FIG
&
ITEM
NO.
11-

1
2
3
4
5
6

ECO
CUT-IN

DEC
PART NO.

70-10000
00000

USED ON
CODE

CABLE ASSEMBLY (LA36 Keyboard) (deleted)

70-10000-00

LA36
00136

A-H

*Cable, 24 Conductor (No. 22 AWG)
*Housing, Termination Berg
*Socket, Crimp
*Label, (THIS SIDE UP)
*Strain Relief
~onnector, Solderless (deleted)
*Connector, Solderless (added)

17-00011-01
12-10918-15
12-10089-07
36-11567-00
12-11166-00
90-07917-00
90-07970-00

DESCRIPTION

*Tie Wrap

VENDOR
CODE

REF
FIG
PART NO. NO.
1

LA36
00136

90-07031-00

LA36-16

Figure 11_ Cable Assembly (LA36 Keyboard)

8-26

IPB-LA36

FIG
&
ITEM
NO.

DEC
PART NO.

DESCRIPTION

11A-

CABLE ASSEMBLY (LA36 Keyboard)

70-11519-00

1
2
3
4
5
6

*Cable, 24 Conductor (No. 22 AWG)
*Connector, Housing 44 Pin Berg
*Terminals, Socket Crimp
*Strain Relief
*Label (THIS SIDE UP)
*Tie Wraps

17-00011-01
12-10918-15
12-10089-07
12-11166-00
36-11567-00
90-07031-00

ECO
CUT-IN
LA36
00136

VENDOR
USED ON
CODE
J-R

CODE

REF
FIG

PART NO.

1\'10.
1A

2
3
4

LA36-16A

Figure 11A. Cable Assembly (LA36 Keyboard)

8-27

IPB-LA36

FIG
&
ITEM
NO.
12-

1
2
3
4
5
6
7
8
9

ECO
CUT-IN

VENDOR

DESCRIPTION

DEC
PART NO_

70-09750
00001

USED ON
CODE

KEYBOARD BEZEL ASSEMBLY (deleted)

70-09750-01

LA36
-00163

EFGH

*Bracket, Bezel
*Spacer, Hex No.8 x 1.00
*Spacer, Hex No.8 x .75
*LK02 KEYBOARD ASSEMBLY
*Nut, Kep No. 8-32
*Switch, Rocker (DPST)
*Switch, Rocker (3 Position)
*Washer, Split Lock No.6
*Screw, Phi Pan Hd No. 6-32 x .31

74-11427-01
90-09285-00
90-07868-00
LK02-00.
90-06563-00
12-11621-00
12-11732-00
90-07801-00
90-06021-01

CODE

REF
FIG
PART NO. NO.
1

EFGH

(See IPB Manual EK-LK02-IP-)

I
I

LA36-14

Figure 12. Keyboard Bezel Assembly

8-28

IPB-LA36

FIG
&
ITEM
NO.
12A1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

DEC
PART NO.

DESCRIPTION

ECO
CUT-IN
LA36
00163

VENDOR
USED ON
CODE

KEYBOARD BEZEL ASSEMBLY

70-09750-01

NPOR

"Bracket, Bezel
"Spacer, Hex No.8 x 1.00
"Spacer, Hex No.8 x .75
"Nut, Kep No. 8-32
"LK02 KEYBOARD ASSEMBLY
"Control Panel Cable
"FRONT CONTROL PANEL ASSEMBLY
"" Keycap Set
""Front Control Panel Assembly
"Switch, Rocker (DPST)
"Grommet
*Screw, Phi Pan Hd No. 6-32 x .31
·Washer, Split Lock No. 6-32
"Harness Clip
"Jumper
*Washer, External Tooth No.8
*Decal, Ground Symbol
"Washer, Flat Nylon No.8

74-11427-01
90-09235-00
90-07868-00
90-06563-00
LK02-oo
70-08612-OK
70-11 525-00
12-12287-E3
54-11727-00
12-11621-00
90-09713-01
90-06021-01
90-07801-00
90-08340-00
70-10001-05
90-08072-00
36-12680-00
90-06708-00

NPOR

J-R
J-R
J-R

REF
F;IG
PART NO. NO.

CODE

(See IPB Manual EK-LK02-lp·)

,_y17
<'(Q'>

1 1 - -_ _-.111

i~
2-------1-1:

I
I

V4
LA36-14A

Figure 12A. Keyboard Bezel Assembly

8-29

IPB-LA36

FIG
&
ITEM
NO.

DESCHIPTION

ECO
CUT-IN

VENDOR

DEC
PART NO.

70-09750
00001

USED ON
CODE

REF
FI.G
PART NO. NO.

CODE

13-

KEYBOARD BEZEL ASSEMBLY (deleted)
(With Cursor Control)

70-09750-02

LA36
-00163

ABCD

*LK03 KEYBOARD ASSEMBLY (deleted)

LK03-00

LA36
-00136

ABCD (See IPB Manual EK-LK03-IP- )

2
3
4
5
6
7
8
9
10
11

*LK02 KEYBOARD ASSEMBLY
*Cable, Keyboard
**Cable, 16 Conductor
**Connector, Dual In Line 16 Pin
*Bracket, Bezel
*Spacer, Hex No.8 x 1.00
*Spacer, Hex No.8 x .75
*Nut, Kep No. 8-32
*Switch, Rocker (DPST)
*Switch, Rocker (3 Position) (deleted)

LK02-00
70-08612-0D
91-07738-00
12-10722-00
74-11427-02
90-09825-00
90-07868-00
90-06563-00
12-11621-00
12-117 32-00

12
13

*Washer, Split Lock No.6
*Screw, Phi Pan Hd No. 6-32 x .31

90-07801-00
90-06021-00

(See IPB Manual EK-LK02-IP- )

A-H

ABCD

LA36
-00136

10-...;;;:--'-.--,
12

I
I

9
LA36-15

Figure 13. Keyboard Bezel Assembly (W/Cursor Contro/)

8-30

IPB-LA36

FIG
&
ITEM
NO.
13A-

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

DEC
PART NO.

DESCRIPTION
KEYBOARD BEZEL ASSEMBLY
(With Cursor Control)

70-09750-02

*Bracket, Bezel
*LK02 KEYBOARD ASSEMBLY
*LK03A KEYBOARD ASSEMBLY
*Spacer, Hex No.8 x 1.00
*Spacer, Hex No.8 x .75
*Nut, Kep No. 8-32
*Cable (Keyboard to Cursor)
*Cable (Control Panel to Keyboard)
*FRONT CONTROL PANEL ASSEMBLY
**Keycap Set
**Front Control ;anel Assembly
*Grommet
*Switch, Rocker (DPST)
*Screw, Phi Pan Hd No. 6-32 x .31
*Washer, Split Lock No.6
*Harness Clip
*Jumper
*Washer, External Tooth No.8
*Decal, Ground Symbol
*Washer, Flat Nylon No.8

74-11427-02
LK02-00
LK03A-00
90-09285-00
90-07868-00
90-06563-00
70-08612-0D
70-08612-0K
70-11525-00
12-12287-00
70-11727-00
90-09713-01
12-11621-00
90-06021-01
90-07801-00
90-08340-00
70-10001-05
90-08072-00
36-1 2680-00
90-06708-00

ECO
CUT-IN
LA36
00163

VENDOR
USED ON
CODE

CODE

REF
FW
PART NO. NO.

JKLM

(See IPB Manual EK-LK02-lp· )
J-R
JKLM (See IPB Manual EK-LK03A-IP-)

~.,-

_ _ 19

14S
15W
13

4 -_ __

~6
LA36-15A

Figure 13A. Keyboard Bezel Assembly (w/Cursor Contro/)

8-31

IPB-LA36

FIG
&
ITEM
NO.
14-

2
3

ECO
CUT-IN

VENDOR

DEC
PART NO.

