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DEC-12-HR2B-D

January 1972

135 pages

Original

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Document:	PDP-12 Maintenance Manual Volume 2 Installation and Maintenance
Order Number:	DEC-12-HR2B-D
Revision:	0
Pages:	135
Original Filename:	DEC-12-HR2B-D_PDP-12_Maintenance_Manual_Volume_2_Installation_and_Maintenance_Jun72.pdf

OCR Text

Digital Equipment Corporation
Maynard, Massachusetts

PDP-12
maintenance manual
volume II
installation and
' maintenance
/

I
laboratory data products

DEC-12-HR2B-D

PDP-12
maintenance manual
volume II
installation and
maintenance

digital equipment corporation · maynard. massachusetts

1st Printing January 1971
2nd Printing (Rev) September 1971
3rd Printing June 1972

The material in this manual is for information purposes and is subject to change with·
out notice.

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

PDP
FOCAL
COMPUTER LAB

CONTENTS

Page
CHAPTER 1 INSTALLATION
1.1

Planning

1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
1.1.6
1.1. 7
1.2
1.2. l
1.2.2
1.2.3
1.3
1.3.1

Site Considerations
Space Requirements
Floor Construction
System Layout
Fire and Safety Precautions
Installation Constraints
Environmental Considerations
System Configurations
Standard Configurations
System Expansion
1/0 Interface
Predelivery Preparation

1-1
1-1
1-1

1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.4
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
1.4.7
1.4.8
1.4.9
1.5
1.5.1
1.5.2
1.5.3
1.5.4
1.5.5

1-3
1-3
1-4
1-4
1-5
1-5
1-6
1-6
1-6
1-6
1-8
1-9
1-9
1-11

Preliminary Procedures
Shipping and Receiving Constraints
System Power Requirements
Source Power Requirements
Primary ac Power Cables
Service Outlets
Cabling
Unpacking, Installation and Inspection
General
Cabinet Unpacking

1-11

1-11
1-12
1-12
1-12
1-13

Cabinet Installation
Cabinet Inspection
Teletype Unpacking
Teletype Installation and Setup
Prewired Option Installation
Peripheral Equipment Inspection
Miscellaneous Items
Checkout
Preliminary Operating Checks
Teletype Test
Computer Memory Test
RIM Loader
Running MAINDECs

1-13
1-14
1-14
1-15
1-15

1-15
1-15
1-15
1-16
1-16

1-16
1-17

CHAPTER 2 MAINTENANCE
2.1
2.2
2.2.1

Introduction
Maintenance Equipment
Maintenance Test Programs

2-1
2-1

2.2.2
2.3

Mounting DIAL MAINTENANCE TAPES
Preventive Maintenance

2-3
2-3

2-2

iii

CONTENTS (Cont)
Page

2.3.1
2.4
2.4.1
2.4.2
2.5
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.5.6
2.5.7
2.5.8
2.5.9
2.5.10
2.5.11

Scheduled Maintenance
Corrective Maintenance
Preliminary Investigation
System Troubleshooting
Troubleshooting Techniques
Introduction
Console Checks
LINC-Mode Processing
8-Mode Processing
TCI 2 Tape Subprocessor
TC 12 Console Checks
Logic Troubleshooting
Module (Circuit) Troubleshooting
Repairs and Replacements
Validation Tests
Log Book Recording

2-4

2-5
2-6
2-6
2-6
2-6
2-7
2-8
2-9
2-9
2-10
2-12
2-12

2-13
2-14

2-14

CHAPTER 3 ADJUSTMENTS
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.2
3.2.1
3.2.2
3.3
3.3.1
3.4
3.5
3.5.1
3.5.2
3.5.3
3.5.4
3.5.5
3.5.6
3.6
3.6.1
3.6.2
3.6.3
3.7
3.7.1
3.7.2

Memory Current and Strobe
Initial Current Adjustments
Initial Strobe Adjustment
Memory Strobe Adjustments
Final Current Adjustments
Memory Margins and Final Strobe Adjustments
Power OK
Check Procedure
Adjustment Procedure
Extended Me~ory MCI 2
Set-up and Adjustment Procedure
Teletype Clock
LINCt ape
Tape Timing Pulses
LTD XTLK Delay
LTD TTOK Delay
LTD TAPE FAIL Delay
LTD ACIP Delay
Mark Clock Adjustment
TUSS Tape Transport
TU55 Brake Adjustment
TU55 Torque Adjustments
TU55 Transport Head Replacement and Adjustment Procedures
TU56 Tape Transport
TU56 Brake Adjustment
Oscillator Adjustment

3-1
3-1
3-2
3-2
3-4
3-6
3-6
3-6
3-6
3-7
3-7
3-8
3-9
3-9
3-11
3-12
3-13
3-14
3-16
3-17
3-18
3-19
3-21

3-24
3-24
3-26

CONTENTS (Cont)
Page

3.8
3.8.l
3.8.2
3.8.3
3.8.4
3.8.S
3.8.6
3.8.7
3.9
3.9.1
3.9.2

Analog (AD 12) and Display (VR 12,VCI 2)
Digital-to-Analog Adjustment Procedure (A6 l 5)
VR 12 Size and Position Adjustments
Brightness and Brightness Preset Adjustment
Deflection Amplifier Quiescent Current Adjustment (VR I 2)
Analog-to-Digital Adjustment Procedure
Sample and Hold Adjustment Procedure (A404)
External Analog Channel Adjustment Procedure
Extended Analog (AG 12,AM 12)
Set-up Procedure
Adjustment Procedure

3-26
3-27
3-29
3-29
3-30
3-30
3-32
3-32
3-33
3-33
3-34

CHAPTER 4 FIELD INSTALLATION AND
CHECKOUT OF PREWIRED OPTIONS
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.S

Unpacking
Installation
Installation of Panels and Cables
Unit and Cable Installation forTU55, VR12 orVR14
TUS6 Unit and Cable Installation
KF 12-B and DM 12 Installation
Checkout
Checkout of the DPl 2-B
Checkout of TC 12-F
Checkout of the LINCtape System
Checkout of VR 12 or VR 14
Checkout of the KF12-B and DM12

4-1
4-2
4-6
4-8
4-11
4-14
4-21
4-22
4-22
4-23
4-25
4-25

CHAPTER 5 TELETYPE MAINTENANCE MODELS ASR 33 AND 35
S. l
S.2
S.2.1
S.2.2
5.3
S.4

S-1
S-2
S-2
5-2
5-3
5-5

Equipment
Preventive Maintenance
Weekly Tasks
Preventive Maintenance Tasks
Corrective Maintenance
Teletype Parts

APPENDIX A MAINTENANCE AND SERVICE OPTIONS
A.I
A.I.I
A.1.2
A.2
A.3
A.4

Service Contracts
Service Contract Options
Eligibility for Service Contract Coverage
Per-Call Coverage
Depot Repair
Field Installation of Additional DEC Options

A-1
A-1
A-2
A-2
A-2
A-3

CONTENTS (Cont)

Page
APPENDIX B CUSTOMER ACCEPTANCE
B.l

Special Customer Requirements

B-1

B.2
B.3

Customer Programs
Special Customer Acceptance Testing

B-1
B-1

B.4

Diagnostics
System Software Acceptance

B-1
B-2

B.5

APPENDIX C FORMS AND CHECKLISTS
C.l

Customer Acceptance Forms

C-1

C.2

Customer Data Forms

C-1

C.3
C.4

Software Trouble Reports
DECUS Information

C-2
C-2

C.5
C.6
C.7
C.8

Basic Accessory Checklist

C-2

Optional Equipment Checklist

C-2

Software Checklist
Final Distribution of Forms

C-2
C-2

APPENDIX D SOFfWARE AND PREWIRED OPTION DIAGNOSTICS
ILLUSTRATIONS
Art No.

Page

Pedestal Flooring
Raceway Flooring

10-0479
10-0478

1-2
1-2

PDP-12 Expanded Equipment Layout

12-0255

1-7

Minimum PDP-12 Equipment Floor Plan Requirements
Packing Details

12-0256

1-7

1-5
1-6
2-1

Hubbell Wall Receptacle Connector Diagram
Integrated Circuit Location

09-0414
12-0133

2-13

2-2

Integrated Circuit Pin Location - Top View

12-0134

2-13

3-1

Ground Reference

3-2

MEM START and STROBE
Positive Memory Current
Negative Memory Current
Teletype Clock (Sweep at .5 ms)

3-4

LTT TPO/TP2 Pulse Duration

3-10
3-11
3-12
3-13
3-15
3-16

Figure No.
1-1
1-2
1-3

1-4

3-3
3-4
3-5
3-6
3-7
3-8
3-9

Title

3-10
3-11
3-12
3-13

LTT TP3/TP4 Pulse Duration
LTD XTLK Delay Time
LTDTTOK Delay
LTD Tape Fail Delay
LTD ACIP Delay
Mark Clock
TU55 Brake Adjustment

3-14

TU55 Torque Adjustment Tabs

1-8
1-10

3-5
3-5
3-9

12-0261

3-17

3-18

3-20

ILLUSTRATIONS (Cont)
Figure No.
3-15
3-16
3-17
3-18
3-19
3-20
3-21
3-22
4-1
4-2
4-3
4-4

4-5
4-6
4-7
4-8
4-9
5-1
5-2

Title

Art No.