BC05-F
00001

USED ON
CODE

CABLE ASSEMBLY (BC05F Interface) (deleted)

BC05F-15

LA36
-00165

ABEF

*Cable,4 Conductor (No. 22 AWG)
*Connector (P1, P2) Pin Housing, Mate·N·Lok
*Terminal, Pin Contact

91-07706-00
12-09340·01
12-09378·03

DESCRIPTION

CODE

REF
FI.G
PART NO. NO.
1

-DEC

r---~-_~~

LA36·17

Figure 14. Cable Assembly (BC05F Interface)

8-32

IPB-LA36

EK-LK02-IP-002

ILLUSTRATED
PARTS
BREAKDOWN

LK02
KEYBOARD

HOW TO USE THE IPS
GENERAL
This IPB is compiled following the organization and nomenclature
of the engineering drawing structure.
MAJOR ASSEMBLY LOCATOR
The Major Assembly Locator (fir-a illustration) is an index that
provides a description and a figure reference for all illustrations used
in this manual.
INDENTED PARTS LIST
This manual identifies each assembly being broken down (figure
reference callout), and all parts of that assembly. Further
breakdown of an assembly is shown by an asterisk (*) preceding the
item callouts in the Description Column. The number of asterisks
preceding an item is used to denote the subordination of that item
with respect to the Major Assembly. A single asterisk preceding an
item description indicates that the item is part of the major
assembly being illustrated. Items that are subordinate to single
asterisks items, are denoted by two asterisks (**) and immediately
follOW the related single asterisk item. Additional asterisks are used,
as required, to denote further subordination. This system of part
identification, provides a means for the user to identify the next
higher assembly item and make alternate selections for parts when
the required replacement part or assembly is not immediately
available.
COLUMN CALLOUT DESCRIPTION
Figure & Item - I ndicates the figure number and item number of
each part.

ECO Cut-In - The notation at the top of this column indicates the
ECO level of the system (option), at which the IPB was initially
prepared. Subsequent ECO level designations, that modify existing
parts or add new parts to the device, are inserted in the ECO Cut-I n
column next to the part that is added or modified. A bracket ([)
preceding the item description is used to indicate the parts affected
by ECO's.
Vendor Code/Part No. - Indicates vendor parts that are not stocked
by DEC. Refer to the Field Service Spares Catalog (vendor part
number to DEC part number) for the vendor code cross-reference.
Used On Code - Letters in this column correspond to the variation
codes assigned in Figure 1. Parts with an Alpha notation(s) are used
only in those option variations. A blank indicates that the part is
used on all option variations.
Ref Fig No. - A cross reference between illustrations. For each
Major Assembly, the number in this column denotes the figure of
the next higher assembly. For all subassemblies, the number in this
column denotes the figure showing additional detailed breakdown.
SYMBOL USAGE
Hardware Designators - Alpha designators for screws (S), washers
(W), nuts (N), and retaining rings (R) are inserted after the item
number callouts on the illustration when stacked item numbers are
used.
Attaching Hardware - The @ symbol is inserted before any part
that is used as attaching hardware. Attaching hardware is denoted as
those parts that are not an integral part of the referenced assembly.

Description Lists the name of the part and pertinent
specifications (when required). Asterisks preceding the description
denote the subordination of the part to the next higher assembly.

(NFR) Not Field Repairable - The (NFR) symbol is inserted after
any assembly that is not to be field dismantled.

DEC Part No. - Lists the DEC part ordering number. A blank in
this column indicates a DEC part number was not assigned at the
time of publication.

Other Symbols - Any other symbols that are required for kits,
accessories, etc., will be explained and appear as part of the item
description.

REVISION HISTORY
ECO LEVEL

PRINTING
2nd Printing

LK02
54-10736
70-09892

00000-00001
00001-0003A

DATE

PAGES AFFECTED

1-30-76

This 2nd Printing EK-LK02-IP-002
SUPERSEDES 1st Printing DEC-LK02-IPB-l

00000-00000

(NOTE THAT THE DOCUMENT NO.
OF THIS IPB HAS CHANGED)

Copyright © 1974,1976 by Digital Equipment Corporation
DEC reserves the right, without notice, to make substitutions and
modifications in the specifications of products documented in this
manual and further reserves the right to withdraw any of these
products from the market without notice.

Printed in U.S.A.

8-33

LK02 KEYBOARD ASSE\IIIBLY
Fig. 1

d)
\
\

Fig. 3

Fig. 2-2A-2B

LK02-0 1

Major Assembly Locator, LK02 Keyboard
\PS_LK02

8·34
2

thru

60
/

cD\
\

U<.02-01

8·35

FIG

&
ITEM
NO.
11
2
3
4
5
6
7
8
9
10

11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

34
35
36
37

39
40
41
42
43
44
45
46
47
48
49

IPB-LK02

DESCRIPTION

DEC
PART NO.

LK02 KEYBOARD ASSEMBLY

LK02-00

*KEYBOARD MODULE
*KEY CAP, SINGLE Complete Set
(Includes Caps Item 3 thru Item 60)
**Key Cap, Single A
**Key Cap, Single B
**Key Cap, Single C
**Key Cap, Single D
**Key Cap, Single E
**Key Cap, Single F
**Key Cap, Single BELL G
**Key Cap, Single H
**Key Cap, Single I
**Key Cap, Single J
**Key Cap, Single VT K
**Key Cap, Single FF L
**Key Cap, Single M
**Key Cap, Single N
**Key Cap, Single 0
**Key Cap, Single P
**Key Cap, Single Q
**Key Cap, Single R
**Key Cap, Single S
**Key Cap, Single T
**Key Cap, Single U
**Key Cap, Single V
**Key Cap, Single W
**Key Cap, Single X
**Key Cap, Single Y
**Key Cap, SingleZ
**Key Cap, Single ()
HKey Cap, Single! 1
**Key Cap, Single @ 2
**Key Cap, Single # 3
**Key Cap, Single $ 4
**Key Cap, Single % 5
**Key Cap, Single ~ 6
**Key Cap, Single & 7
**Key Cap, Single * 8
**Key Cap, Single ( 9
**Key Cap, Single) 0
**Key Cap, Single + ;
**Key Cap, Single - **Key Cap, Single [ 1
**Key Cap, Single RETURN
**Key Cap, Single LF
**Key Cap, Single REPEAT
**Key Cap, Single ESC (SEll
**Key Cap, Single TAB
**Key Cap, Single CTRL
**Key Cap, Single - \
**Key Cap, Single: ;

54-10736-00
12-12287-62

ECO
CUT-IN
LK02
00000

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.

12-12287-01
12-12287-02
12-12287-03
12-12287-04
12-12287-05
12-12287-06
12-12287 -07
12-12287-08
12-12287-09
12-12287-10
12-12287-B4
12-12287-B5
12-12287-13
12-12287-14
12-12287-15
12-12287-16
12-12287-17
12-12287-18
12-12287-19
12-12287-20
12-12287-21
1'2-12287-22
12-12287-23
12-12287-24
12-12287-25
12-12287.-26
12-12287 -27
12-12287-28
12-12287-29
12-12287-30
12-12287-31
12-12287 -32
12-12287-33
12-12287-34
12-12287-35
12-12287-36
12-12287-37
12-12287-38
12-12287-39
12-12287-40
12-12287-41
12-12287-42
12-12287-43
12-12287 -44
12-12287-45
12-12287-46
12-12287-47
12-12287-48

8-36

FIG
&
ITEM
NO.

ECO
'CUT-IN
DESCRIPTION

DEC
PART NO.