TU55 Stop Delay Adjustment
Skew Checker Schematic Diagram
Skew Checker Output
80 ms Brake Delay Adjustment
25 ms Oscillator Adjustment
D/ A Line Display
Sample and Hold Adjustments
A-to-D Display
PDP-12 Equipment Layout
TU55 LINCtape Transport
VR12
TU55, VR12, or VR14 Mounting Assembly
TU56 LINCtape Transport
Front Assembly of TU56
Rear Plate Assembly of TU5 6
Top View of TU56 Rest Plate Assembly
DM 12 Cabling Diagram
Teletype Connections
Teletype Signal Waveform and Bit Relationship
for the Character "U"

12-0127
12-0126

12-0086

12-0260

12-0253
12-0258
12-0257
12-0254
12-0299
12-0088
81-00IO

Page
3-21
3-23
3-24
3-25
3-26
3-27
3-28
3-31
4-7
4-9
4-9
4-10
4-11
4-12
4-12
4-13
4-20
5-4
5-5

TABLES
Table No.
1-1
1-2
1-3
2-1
2-2
3-1
3-2
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
5-1
5-2
5-3
D-1

Title

Page

Standard PDP-12 Shipping Specifications
Hubbell Wall Receptacle Part Numbers
Power Cable Line Identification
Maintenance Equipment
Power Supply Specifications
Memory Diagnostics
Monitor Table for Channels 20 through 37
Prewired Options
Option MAINDECs Checklist
Option Modu!e and Cable List
Interconnections of TU55
DC Voltage Connections
TU56 Logic Cable Connections
Format Conversion Table
Format Conversion Table
YR 12 Controls
Teletype Maintenance Tools
Maintenance Programs
Spare Parts for Keyboard Model 33 ASR Teletype
Options Diagnostics

1-9
1-10
1-11
2-1
2-5
3-8
3-34
4-1
4-2
4-3
4-10
4-14
4-14
4-15
4-22
4-25
5-1
5-2
5-6
D-4

vii

FOREWORD

The PDP-12 Maintenance Manual, published in four separate volumes, is a guide for Field Service Engineers or
other personnel involved with the care and maintenance of the PDP-12 Computer. The Maintenance Manual is
organized as follows:
VOLUME I PRINCIPLES OF OPERATION

This volume contains a description of PDP-12 logic. An overall view of the system is presented in seven
chapters entitled Central Processor, Memory, Input/Output, Teletype, LINC Devices, Tape Processor,
and Prewired 1/0 Bus Options. The text describes logical relationships among the various elements of
the PDP-12.
VOLUME II INSTALLATION AND MAINTENANCE

The first chapters of this volume describe the unpacking, installation, and preliminary check-out procedures for the PDP-12. The remainder of the volume comprises procedures used in the day-to-day
maintenance, adjustment, and repair of the computer.
VOLUME III LOGIC SCHEMATICS

Volume III consists primarily of flow charts and block schematics that describe the PDP-12. The
block schematics, lists, and flow charts in Volume III are reduced ( 11 in. x 17 in.) versions of
engineering drawings.
VOLUME IV MODULE SCHEMATICS

The circuit schematics in Volume IV describe all the module types used in the PDP-12, including both
the regular production DEC modules and those design0d especially for the PDP-12.

WARNING
Maintenance procedures should be performed by qualified service personnel only.
High voltages are present within the equipment and are potentially dangerous. All safety precautions must be observed.
Inherent implosion protection is considered in the CRT design.
However, the tube may be damaged if it is subjected to rough
treatment or dropped while being removed from or installed
in the display. Caution, therefore, must be exercised during
these operations.

CHAPTER 1
INSTALLATION

This chapter presents planning, installation, and interface information for the PDP-12 and its options.
1.1 PLANNING
1.1.1 Site Considerations
Adequate site planning and preparation can simplify the installation process and result in an efficient, reliable
PDP-12 System installation. DEC Sales Engineers and/or Field Service personnel are available for counseling and
consultation with customer-designated personnel regarding the installation.
Site planning should include a list of the components to be used in the installation, such as: tape-storage cabinets,
Teletype® supplies, work tables and any other items pertinent to the user's computer applicatioo.
Primary planning considerations are: the availability and location of adequate power, and the existence of fire
protection. If the existing environmental conditions dictate, air-conditioning and/or humidifying equipment installation can become part of the site-planning program (see Paragraph 1.1. 7).
1.1.2 Space Requirements

Space requirements are determined by the specific system configuration to be installed and, when applicable, provision for future expansion. To determine the exact area required for a specific configuration, a floor plan layout
of the proposed computer room is helpful. When applicable, space must be provided for storage of tape reels,
printer forms, card files, etc.
In large installations where test equipment is maintained, DEC recommends that the test equipment storage area
be within or adjacent to the computer room.
1.1.3 Floor Construction

Although the PDP-12 System does not require special flooring, a raised floor is preferable for the following reasons:

Minimum cost of future layout changes

Protection of power and interconnecting cables

Safety of personnel (no cabling to trip over)

Enhancement of the computer site

®Teletype is a registered trademark of Teletype Corporation.

1-1

One type of flooring suitable for a PDP-12 site is the pedestal type shown in Figure 1-1. This flooring allows cable
routing in any direction (e.g., under the floor); it also allows flexibility in the system layout, and minimizes cable
lengths.
Another type of flooring available is the raceway type shown in Figure 1-2 .. This type of flooring however, does
not allow the cable routing flexibility provided by the pedestal type.

10·0479

Figure 1-1 Pedestal Flooring

10-0478

Figure 1-2 Raceway Flooring

The floor should be constructed to allow access to the cabling and be capable of withstanding the weight requirements of the system, personnel, and any other equipment which is to be positioned on the raised floor.

1-2

1.1.4 System Layout
PDP-12 Systems can be ordered under three types of layout plans. The three types are:

Plan A - an unmodified, standard PDP-12 System, or the PDP-12/10, /20, /30, /40 series. This plan
provides a standard configuration, including standard cable lengths to free-standing peripherals
(shown in System Drawings PDPI 2-0-1 through 5, Volume III of this maintenance manual);
Plan B - a configuration similar to Plan A except that either the cabinet-mounted peripheral configuration. or the free-standing peripheral locations differ from DEC specifications;
Plan C - a special PDP-12 installation dictated by the customer's application and built by DEC's
Computer Special Systems group. For such a plan, the customer should prepare a layou! of PDP-12
cabinet and peripheral equipment locations, and submit the layout to DEC for approval. If the
PDP-12 computer console is to be remotely located, the distance from the console to the peripherals
must be specified by the customer; the appropriate interconnecting cable can then be supplied by
DEC.
Operational requirements determine the specific location of the various free-standing peripherals of the system.
The following points should be considered when planning the PDP-12 layout:
a.

Easy observation of 1/0 devices by operating personnel

Adequate work area for installing tapes, disks, allowing access to console, etc.

Proximity of the cabinets and peripherals to any humidity-controlling or air-conditioning
equipment

The final layout is then reviewed by the DEC Sales Engineer and factory engineering personnel to ensure that cable
limitations are not exceeded, and that proper clearances are maintained. When applicable, the DEC Field Service
Branch Manager provides a scaled layout of the Field Service Engineering equipment to be installed in the computer room.
NOTE
If additional sy-stem or console Teletypes are to be located

more than six ft from the computer, inform the Sales
Engineer and DEC will provide the additional cable lengths.
1.1.S Fire and Safety Precautions
The following fire and safety precautions are presented as an aid in providing an installation that affords adequate
operational safeguards for personnel and system components. C0mpliance with industry-acceptable and local
regulations are the responsibility of the system user.

If an overhead sprinkler system is used, a "dry pipe" system is recommended. This type of
system, upon detection of a fire, removes source power from the room and then opens a
master valve to fill the room's overhead sprinklers.

If the fire detection system is of the type that shuts off the power to the installation, a
battery-operated emergency light source should be provided.

If an automatic carbon-dioxide fire protection system is used, an alarm should sound on
release of the co2 to warn personnel within the area.

If power connections are made beneath the floor of a raised-floor installation, waterproof

electrical receptacles and connections should be used.
(continued on next page)

1-3

An adequate earth ground connection should be provided for the protection of operating
personnel.
NOTE
In view of the value of this system, it may be advisable for the
user to consult with his insurance underwriter concerning
security, lo~ due to fire, flood, etc., or other related considerations.

1.1.6 Installation Constraints
The route that the equipment is to travel from the receiving area to the installation site should be studied and
measurements taken to facilitate delivery of the equipment. All measurements and floor plans should be made
available to the DEC Sales Engineer to ensure that the equipment is packed to suit the installation site facilities.
Any restrictions, (such as bends or obstructions in the hallways, elevator or room door openings, and floor loading restrictions, etc.) should be highlighted. If an elevator is to be used for transferring the PDP-12 and its related
equipment to the installation site, the size and gross weight limitations of the elevator must be compared with
those of the computer equipment.
1.1. 7 Environmental Consideration

An ideal computer room environment has an air-distribution system which provides cool, well-filtered, humiditycontrolled air. The room air pressure should be kept higher than the pressure of adjacent areas, to prevent dust
infiltration.

Humidity and Temperature - The PDP-12 System is designed to operate in a temperature range of from 50°F
(10°C) to 110°F ( 43°C), at a relative humidity of 20 to 90 percent with no condensation. However, typical system configurations using I/O devices, such as magnetic tape units, card readers, etc., require an operational temperature range between 65°F (18°C) and 80°F (27.5°C), with 40 to 60 percent relative humidity. Nominal
operating conditions for a typical system are a temperature of 70°F ± 5°F (21°C), with a noncondensation relative humidity of 45 percent ± 5 percent.
Air-Conditioning System - Paragraph 1.3 .3 describes the heat dissipation factors of the PDP-12 System. When
used, computer room air-conditioning equipment should conform to the requirements of the "Standard for the
Installation of Air-Conditioning and Ventilating Systems (nonresidential)", N.F.P.A. No. 90A; as well as to the
requirements of the "Standard for Electronic Computer Systems", N.F.P.A. No. 75.
Acoustical Damping - Some peripheral devices (such as line printers) have a high noise level. In installations that
use a group of high noise-level devices, an acoustically dampened ceiling that reduces noise should be considered
for personnel comfort.
Lighting - A cathode-ray tube display device employing a variable intensity feature is a part of most PDP-12
Systems; the illumination surrounding the computer should, therefore, be capable of being varied to enable the
operator to adjust the ambient light level for comfortable long-term viewing.
Special Mounting Conditions - If the PDP-12 will be subjected to rolling, pitching, or vibration of the mounting
surface (e.g., aboard ship), all cabinetry should be securely anchored to the installation floor by mounting bolts.
Because such installations could require modifications to the system cabinets, DEC should be notified of the
special condition upon placement of the order.