**Key Cap. Single" •
**Key Cap. Single DELETE
**Key Cap. Single \
**Key Cap. Single SHIFT
**Key Cap. Single? I
**Key Cap. Single> .
**Key Cap. Single < .
**Key Cap. Single CAPS LOCK
**Key Cap. Single BACK SPACE
**Key Cap. Single BREAK

12-12287-49
12-12287-50
12-12287-51
12-12287-52
12-12287-53
12-12287 -54
12-12287-55
12-12287-56
12-12287 -57
12-12287-58

LK02
00000

VENDOR
USED ON
CODE

CODE

REF
FlG
PART NO. NO.

151
52
53
54
55
56
57

58
59
60

8-37

IPB-LK02

FIG

&
DESCRIPTION

DEC
PART NO_

LK02 KEYBOARD MODULE (ETCH REV. D)

54-10736-00

*Board, Etched Circuit
*Capacitor (C3) .01JJF, 1OOV, 10% Mylar
*Capacitor (C4, C5, C7, C8, C9, C13) .01 fJF,
100V, 20% Disc
*Capacitor (Cl) 1 fJF, 25V Tant
*Capacitor (C2, C6) 180 pF, 100V, 5% Mich
*Capacitor (Cl0, C12) 10 fJF, 20V, 10% Tant
*Oiode (04-09,011-045,047-062) 0664
*Transistor (Q3) DEC 3009B
*Switch (Sl) (OPST)
*Socket (Jl) IC 16 Pin
*Connector (J2) Right Angle Header
*Socket (XE I) Rom
*I.C. (E2) 7404
*I.C. (E3) 7400
*I.C. (E7) 7430
*I.C. (E5, E6) 7437
* I.C. (E4) 9601
*I.C. (Ell ROM
*Selector, Phenolic Switch
*Screw, Phi Self Tapping No. 4-40 x 3/16
*63 KEYSWITCH ARRAY
*Resistor (Rl, R4, R5, R9, Rl0) lK,l/4W, 5%
*Resistor (R6, R 11) 3.9K, 1/4W, 5%
*Resistor (R3) 22K, 1/4W, 5%
*Resistor (R2) lOOK, 1/4W, 5%
*Resistor (R7, R8) 2 ohm, 1 /2W, 5%

50-10735-00
10-05784-00
10-01610-01

ITEM
NO.
21
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

15 16

5 23 14 22

ECO
CUT-IN
54-10736
00001

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
1

10-1 0866-01
10-00020-00
10-04813-00
11-00114-00
15-03100-00
12-10919-00
12-10025-00
12-09941-00
12-10947-00
19-09686-00
19-05575-00
19-05570-00
19-10091-00
19-09373-00
21-11634-00
74-09532-00
90-09159-00
70-09892-00
13-00365-00
13-00444-00
13-01808-00
13-02466-00
13-09421-00

17 13 3

~=====~~~~~~--I---r~"
21

ETCH REV. D
LK02-02

Figure 2.

LK02 Keyboard Module (Etch Rev. D)

8-38

IPB-LK02

FIG
&
ITEM
NO.

DESCRIPTION

DEC
PART NO.

2A-

LK02 KEYBOARD MODULE (ETCH REV. E)

54-10736-00

1
2
3

*Board, Etched Circuit
*Capacitor (C3) .01 J.lF, 100V, 10% Mylar
*Capacitor (C4, C5, C7, C8, C9, C13) .01 J.lF,
100V, 20% Disc
*Capacitor (C1) 1 J.lF, 25V Tant
*Capacitor (C2, C6) 180 pF, 100V, 5% Mich
*Capacitor (C10, C12) 10J.lF, 20V, 10% Tant
*Oiode (05-09, 011-45, 047-61) 0664
*Transistor (Q3) DEC 3009B
*Socket (J1, J3) I.C. 16 Pin
*Connector (J2) Right Angle Header
CSocket (XEI) Rom'
(deleted)
*Socket (XEI) Rom
(added)
*I.C. (E2) 7404
*I.C. (E3, E8) 7400
*I.C. (E5, E6) 7437
*I.C. (E4) 9601
(deleted)
CI.C. (E1) Rom
*I.C. (E 1) Rom
(added)
*I.C. (E7) 7410
*63 KEYSWITCH ARRAY
*Resistor (R7, R8) 2 ohms, 1/2W, 5%
*Resistor (R1, R3, R4, R5, R10-14) 1K,
1/4W,5%
*Resistor (R6) 3.9K, 1 /4W, 5%
*Resistor (R9) 22K, 1/4W, 5%
*Resistor (R2) 100K, 1/4W, 5%

50-10735-90
10-05784-00
10-01610-01

4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

10-1 0866-01
10-00020-00
10-04813-00
11-00114-00
1 5-031 00-00
12-11813-00
12-09941-00
12-10947-00
12-12385-00
19-09686-00
19-05575-00
19-10091-00
19-09373-00
21-11634-01
23-002C 1-00
19-05576-00
70-09892-00
13-09421-00
13-00365-00

ECO
CUT-IN
54-10736
00002

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
1

oo02B

0OO2B
3

13-00444-00
13-01803-00
13-02466-00

ETCH REV. E

Figure 2A.

LK02-2A

LK02 Keyboard Module (Etch Rev. E)

8-39

IPB-LK02

FIG

&
ITEM
NO.

DESCRIPTION

DEC
PART NO.

2B-

LK02 KEYBOARO MOOULE (ETCH REV F)

54-10736-00

1
2
3

*Board, Etched Circuit
*Capacitor (C3) .01 J.lF, 1OOV, 10% Mylar
*Capacitor (C4, C5, C7, C8, C9, C13) .01 J.lF,
100V, 20% Oisc
*Capacitor (C1) 1 J.lF, 25V Tant
*Capacitor (C2) 180 pF, 1OOV, 5% Mich
*Capacitor (C10, C12) 10 J.lF, 20V, 10% Tant
*Oiode (05-09, 011-045, 047-061) 0664
*Transistor (Q3) OEC 3009B
*Socket (J1, J3) IC 16 Pin
*Connector (J2) Right Angle Header
*Socket (XE I) Rom
*I.C. (E2) 7404
*I.C. (E3, E8) 7400
*I.C. (E5-E6) 7437
*I.C. (E4) 9601
*I.C. (E 1) Rom
*I.C. (E7) 7410
*63 KEYSWITCH ARRAY
*Resistor (R7, R8) 2 ohm, 1/2W, 5%
*Resistor (R1, R3-R5, R10-R14) 1K,
1/4W,5%
*Resistor (R6) 3.9K, 1/4W, 5%
*Resistor (R9) 22K, 1/4W, 5%
*Resistor (R2) lOOK, 1/4W, 5%
*Capacitor (C6) 1,000 pF, 1OOV, 5% Mich

50-10735-00
10-05784-00
10-01610-01

4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

ECO
CUT-IN
54-10736
00003

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
1

10-1 0866-0 1
10-00020-00
10-04813-00
11-00114-00
15-03100-00
12-11813-00
12-09941-00
12-12385-00
19-09686-00
19-05575-00
19-10091-00
19-09373-00
23-002C1-00
19-05576-00
70-09892-00
13-09421-00
13-00365-00

13-00444-00
13-01808-00
13-02466-00
10-00042-00

Typ.

13 15 12

LK02-3A

Figure 28.