1-4

Cleanliness - The following precautions are recommended by DEC to ensure optimum PDP-12 operation:

Do not use steel wool for cleaning floors in the computer room. The metal fibers can enter
the cabinets and possibly short the electrical components.

To prevent air flow interference, do not place any material on top of the system cabinets.

Use a nonconductor-type nozzle when vacuuming to minimize the possibility of an electrical
accident.

Avoid spilling liquids (coffee, soda, etc.) on the equipment and operating controls.

If available, filtered air should be provided to the computer room.

Static Electricity - Static electricity can be an annoyance to computer room personnel and may (in extreme cases)
affect the operational characteristics of the PDP-12 and related peripheral equipment. If carpeting is installed on
the installation room floor, it should be of a type designed to minimize the effects of static electricity. Flooring
consisting of metal panels or flooring with metal edges should be adequately grounded.
1.2 SYSTEM CONFIGURATIONS
1.2.1 Standard Configurations
There are three standard PDP-12 System configurations; components are detailed in the Systems Drawings,
Volume III of this maintenance manual. ·
System

Drawing Number

PDP-1 2C Basic System

PDPl 2-0-1 Sheet 2 of 4

PDP-l 2B Intermediate System

PDPl 2-0-1 Sheet 1 of 4

PDP-l 2A LINC System

PDPl 2-0-1 Sheet 1 of 4

NOTE
The PDP-12/10, /20, /30, /40 configurations are listed below.
PDP-12/ l 0 Basic Laboratory Instrument System
PDP-12 Dual Instruction set Central Processor
4096 12-bit, 1.6 µs Core Memory
Direct Memory Access Channel
6 Sense Switches
Hardware Signed Multiply Instruction (9 µs)
15 Auto-Index Registers
12 Sense Line Inputs
30-in. Free-standing Cabinet
AD 12 Analog to Digital
DR12
33 ASR Teletypewriter, 10 Char/Sec Paper Tape Reader and Punch

PDP-12/20 Laboratory Instrument Computer-LINC
Includes all of the features of PDP-12/ 10 plus:
TC12
TU56
VC14
VR14
API-12 Multiple level automatic priority interrupt

(continued on next page)

1-5

PDP-12 Advanced LINC
Includes all of the features of PDP-12/20 plus:
MCI 2 4K memory extension
KW l 2-A Real Time Clock
PDP-1 2 Super LINC
Includes all of the features of PDP-12/30 plus:
FPP-1 2 Floating Point Processor

1.2.2 System Expansion
As shown in the drawing referenced on Page 1-5 (Sheets l through 4), a PDP-12 System can be expanded by
addition of the options which are housed in H96 l -C Expander Cabinets. A system can also be expanded with the
use of stand-alone expander cabinets or free-standing peripherals. However, it is important that the maximum
cable lengths between the PDP-12 Cabinet and any additional peripherals be carefully considered. Attention is
directed to System Drawing PDPI 2-0-2, Sheet 2, which lists some of the cables and the lengths. Careful consultation with the DEC Sales Engineer will eliminate any problems that might otherwise be encountered when
expanding a PDP- I 2 System.
1.2.3 1/0 Interface
A complete discussion of the interface requirements of the PDP-12 is presented in Chapter Six of the PDP-12
System Reference Manual (also supplied with each system). Discussed are: the I/O Bus, I/O Cables, logic level
converters and their drive capabilities, etc.
1.3 PREDELIVERY PREPARATION
The size of the system to be installed is the prime consideration in determining the degree of planning and site
preparation required. The following general information is presented as a guide in site preparation and planning.
1.3.l Preliminary Procedures
Prior to receiving the equipment, the customer should:

Determine the location of the installation and the system configuration. If applicable, make
an installation layout diagram, using the information in Paragraph 1-2. Figures 1-3 and
1-4 illustrate PDP-12 Cabinet dimensions and equipment layouts.

Determine the placement of air-conditioning, lighting, power receptacles, etc.

Check the size of doors, passageways, elevators, etc., that could create receiving and/or installation problems. If a problem is noted, DEC must be informed at the time the equipment
is ordered. Special packing/shipping provisions can then be implemented.

Determine the power requirements of the entire system. This information is provided in
Paragraph 1.3.3, System Power Requirements.

The DEC Sales Engineer usually visits the installation site at the time of the sales order and again one month
prior to delivery, to determine the specific requirements for moving system components from the delivery van to
the installation site. Any installation site restrictions or constraints should be noted and reported to the DEC
Sales Engineer.
One week prior to delivery, installation of air-conditioning equipment, electrical and power facilities, lighting, etc.
should be completed.

1-6

BAY 0
PDP-12
BAY A

BAY B

BAY C

RFOB

DEC TAPE
STORAGE
RACK
"1809544
OR BLANK
PANEL

TU55/56

I. TU55 /56
2. MM8I
3. AF01

I. TU55
2. DS32

DEC TAPE
STORAGE
RACK
#1809544
OR BLANK
PANEL

TU55/56

I. TU55 /56
2.MMBI

I. TU55
2. DS32

KW12
PANEL OR
BLANK
PANEL

RSOB

VR12
OR

VR14

1. TU55
2. MMBI

I. TU55
2.DS32

1. PC12
2. BAl2
3.MMBI

I. DF32
2.PC12

72
ADl2 PANEL

.J.

PDP-12

CONSOLE

TABLE

RS08

I
I

FAN

PT08

---- - -

DR12
PANEL
724
PIS

27
AGl2
PANEL OR
BLANK

BLANK

BAl2

- - - - --

BLANK

DM01

DW08-A
12-0255

FLOOR LINE

NOTE:
All dimen1ion1 in inch11

Figure 1-3 PDP-12 Expanded Equipment Layout (see Drawing POPI 2-0-2)

r----------.
MINIMUM
ACCESS
AREA

I
,-18-r--+-~~~~~~~~~~r-~~~--,~~~~..... -

H961-C

- -

X
I
ADDITIONAL 1
H961-C
CABINETS:
- -

-J

~:;::~~~L~

CONTAINER

NOTE:
All dimen11ons are in inches

KSR-35

ASR-35

1--20--i

!---- 40 ---·I

12-0256

Figure 1-4 Minimum PDP-12 Equipment Floor Plan Requirements
(Sec Volume Ill, Drawing POPI 2-0-2)
1-7

1.3 .2 Shipping and Receiving Constraints
Unless otherwise specified to the DEC Sales Engineer at the time of the order, PDP-12 Systems are shipped in the
following manner (see Figure 1-5):

PDP-12 WRAPPED IN PLASTIC
AND SH I PPED IN HEAVY
CARDBOARD OR 1/2-in. PLYWOOD
CONTAIN ER

WOOD AND CARDBOARD CORNER
PACK ING WITH METAL STRAPPING
TO PALLET

7/16-in. BOLT (ONE EACH SIDE)
SECURES PDP-12 TO PALLET

42-in.