LK02 Keyboard Module (Etch Rev. F)

840

IPB-LK02

~DmDDmD\
LlS~1
PARTS

For Shift LOCk}13
Key Only

15
16

1
2

LK02-04

F·Igure 3. 63 Keyswitch Array

8-41

IPB-LK02

FIG
&
ITEM
NO.
31
2
3
4
5
6
7

8
9
10
11
12
13
14
15
16

DESCRIPTION

ECO
CUT·IN

DEC
70-09892
PART NO.
00000

63 KEYSWITCH ARRAY

70-09892-00

*HOUSING ASSEMBLY
* *Housing, Keyswitch
**Contact, Solid
* *Contact, Quadfurcated
* Adapter, Key Cap
*Plunger
*Spring, Compression
*Retainer, Equalizer Bar
*SPACE BAR ASSEMBLY
**Space Bar
**Bracket, Equalizer Bar
**Bar, Equalizer
*Wire, Cam Follower (For Shift Lock Only)
*Wire, Pin Lock (For Shift Lock Only)
*Plunger, Shift Lock (For Shift Lock Only)
*Spring, Compression (For Shift Lock and Space
Bar only

70-10035-00
12-11859-00
12-11866-00
12-11865-00
12-11860-00
12-11862-00
12-11863-01
12-11861-00
70-09939-00
12-11857-00
12-11864-00
12-11858-00
12-12006-00
12-12007-00
12-12005-00
12-11863-03

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
2

DEC

IPB-LK02

842

DEC-LK03-IPB-l

ILLUSTRATED
PARTS
BREAKDOWN

LK03
KEYBOARD

HOW TO USE THE IPS
GENERAL
This IPS is compiled following the organization and nomenclature of
the engineering drawing structure.
MAJOR ASSEMBL Y LOCATOR
The Major Assembly Locator (first illustration) is an index that
provides a description and a figure reference for all illustrations used in
this manual.
INDENTED PARTS LIST
This manual identifies each assembly being broken down (figure
reference callout), and all parts of that assembly. Further breakdown
of an assembly is shown by an asterisk (0) preceding the item call outs
in the Description Column. The number of asterisks preceding an item
is used to denote the subordination of that item with respect to the
Major Assembly. A single asterisk preceding an item description
indicates that the item is part of the major assembly being illustrated.
Items that are subordinate to single asterisks items, are denoted by
two asterisks (00) and immediately follow the related single asterisk
item. Additional asterisks are used, as required, to denote further
subordination. This system of part identification, provides a means for
the user to identify the next higher assembly item and make alternate
selections for parts when the required replacement part or assembly is
not immediately available.
COLUMN CALLOUT DESCRIPTION
Figure & Item part.

I ndicates the figure number and item number of each

ECO Cut-In - The notation at the top of this column indicates the
ECO level of the system (option), at which the IPS was initially
prepared. Subsequent ECO level designations, that modify existing
parts or add new parts to the device, are inserted in the ECO Cut-I n
column next to the part that is added or modified. A bracket ([)
preceding the item description is used to indicate the parts affected by
ECO's.
Vendor Code/Part No. - I ndicates vendor parts that are not stocked
by DEC. Refer to the Field Service Spares Catalog (vendor part
number to DEC part number) for the vendor code cross-reference.
Used On Code - Letters in this column correspond to the variation
codes assigned in Figure 1. Parts with an Alpha notation(s) are used
only in those option variations. A blank indicates that the part is used
on all option variations.
Ref Fig No. - A cross reference between illustrations. For each Major
Assembly. the number in this column denotes the figure of the next
higher assembly. For all subassemblies, the number in this column
denotes the figure showing additional detailed breakdown.
SYMBOL USAGE
Hardware Designators - Alpha designators for screws (5), washers
(W), nuts (N), and retaining rings (R) are inserted after the item
number callouts on the illustration when stacked item numbers are
used.
Attaching Hardware - The @ symbol is inserted before any part that
is used as attaching hardware. Attaching hardware is denoted as those
parts that are not an integral part of the referenced assembly.

Description - Lists the name of the part and pertinent specifications
(when required). Asterisks preceding the description denote the
subordination of the part to the next higher assembly.

(NFR) Not Field Repairable - The (N F R) symbol is inserted after
any assembly that is not to be field dismantled.

DEC Part No. - Lists the DEC part ordering number. A blank in this
column indicates a DEC part number was not assigned at the time of
publication.

Other Symbols - Any other symbols that are required for kits,
accessories, etc., will be explained and appear as part of the item
description.

REVISION HISTORY
ECO LEVEL

PRINTING

1st Printing

LK03

54-10819
70-09891

00000 - 00000
00001 - 00001
00000 - 00000

DATE

12-2-74

PAGES AFFECTED

N/A

DEC reserves the right, without notice, to make substitutions and
modifications in the specifications of products documented in this
manual and further reserves the right to withdraw any of these
products from the market without notice.

Printed in U.S.A.

8-45

LK03 KEYBOARD ASSEMBLY

Fig. 1

KEYSWITCH ARRAY MODULE

Fig. 2

KEYSWITCH ARRAY ASSEMBLY

Fig. 3

LK03-01

Major Assembly Locator, L K03 Keyboard

8-46

IPB-LK03

FIG
&
ITEM
NO.
11
2
3
4
5
6
7
8
9
10
11
12
13

ECO
CUT-IN
DEC
PART NO_

DESCRIPTION
LK03 KEYBOARD ASSEMBLY

LK03-00

"KEYSWITCH ARRAY MODULE
"KEY CAP, SINGLE Complete Set (Includes
Caps Item 3 thru Item 13)
•• Key Cap, Single 0
•• Key Cap, Single 1
". Key Cap, Single 2
""Key Cap, Single 3
•• Key Cap. Single 4
"" Key Cap, Single 5
" "Key Cap, Single 6
" "Key Cap, Single 7
"" Key Cap, Single 8
"" Key Cap, Single 9
"" Key Cap, Single.

54-10819-00
90-09570-74

LK03
00000

VENDOR
USED ON
CODE

CODE

PART NO.

REF
FIG
NO.

90-09570-63
90-09570-64
90-09570-65
90-09570-66
90-09570-67
90-09570-68
90-09570-69
90-09570-70
90-09570-71
90-09570-72
90-09570-73

2
thru
13

LK03-02

Figure 1.

LK03 Keyboard Assembly

8-47

IPB-LK03

FIG

ECO
CUT·IN

&
ITEM
NO.

DESCRIPTION

1
2
3
4

DEC
PART NO.

54-10819
00001

VENDOR
USED ON
CODE

CODE

PART NO.

REF
FIG
NO.

KEYSWITCH ARRAY MODULE
(ETCH REV. 8)

54-10819-00

'Board, Etched Circuit
'Diode (01 thru 011) 0664
'Socket (J1) 16 Pin
'KEYSWITCH ARRAY

50-10818-00
11-00114-00
12-10025-00
70-09891-00

r---;:::::=::::====:L
L /
1-----(\
o DDca@[2@[2@
~cge]~C90 -------- 0

00151515 ~2

o ~15t;3t;3 ~
I

ETCH REV. B

LK03-03

Figure 2.

IPB-LK03

Kevswitch Arrav Module (Etch Rev. B)

8-48

FIG

ECO
CUT-IN

&
ITEM
NO.
31
2
3
4
5
6
7

DEC
PART NO.

DESCRIPTION
KEYSWITCH ARRAY ASSEMBLY

70-09891 -00

'HOUSING ASSEMBLY

70-10033-00
12-11859-01
12-11866-00
12-11865-00
12-11862-00
12-11860-00
12-11863-01

'" '" Housing, Keyswitch

"Contact, Solid
•• Contact, Quadfurcated
' Plunger
'AdaPter, Key Cap
'Spring, Compression

70-09891
00000

VENDOR
USED ON
CODE

CODE

PART NO.·

REF
FIG
NO.
2

-DEC

'----t
\

4
LK03-04

Figure 3.