/
--------

40 TO 82- in.
~~~~~1
MAXIMUM

M A X I MU M g r o ss sh i pp i n g we i g ht
1300 lbs. (crated) (PDP-12A with
2ea. H961-C cabinets). H961-C
cabinet approximately 300 lbs. each.

Figure 1-5 Packing Details

Domestic and North America
a.

Motor Freight and Padded Van - PDP-12 Systems are shipped as a single integrated package.
The largest configuration normally packed and shipped is the basic PDP-12 Cabinet and two
H961-C Expander Cabinets, terminated and bolted together, and mounted on the same shipping pallet. If additional expander cabinets are included, they will be shipped terminated
and bolted and (to the extent possible) on the same pallet, up to a total of three H961-C Expander Cabinets. Free-standing or additional peripherals are shipped individually on their
own pallets. Packing materials that are used in motor freight or padded van shipments are:
plastic wrapping, cardboard packing, metal strapping, and a cardboard enclosure; bolted to
a wooden shipping pallet.
1-8

Domestic and North American (Cont)
b.

Air Freight - All air freight shipments are crated as described below.

Foreign
a.

Air Freight and Sea Going - All air freight and sea-going shipments are terminated and mounted
together on shipping pallets as described above; wrapped in plastic, secured with cardboard
packing and metal strapping, and crated with 1/2-in. plywood.

Table 1-1 provides general information concerning approximate shipping dimensions and gross weights. These
specifications apply only to standard pac~ing and shipping practices. If the user's constraints dictate, other shipping methods can be implemented. However, close liaison with the user, DEC Sales Engineer, and DEC manufacturing with reasonable lead time is required.
Table 1-1
Standard PDP-12 Shipping Specifications
PDP-12

Height

Dimensions
Width
Depth

Weight

Storage Temperature

C, /10

78 in.

45 in.

42 in.

600lb*

40° to l 10°F
(5° to 45°C)

B, /20

78 in.

45 in.

42 in.

900lb*

40° to l 10°F

A, /30

78 in.

45 in.

42 in.

1000 lb*

40° to 110° F

/40, LOP

78 in.

45 in.

64 in.

1600 lb*

40°tol10°f

2 H961-C Expander Cabinets

78 in.

45 in.

82 in.

1800 lb*

40°tol10°f

Expanded Systems

*Includes the packing and crating materials.

1.3.3 System Power Requirements
The total current required by the PDP-12 installation can be determined by adding together all current requirements associated with each cabinet and peripheral device. From this data, the type and quantity of ac power
connectors and receptacles can be determined. A minimum of one ac connector for each cabinet and one ac connector for each free-standing peripheral should be provided.
PDP-12 Cabinet Power Requirement - A standard PDP-12 Single Processor Computer System requires up to
3000 Btu/hr average, up to 6000 Btu/hr maximum, and up to 17.SA at 115 Vac, 60 Hz.

1.3.4 Source Power Requirements
The PDP-12 can be operated from a 100, 115, 200, 215, or 230V, 50 Hz ac power source; or from a 120/240V
60-Hz ac power source. The primary ac operational voltages should be maintained as closely as possible to the
nominal value. Line-voltage tolerance must be maintained within± 10 percent of the nominal values, and the
50/60 Hz line frequency should not vary more than ±2 Hz.
Primary power to the system should be provided on a line separate from lighting, air-conditioning, etc., so that
computer operation will not be affected by voltage surges or fluctuations.

1-9

The PDP-12 Cabinet ground should be connected to the building power transformer ground. Any questions
regarding power requirements and installation wiring should be directed to the DEC Sales Engineer.
Primary Power Receptacles - The installation site primary power line must terminate in Hubbell Wall rec~ptacles
(or equivalent) to be compatible with the PDP-12 power line Hubbell connector. The Hubbell wall receptacle part
numbers are shown in Table 1-2. Figure 1-6 shows the primary power wall receptacles and the points where the
site primary power lines are terminated. One receptacle is required for each cabinet and each free-standing
peripheral.

Table 1-2
Hubbell Wall Receptacle Part Numbers
Line Voltage

Hubbell Receptacle Part Numbers

100-200 Vac, 50-60 Hz, 30A Service

Receptacle 3330-G (3330 may be used)
Cap
3331-G (3331 may be used)

200-240 Vac, 50-60 Hz, 20A Service

Receptacle 7310-G (7310 may be used)
Cap
3321-G (3321 may be used)

SERVICE OUTLET
t20V 60Hz SINGLE PHASE
t5A/UGND
NEUTRAL~LINE t

FRAME GROUND

~
CAUTION

Wll•n n•11trol I• n•f orollobl• for tit•
obor• ••rrlt:•, • ""'Pl••I• of Ill•
obo,,. tlHI'" •lloll b• 11••tl, b11f botll
por11ll•I •lot• 61101/ b• •llorf to"''"'"'
po/orlz•tl poroll•I blot/•,,,,,,. (t:op1J
from flttln,.

NEUTRAL OR
LINE 2

RECEPTACLE No. SHO·G
CAP No. 353t·G
t t 5V 60Hz SINGLE PHASE
30A TWIST-LOCK

RECEPTACLE No. 7310-G
CAP No.H2t·G
nov 50Hz SINGLE PHASE
20A TWIST-LOCK
09-0414

Figure 1-6 Hubbell Wall Receptacle Connector Diagram

1-10

1.3.5 Primary ac Power Cables
Primary ac power cables are three-wire cables that interconnect the installation-site source power to the PDP-12
power supplies. The cables are connected at the factory to the PDP-12 power supplies for either 50 Hz or 60 Hz
operation. All cabinets (excluding cabinets having only DECtapes) have a self-contained power supply and an ac
power cable.
Each wire in the power cable is color-coded (refer to Table 1-3). The cable for the PDP-12 Model 724 Power
Supply is connected to circuit breaker CBI (see Drawing D-CS-724-0-1, Volume III).
Table 1-3
Power Cable Line Identification

Line

Pigtail Information
Wire Color

Green
White
Black

Frame Ground
Neutral/Line 2
Line 1

Terminal Strip Nomenclature
Frame Ground
Neutral or Line 2
Line 1

CAUTION
a. The green wire is the cabinet frame ground and
does not carry load current; however, it must be
connected for safety reasons. This wire must be
securely connected from the PDP-12 Cabinet to
the grounding point on the primary power source.
b. The white or light gray wire is the neutral lead
(common, ac return, or cold lead) and must never
be used for purposes of grounding the PDP-12
Cabinet.

1.3.6 Service Outlets