Keyswitch Array Assembly

8-49

IPB-LK03

EK-LK03A-IP-OOl

ILLUSTRATED
PARTS
BREAKDOWN

LK03A
KEYBOARD

HOW TO USE THE IPB
GENERAL
This IPB is compiled following the organization and nomenclature
of the engineering drawing structure.
MAJOR ASSEMBLY LOCATOR
The Major Assembly Locator (first illustration) is an index that
provides a description and a figure reference for all illustrations used
in this manual.
INDENTED PARTS LIST
This manual identifies each assembly being broken down (figure
reference calloutl, and all parts of that assembly. Further
breakdown of an assembly is shown by an asterisk (*) preceding the
item callouts in the Description Column. The number of asterisks
preceding an item is used to denote the subordination of that item
with respect to the Major Assembly. A single asterisk preceding an
item description indicates that the item is part of the major
assembly being illustrated. Items that are subordinate to single
asterisks items, are denoted by two asterisks (* *) and immediately
follow the related single asterisk item. Additional asterisks are used,
as required, to denote further subordination. This system of part
identification, provides a means for the user to identify the next
higher assembly item and make alternate selections for parts when
the required replacement part or assembly is not immediately
available.
COLUMN CALLOUT DESCRIPTION
Figure & Item - I ndicates the figure number and item number of
each part.

Description Lists the name of the part and pertinent
specifications (when required). Asterisks preceding the description
denote the subordination of the part to the next higher assembly.

(NFR) Not Field Repairable - The (NFR) symbol is inserted after
any assembly that is not to be field dismantled.

DEC Part No. - Lists the DEC part ordering number. A blank in
this column indicates a DEC part number was not assigned at the
time of publication.

Other Symbols - Any other symbols that are required for kits,
accessories, etc., will be explained and appear as part of the item
description.

REVISION HISTORY
PRINTING
1st Printing

ECO LEVEL
LK03A
54-11635
70-09891

00000 . 00000
00000 - 00000
00000 - 00000

DATE
1-30-76

PAGES AFFECTED
N/A

Copyright © 1976 by Digital Equipment Corporation
DEC reserves the right, without notice, to make substitutions and
modifications in the specifications of products documented in this
manual and further reserves the right to withdraw any of these
products from the market without notice.

8-51

KEYSWITCH ARRAY MODULE
FIG.2

11 KEYSWITCH ARRAY ASSEMBLY

LK03A KEYBOARD ASSEMBLY
FIG.l

LK03A-01

Major Assembly Locator

8-52

IPB-LK03A

FIG
&
ITEM
NO.
11
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

JO
DEC
PART NO.

DESCRIPTION
LK03A KEYBOARD ASSEMBLY

LK03A

*KEYSWITCH ARRAY MODULE (14 KEY)
"KEYCAP SET
**Key-Cap. Single 0
**Key-Cap. Single 1
"*Key-Cap. Single 2
**Key-Cap. Single 3
"*Key-Cap. Single 4
**Key-Cap. Single 5
**Key-Cap. Single 6
"*Key-Cap. Single 7
**Key-Cap. Single 8
**Key-Cap. Single 9
*"Key-Cap. Single. (Decimal Point)
""Key-Cap. ENTER
"*Key-Cap. Single*"Key-Cap. Single.

54-11635-00
12-12287-74
12-12287-63
12-12287·64
12-12287-65
12-12287-66
12-12287 -67
12-12287-68
12-12287-69
12-12287-70
12-12287-71
12-12287-72
12-12287-73
12-12287 -01
12-12287-E2
12-12287-E4

ECO
CUT-IN
LK03A
00000

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.

LK03A-01

Figure 1.

LK03A Keyboard Assembly

8-53

IPB-LK03A

LK03A-02

F Igure
2.
"

",
Veyswitch Array Assembly

8·54

IPB-LK03A

FIG

&
ITEM
NO.
2-

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

IPB-LK03A

DESCRIPTION

DEC
PART NO.

KEYSWITCH ARRAY ASSEMBLY
(ETCH REV C)

54-11635-00

*Board, Etched Circuit
*Oiode (01-014) 0664
*Socket (J 1)
*11 KEYSWITCHARRAY
*SINGLE KEYSWITCH (KS1)
**Housing Assembly
* * - Housing, Keyswitch
**-Contact, Solid
* - *Contact, Ouadfurcated
**Spring, Compression
*-Plunger
* * Adapter, Key-Cap Straight
*SINGLE KEYSWITCH (KS2, KS3)
*-Housing Assembly
- * * Housing, Keyswitch
--*Contact, Solid
* * *Contact, Ouadfurcated
**Spring, Compression
-*Plunger
** Adapter, Tilted

50-11634-00
11-00114-00
12-11813-00
70-09891-00
70-11111-01
70-11110-00
12-11859-04
12-11866-00
12-11865-00
12-11863-01
12-11862-00
12-12677-00
70-11111-00
70-11110-00
12-11859-04
12-11866-00
12-11865-00
12-11863-01
12-11862-00
12-11860-00

8-55

ECO
CUT-IN
54-11635
00000

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
1

FIG
&
ITEM
NO.
31
2
3
4
5
6
7

DEC
PART NO_

DESCRIPTION
11 KEYSWITCH ARRAY ASSEMBLY

70-09891-00

*Housing Assembly
**Housing, Keyswitch
**Contact, Solid
**Contact, Quadfurcated
*Spring Compression
*Adapter, Key-Cap
*Plunger

70-10033-00
12-11859-00
12-11866-00
12-11865-00
12-11863-01
12-11860-00
12-11862-00

ECO
CUT-IN
70-09891
00000

VENDOR
USED ON
CODE

CODE

REF
FIG
PART NO. NO.
2

DEc

LK03A-03

Figure 3.

11 Keyswitch Array Assembly

8-56

IPB-LK03A

ECCENTRIC
W/CLUTCH
RIBBON DRIVE
SHAFT

8-32

RIBBON DRIVE

FAFNIR
BEARING

4-40
SETSCREW

8-32
SCREW

REAR BEARING

BACKSTOP
SPRING
7393-3

Figure 646 Fafnir Bearing Removal

6-91

APPENDIX A
REFERENCE DATA

A.I ABBREVIATIONS
The abbreviations used in this manual are listed in Table A-I.
A.2 SIGNAL GLOSSARY
The signal names used in this manual are listed in Table A-2.
A.3 IC PIN LOCATION DRAWINGS

The pin locations of the Integrated Circuits used in the LA36 are illustrated in Figures A-I through A-29.

A-I

Table A-I
Glossary of Abbreviations
2SB

Two Stop Bits

AKO
AMP
AR

Any Key On
Amplifier
Address Register

BCD
BEL
BS
BUF
BUFF

Binary Coded Decimal
Bell
Backspace
Buffer
Buffer

C/B

Carry/Borrow
Character Buffer Read Access Memory
Character Buffer Address
Character Generator Read Only Memory
Character
Clock
Clear
Centimeter
Counter
Column
Column High
Column Low
Control Read Access Memory
Control Read Access Memory
Control

CBRAM
CBA
CGROM
CHAR
CLK
CLR
CM
CNTR
COL
COL HI
COLLO
CONTROL RAM
CRAM
CTRL

DM
DRVR

Digital to Analog
Digital to Analog
Decoder
Direction
Down
Driver

ENB
ER

Enable
Error

F/F
FIFO

Flip Flop
First In/First Out

H
HDE

High
Head Drive Enable

INC
INIT
IPS

Increment
Initialize
Inches Per Second

D/A
DAC
DEC

DIR

A-3

Table A-I (Cont)
Glossary of Abbreviations

KBD
KBH
kHz

Keyboard
Keyboard Hold
Kilohertz

L
LCV
LF
18B

Low

M
MHz
mm
MPC
ms
MSB
MUX

Meter
Megahertz
Millimeter
Microprogrammed Controller
Microseconds
Milliseconds
Most Significant Bit
Multiplexer

NB
ns

Number Of Bits
Nanoseconds

POSHI
POSLO
POSMD
POS
POSIT
PT

Position High
Position Low
Position Middle
Position
Position
PRINT Timer

Read or Register
Read Acce~s Memory
Receive

p.s

RAM

Last Character Visibility
Line Feed
Least Significant Bit

RCV
RCVR
RDADR
RD
RD
REG
ROM

Read Address
Read or Register
Receive Data
Register
Read Only Memory

ST
SYNC

Status
Synchronize

TACH
TTL

Tachometer
Transitor To Transistor Logic

UART

Universal Asynchronous Receiver Transmitter

VREF

Voltage Reference

R~ceiver

A-4

Table A-I (Cont)
Glossary of Abbreviations
WC
WDCNT
WTADR

Word Count
Word Count
Write Address

Read Access Memory Transmit Data
Transmit

XMIT

A-5

Table A-2
Signal Glossary
Mnemonic

Definition

Source

Destination

BELL SINK

Bell Return

JS-2

Speaker

BELL SOURCE

+5 V to Bell

R118

JS-I, Speaker

COMMON

From LF Motor

JS-4

LF Motor

PHASE I

To LF Motor

JS-7

LF Motor

PHASE 2

To LF Motor

JS-6

LF Motor

SOL 1:7

Solenoid Driver Outputs to Head
Solenoids

MPC3 BMBOO

Buffered Memory Bit 0

ES84 or E614

E49-9, E21-2
E31-IS, E 15 -15

MPC3 BMB01

Buffered Memory Bit I

ES8-S or E61-S

E49-S, E21-S
E31-14, EIS-14

MPC3 BMB02

Buffered Memory Bit 2

ES8-6 or E61-6

E49-3, E21-8
E31-13, EIS-13

MPC3 BMB03

Buffered Memory Bit 3

ES8-7 or E61-7

E49-I,E21-11
E31-11, E 15 -II

MPC3 BMB04

Buffered Memory Bit 4

ES8-8 or E61-8

ES4-13, E46-23
ESO-1S

MPC3 BMBOS

Buffered Memory Bit 5

ES8-9 or E61-9

ES4-11, E46-22
ESO-14

MPC3 BMB66

Buffered Memory Bit 6

ES8-100r
E61-10

ES4-9, ES3-1
E46-21, ESO-13

MPC3 BMB07

Buffered Memory Bit 7

ES8-11 or
E61·II

ES4-S, ES3·2
E46-20

MPC3 MBOO

Memory Bit 00

ES84 or E614

MPC3 MBOI

Memory Bit 01

ES8-S or E61-S

MPC3 MB02

Memory Bit 02

ES8-6 or E61-6

MPC3 MB03

Memory Bit 03

ES8·7 or E61-7

MPC3 MB04

Memory Bit 04

ES8-8 or E61-8

MPC3 MBOS

Memory Bit 05

ES8-9 or E61-9

A-7

Table A-2 (Cont)
Signal Glossary
Mnemonic

Definition

Source

Destination

MPC3 MB06

Memory Bit 06

E58-10 or
E61-10

MPC3 MB07

Memory Bit 07

E58-11 or
E61-11

MPC4CLRBEL

Clear Bell

E44-9

E36-3

MPC4 CLRC/B

Clear Carries or Borrows

E44-16

El1-13

MPC4CLRDA

Clear Data Available

E44-2

E60-11

MPC4CLRHDE

Clear Head Drive Enable

E44-13

E39-11 , E30-11

MPC4 CLR INIT

Clear Initialize

E44-17

E51-1

MPC4CLRKBH

Clear Keyboard Hold

E44-1

E51-10

MPC4 CLR568

Clear 568

E44-6

EI5-23, E31-4
E30-4

MPC4 CSOO

Clocked Selector 04

E46-1

E42-1

MPC4CSOl

Clocked Selector 04

E46-2

E42-2

MPC4 CS02

Clocked Selector 04

E46-3

E42-l3

MPC4 CS03

Clocked Selector 04

E46-4

E37-4

MPC4 CS04

Clocked Selector 04

E46-5

E37-5

MPC4 CSI0

Clocked Selector 04

E46-9

MPC4CSII

Clocked Selector 04

E46-10

E27-3

MPC4 CS12

Clocked Selector 04

E46-11

E44-18,19

MPC4 CS13

Clocked Selector 04

E46-13

E44-18,19

MPC4 CS14

Clocked Selector 04

E46-14

E42-5

MPC4 CS15

Clocked Selector 04

E46-15

E37-1, E42-3

MPC4 CS16

Clocked Selector 04

E46-16

E37-2, E37-13
E42-4

MPC4 CS17

Clocked Selector 04

E46-17

E53-4

Table A·2 (Cont)
Signal Glossary
Mnemonic

Definition

MPC4 LOAD CBA

Load Character Buffer Address

E444

ES2·9

MPC4 LOAD D/ A

Load Digital/Analog

E44·10

E14·9

MPC4MAX

Maximum

E23-6

E31·S, E144, S,
12, 13

MPC4 REGO:3

E32·2, 3, 6, 7

ES24, S, 12, 13
E38-1,S,9,1O

MPC4 SOOO

Selector 0

ESO-1

E22-2

MPC4 SOOl

Selector 1

ESO-2

E27-2

MPC4 S002

Selector 2

ESO-3

E21·3

MPC4S003

Selector 3

ES04

E31-9

MPC4S004

Selector 4

ESO-S

E1S-9

MPC4SETBEL

Set Bell

E44·9

E364

MPC4SETHDE

Set Head Drive Enable

E44-11

E39-10

MPC4 SET HOLD

Set Hold

E44-1S

E404

MPC4 STEP LF

Step Line Feed

E44-14

E24-3, 11, E29-S

MPC4 SKIP

Skip

E40-11

E60-2

MPC4 WRITE BUF

Write Buffer

E44-S

E60·10, ES6-3

MPC4ZERO

Zero

E23-8

E18-13, E31-3, 6

MPC4 -1 REG

Decrement Register

E44-7

E324

MPC4+1 REG

Increment Register

E44-3

E32-S

MPCS CLK

Clock

E64-S, 12

E46-18,19,
E29-1O,E49-13

MPC5 S.I.

Serial In

E66·6

ESS-20

MPC5 1.184 J,lS

1.184 J,lS

E13-12

E37-1O, E13-1,
E64-9, E7-13,
E9-3,11

MPC5 1.76 kHz

1.76 kHz

E68-11

E30-3, ES9-3

Source

A-9

Destination

Table A-2 (Cont)
Signal Glossary
Mnemonic

Definition

Source

Destination

MPC5 4.8 kHz

4.8 kHz

E63-II

E26-I4, EI74

MPC5 19

E26-9

E67-5, E31·21, 22

MPC5 76 ps

76 ps

E26-Il

E3-3, E5-3

MPC5208

208

E26-12

E40-1O, E67-II,
EI7-7,EI5-7,
E31-19

MPC5568

568

E30-5,6

E64-lO, E94, 10
E13-I4, E37-9

MPC5 592 ns

592 ns

EI7-13

E20-1

MPC6 BEL

Bell

E19-1

E15-6

MPC6 BS

Back Space

EI9-9

EI5-20

MPC6CR

Carriage Return

E19-3

E25-13, EI54

MPC6DA

Data Available

E55-19

E31-7

MPC6 HS1:7

Head Select

E28-4 to 11 and
E334 to 11

Head Solenoid
Drivers

MPC6HT

Horizontal Tab

EI9-7

E15-21

MPC6KBH

Keyboard Hold

E51-8

E31-20

MPC6 LF

Line Feed

E19-6

E25-1, E15-5

MPC6PNTABL

Printable

E33-11

E25-11, E31-1

MPC6 S.O.

Serial Out

E55-25

E29-12

MPC7 BORROW

Borrow

E12-3

EI2-1,EI5-22
E31-18

MPC7 CARRY

Carry

E7-6

E31-23

MPC7 COL INC
COUNT 0:2

Column Increment Count

EI6-2, 3, 6

E28-19 to 21,
E33-19 to 21

MPC7 INC

Increment

E30-9

E15-3

MPC7 PT COM +5 V

Print Timer Common

11-U,V

11-13,17
(Rl, R2)

A-lO

Table A-2 (Cont)
Signal Glossary
Mnemonic

Source

Definition

Destination

MPC7SUM

Sum

E1-6 (11-B)

MPC8 BEL

Bell

R58

11-TT,11-38

MPC8 HDE (HDEM)

Head Drive Enable

E39-8

15-2

MPC8INIT

Initialize

E51-5,6

E11-2, E31-8

MPC8 LF1

Line Feed 1

E24-9

11-11

MPC8 LF2

Line Feed 2

E24-5

11-P

MPC8 LF HOLD

Line Feed Hold

E29-6

Jl-HH

MPC8 W.U.

Wake Up

Q9-C

E53-5, E10-12,
E36-1,11-DD,
E14-1

P.T.COLL 1

Print Timer Collector 1

QI-C (11-21)

Jl-Y (E34-2)

P.T. CaLL 2

Print Timer Collector 2

Q2-C (11-25)

11-CC (E35-2)

A-II

Vee

GND

IC~0013

Figure A-I 380 Quad 2-Input NOR Gate

PIN CONFIGURATION
24

VOO

Vee

*OATA OUT 1

4(LSB)

*OATA OUT 2

*OATA OUT 3

*OATA OUT 4

*OATA OUT 5

*OATA OUT S

VGG

*OATA OUT 7

VBB

*OATA OUT 8

I1(M.B)

PROGRAM

Vee

*THIS PIN IS THE OATA INPUT OURING PROGRAMMING

Figure A-2 I702A 8-Bit Reprogrammable ROM

A-13

PACKAGE "A" -

BENT LEADS

Index Mar

INDEX MARK
OR
-""""11::"--....

Vss

NOTCH
IC-0123

CS1

esO

PACKAGE "B" - BRAZED LEADS

°1
°2

°3

Note

°4

A2
A3

°5

°7Vnn

°6

Ao
Al

AS
IC-0120

IC-0124

Figure A-3 2627P A6-01 Character Generator Alpha (Sheet 1 of 2)

A-14

FUNCTIONAL BLOCK DIAGRAM
11

CHIP SELECT

o 7 0 6 0 5 0 4 0 3 02 0 1 0 0

TRI-STATE
OUTPUT STAGES

'----_eiJ
2

23
512 X 8

ROM

NOTE: Choice of connection A or B for each chip select
is available as a mask option.

13 14 15 16 17 18 19 20 21

IC-0121

Figure A-3 2627P A6-01 Character Generator Alpha (Sheet 2 of 2)

SCHEMATIC
TOP VIEW
FREQUENCY
COMPENSATION
INVERTING
INPUT

NON-INVERTING
INPUT

OUTPUT

PIN LOCATOR
le-0106

Figure A-4 3101 Random Access Memory

A-IS

A PACKAGE
14 13 12 11

10 9

PACKAGE

VAC

14
13

Ie-0022

Figure A-5 7400 Quad 2-Input Positive NAND Gate

Vee..

4 y 4B

'l-A

3'(

3.8

2. 'f

<.f> GNP

lC-0129

Figure A-6 7401 NAND Gate-Quad 2-Pin Open Collector

GND

POSITIVE LOGIC: y. Ii
IC-OOII

Figure A-7 7404 Hex Inverter

A-16

Vee

GND

POSITIVE LOGIC: Y·AB

Figure A-8 7408 Quad 2-Input Positive AND Gate

Vee

GND

POSITIVE LOGIC: y. ABC

Figure A-9 7410 Triple 3-Input Positive NAND Gate

A-17

BINARY SELECT

r - - - - - - - ' - - - - - - " OUTPUT
A

GNO

POSITIVE LOGIC: y. ABCO
Ie-0008

OUTPUTS

Ie-0009

Figure A·lO 7413 Schmidt Trigger

POSITIVE

GNO

LOGIC: y. Ali

Figure A·ll 7416 Hex Inverter Buffer/Driver

A·I8

Vee

GND

POSITIVE

LOGIC: YoA

.---_--.-_ _._---<>vcc
3K.o.

OUTPUT Y

INPUT A

L-----~-~-+_-oGND

Component

values shown ore nominal.
le-C05S

Figure A-12 7417 Hex Buffers/Drivers

Vc.c

0.710 MAX---J

i~@@@~~~1

i:::::1
t*Nl>
IC-0128
IC-0130

Figure A-13 7420 NAND Gate-Dua14-Input

A-19

No Package Drawing Available

Figure A-14 7423

Vee

GND

IC-0126

Figure A-IS 7437 NAND Gate-Quad 2 In Buffer, 14 Pin

A-20

INPUTS

OUTPUTS

ABC

0123456789

~\---------O-U--TPUTS

GND

lC-0164

INPUT A

INPUT B
OUTPUT 3

A
B
C

OUTPUT 4

ii
A

B
C

OUTPUT 5

ii
A

INPUT C

OUTPUT 6

ii
A
B

OUTPUT 7

INPUT 0

OUTPUT 8

o
Vee' PIN 16
GNO'PIN 8

OUTPUT 9

Ie-aOIS

Figure A-16 7442 4-Une-to-IO-Une Decoders

A-21

Vee

GND

PIN LOCATOR
(TOP VIEW OF IC)
IC~OOOl

Figure A-I7 7474 Dual D-Type Edge-Triggered Flip-Flop

DATA SENSE DATA SENSE
I NPUT OUTPUT I N PUT OUTPUT

SELECT ,INPUTS

BCD

SELECT MEM WRITE
DATA SENSE DATA SENSE
INPUT •
•
' INPUT OUTPUT INPUT OUTPUT
A
ENABLES
1
1
2
2

Ie-0007

Figure A-I8 7489 64·Bit Read/Write Memory

4
5
PIN LOCATOR
(TOP VIEW OF IC)
3

le-Ol00

Figure A·I9 7493A Counter Asynch Up, Binary

A·22

Vee

1
CLEAR

CLEAR

2 Rexll GND

Cext

FUNCTIONAL LOGIC / PIN LOCATOR

Figure A-20 74123 Monostable Multivibrator

DUAL-IN-L1NE PACKAGE

(TOP VIEW)

DATA INPUTS
r---------~A~--

Vee

DATA SELECT

________~~
13

7
\

Y
DATA INPUTS

o STROBE W

D
GND
OUT DATA
PUT SELECT

POSITIVE LOGIC

W=SIC~BCDEO + ABCDE, + "BCDE2 + ABCDE 3 ... ABCDE4 +ABCDE 5 + "BCDE6 + ABCDE 7
+ABCDEs +ABCDE 9 +ABCDElO+ABCDEI1 + ABCDEI2+ABCDEI3+ABCDE,4 + ABCDE, 5)
IC-Ol17

Figure A-21 74150 Data Selector/Multiplexer

A-23

DUAL-iN-LINE PACKAGE (TOP VIEW)
OUTPUTS

INPUTS

~----------------~yr------------------J
OUTPUTS
IC-0044

Figure A-22 74154 4-Une-to-26-Une Decoder/Demultiplexer

No Package Drawing Available

Figure A-23 74161 4-Bit Binary Counter

A-24

Vec

CLEAR 10

115

CLOCK

GND
IC-0167

TRUTH TABLE
INPUT
In

OUTPUTS
'n+ 1

H
L

L
H

to:: Bit time before
clock pulse.
tn"'1:: Bit time after
clock pulse.

(4)

t--+--aCLK OB (6)
CLEAR

",(",I2:':)+-l--l DC

Oc (10)

+--+-aCLK Oc (11)
CLEAR

.,:(-,,13:':)+-l--lDD
CLOCK

(15)

~--_-t---j~CLK QD (14)
CLEAR

r -....._ /

CLEAR
Pin (16)= VCC, Pin (B)=GND
IC-OOtS

Figure A-24 74175 Quad D-Type Flip-Flop with Clear

A-25

INPUTS
,----.

INPUTS
OUTPUT ,_ _ _...._ _--.

OATA
RIPPLE
A
COUNT COUNT

MAX/
MIN
LOAD

DATA

GNO

MIN

DATA

ENABLE DOWN

'-v-I ' - . , - - I ' - r - - ' '-v--'
INPUT

OUTPUTS

INPUTS

OUTPUTS

IC-0127

.093 ~--__-+---t'"-r
Nt>Pl
t:J ./~o ----+--~
}.j()fY/

0®@@@®0@
IC-0131

Figure A-25 74190 Counter, Synch Up/Down Decade, 16 Pin

A-26

"'\.

CARRY
OUTPUT

J
DATA
INPUT A

BORROW
OUTPUT

r-'"

PRESET
QA

DOWN
COUNT

OUTPUT QA

-T
UP
COUNT

D
DATA
INPUT B

rL----'-

~
DATA
INPUT C

CLEAR

PRESET
Oe

OUTPUT Qe

,. T
0B

[L-I-

:gp
DATA
INPUT 0

~EQR

PRESET
QC

OUTPUT Qc

r-LJ

r--fJ-

---''-PRESET
QO

...,

OUTPUT 00

----rLOAD

Oil f-

--*
IC-OOOl

Figure A-26 74193 Synchronous 4-Bit Up/Down Counter (Sheet 1 of 2)

A-27

INPUTS

OUTPUTS
~
DATA CLEAR ~ LOAD
DATA
A
BORROW CARRY
D

LOAD

DATA

COUNT COUNT

IN~UT '---,---'~ ~
OUTPUTS

INPUTS

GND

OUTPUTS

LOGIC' LOW INPUT TO LOAD SETS
QAoA, QBoB, QCC, AND QDoD

le-Ol01

Figure A-26 74193 Synchronous 4-Bit Up/Down Counter (Sheet 2 of 2)

TOP VIEW

IC-0119

Figure A-27 Universal Asynchronous Receiver Transmitter
/1/1U1 - D)?
('bU/lL

II'U

UIU£)

B,I1LA/lY'£/
(lO/??PEIV S',q7"/0IV
//lJ I/CRTl1U6

//l.JPUT
/uO/U-J/V//,cRTlIUG
//lJPUr

OUTPUT

vIC-0122

Figure A-28 301 AN DIP Operational Amplifier

A-28

(i)

TERMINAL CONNECTIONS
PIN I • INPUT
PIN 2' OUTPUT
CASE' GROUN 0
Ie - 0168

Figure A-29 309 K Regulator

A-29

INDEX
Abbreviations, A-I
Attaching hardware, 8-2

IC pin location drawings, A-I
Idler gear, 6-47
Idler gear assembly, 6-17
Illustrated Parts Breakdown, 8-1
Indented Parts List, 8-1
Initialization routine (INIT), 4-5
Input routine, 4-11
Installation procedure, 2-2

Backstop spring, 6-40
Bell operation, 1-4
Bell routine, 4-12
Bell system, 4-42
Bell test, 5-4
Bell volume, 1-4,2-3
Carriage alignment, tool setup, 6-48
Carriage assembly, 6-11
Carriage, plain bushing, 6-32
Carriage servo system, 1-9, 4-37
Carriage shaft, 6-28
Carriage subsystem, 4-47
Cautions, 3-10
Changing ribbon, 3-7
Character buffer/generator and print head system, 4-33
Character printing, 1-4
Checkout and acceptance procedures, 2-4
Clock logic, 4-28
Clock test, 5-5
Column callout description, 8-1
Column increment counter and carry/borrow generator, 4-40
Control logic, 4-19
Cover spring clips, 6-48
Current loop, 1-10,2-3
Current loop interface, 5-5
Data communications interface, 4-28
DC motor and encoder assembly, 6-7
Disassembly, assembly and adjustment procedures, 6-22
ECO cut in, 8-1
EIA/CCITT interface, 1-12
Electrical servicing, 5-1
Electrical tests, 5-1
Encoder and threshold detector, 4-40
Encoder signal detector, 4-40
Encoder signal processing test, 5-1
Engineering drawings, 7-1
Fan, 6-20
Hardware designators, 8-2
How-To-Use-The-IPB,8-1

Keyboard system, 4-22
LCV routine, 4-16
LF stepping test, 5-4
Line Feed routine, 4-13
Line Feed stepper system, 4-45
Line filter assembly, 6-22
LK02 keyboard, 8-33
LK02 keyboard assembly, 6-4
LK03 keyboard, 8-41
LK03 keyboard assembly, 6-4
Loading paper, 3-3
Logic board assembly, (M7722), 6-19
Major assembly locator, 8-1
Mechanical servicing, 6-1
Next routine, 4-16
Off line tests, 5-1
On line tests, 5-5
Operating procedures, 3-3
Operations, 3-1
Operator controls, 3-1
Optional features and accessories, 1-12
Optional half-duplex, (active or passive) current loop
interface, 1-11
Paper feed subsystem, 4-50
Paper feeding, 1-4
Parity setting, 2-3
Peripheral interface port, 1-12
Physical characteristics, 1-1
Position routine (POSIT), 4-8
Power board assembly, 6-20
Power supply, 1-9
Print bar, 6-22

INDEX-1

INDEX (Cont)
Print head assembly, 6-1
Print routine, 4-13
Printable character test, 5-4
Printer mechanism, 4-45
Printer mechanism assembly, 6-5
Program description, 4-1
Power supply and regulator, 4-45
Rear door bushing, 6-47
Removal, replacement, and adjustment procedures, 6-1
Ribbon chassis assembly, 6-15
Ribbon drive assembly, 6-9
Ribbon drive fafnir bearing, 6-37
Ribbon drive pulley, 6-36
Ribbon drive rear bearing, 6-42
Ribbon drive system, 1-9
Ribbon eccentric with clutch, 6-38
Ribbon feed subsystem, 4-49
Ribbon spool friction disks, 6-44
Ribbon spool ratchet wheel, 6-45
Scratch pad memory, 4-3
Serial line interface, 5-6
Servo routine, 4-8
Servo speed test, 5-4
Signal glossary, A-I
Site considerations, 2-1

Speed routine, 4-10
Standard current loop interface, 1-10
Stepping motor assembly, 6-18
Symbol usage, 8-2
System configuration, 2-1
Tachometer, summing network and sum amplifier, 4-39
Technical characteristics, 1-12
Timing, 4-19
Timing belt, 6-3
Tractor assembly, 6-17
Tractor drive gear /line feed clutch, 6-36
Tractor drive shaft, 6-26
Tractor gap adjustment, 6-48
Tractbrsupport shaft, 6-27
Transformer, 6-21
Troubleshooting, 3-9
Troubleshooting charts, 5-7
Unpacking and inspection, 2-1
Universal aysnchronous receiver/transmitter (UART), 4-33
Upper and lower case character selection, 1-5
Used-on-Code, 8-2
Vendor code/part no., 8-1
Wake-up circuit, 4-45

INDEX-2

I
I
I
I
I
I
I
I

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