Duplex ac convenience outlets should be provided to power test equipment when maintenance tasks are performed.
The duplex outlet (see Figure 1-6) should be located near the PDP-12 and its related equipment, and should be
rated at 120Vac±15 percent 50/60 Hz, 20A. These outlets should be separately fused.
1.3.7 Cabling
DEC cabinet interconnecting cables are of standard lengths and are factory-installed. If the cabinets must be
shipped separately because of shipping or receiving conditions, the cabinet interconnecting cables are reconnected
at the installation site. The termination point of each cable is identified. Cables for an expanded system are
measured and ordered in accordance with the DEC-approved installation layout. The part number and required
cable length are specified by the DEC Sales Engineer for each cable or group in the PDP-12 System.
BC08A-D and W033 cables provide signal connections between the computer and the optional equipment in expander cabinets or free-standing peripherals. These cables are connected by plugging the respective connectors
into standard module receptacles. Cables connect to cabinets through a drop panel in the bottom of the cabinet.
Subflooring, while recommended, is not absolutely necessary because cabinet levelers and casters elevate the
cabinets high enough from the floor to provide sufficient cable clearance. Cable detail discussions are included in
Chapter 5 of the PDP-12 System Reference Manual.

1-11

1.4 UNPACKING, INSTALLATION AND INSPECTION
1.4.1 General
The shipping containers may be handled by a fork-lift truck or other pallet-handling equipment. The containers
should be taken to the installation site and placed near the final locations of the equipment cabinets.
IMPORTANT
Do not attempt to unpack or install the system until DEC has
been notified and a Field Service Representative is present, or
the equipment warranty may be affected. Consult with the
DEC Sales Engineer concerning warranties.
1.4.2 Cabinet Unpacking
The following procedures should be followed for unpacking the PDP-12 Cabinet:
Step

Procedure
Remove the outer shipping container.
NOTE
The container may be either heavy corrugated
cardboard or 1/2-in. plywood. In either case, remove all metal strapping first, and then remove
any fasteners and cleats securing the container to
the pallet. If applicable, remove the wood framing
and supports from around the cabinet perimeter.

After removing the outer container (if applicable), remove the cardboard containing the console table.

Remove the polyethylene cover from the cabinets.

Remove the tape or plastic shipping pins,. as applicable, from the cabinet(s) rear
panel door, and open the door.

On the PDP-12 Cabinet, unscrew the shipping locks which hold the module
rack (plenum door). Open the plenum door and remove all packing materials
from inside the cabinet. Strip the tape from the modules and remove the
plastic foam packing.

Remove the travel clip from the front panel door. The clear plastic mask
which covers the Data Terminal Panel may be removed or left in place, if
desired, as added protection.

Unbolt the cabinet(s) from the shipping pallet. Access to the bolts, located
on the lower supporting siderails, is through the rear panel doors. Remove
the bolts.

Use wooden blocks and planks to form a ramp from the shipping pallet to
the floor.

Raise the leveling feet above the level of the roll-around casters and carefully
roll the cabinet(s) onto the floor.

Roll the system to the proper location for installation.

1-12

1.4.3 Cabinet Installation
The PDP-12 Cabinets are provided with roll-around casters and adjustable leveling feet. It is not necessary to bolt
the cabinet to the floor unless conditions indicate otherwise (e.g., shipboard installation). Cabinet installation
procedures are as follows:
Step

Procedure
With the cabinets positioned in the room, install, if applicable, the filler strips
between cabinet groups (filler strips are attached to the end of a cabinet group).
Remove the four bolts securing the front and rear filler strips, butt the cabinet
groups together while holding the filler strips in place, and rebolt through both
cabinets and the filler strips. Do not tighten the bolts securely at this time.

Lower the leveling feet, making sure that the cabinet(s) are not resting on the
roll-around casters but are supported on the leveling feet.

Level all cabinets with a spirit level and ensure that all leveling feet are seated
firmly on the floor.

Tighten the bolts that secure the cabinet groups together and then recheck
the cabinet leveling. Again ensure that all leveling feet are seated firmly on
the floor.

Examine all modules and connectors in the main computer cabinet to be certain that they are all properly seated in their slots. Check to see that no packing
material or other loose items may have fallen into the interior.

Connect the power cord to the 30-A Hubbell twist-lock receptacle. The computer is now ready for preliminary checkout.

1.4.4 Cabinet Inspection
After removing the equipment packing material, inspect the equipment. Report any damage to the local DEC
sales office. Inspection procedures are as follows:
Step

Procedure
Inspect the external surfaces of the cabinets and related equipment for surface,
bezel, switch, and light damage, etc.

Remove any remaining shipping bolts from the rear door and open the rear
door of the cabinet. Inspect the cabinet internally for console, processor,
and interconnecting cable damage; loose mounting rails; loose or broken
modules; blower or fan damage; loose nuts, bolts, screws, etc.

Inspect the wiring side of the logic panels for bent pins, cut wires, loose external components, and foreign material. Remedy any defects found.

Inspect the power supply for the proper seating of fuses and the proper
seating of power-connecting plugs.

Remove any shipping bolts and tape from the side runners of the tape transports and display units, if part of the system.

Place the table under the control console.

1-13

1.4.S Teletype Unpacking
Step

Procedure
Open the Teletype carton, and remove the packing material. Remove the back
cover from the stand. Remove and unwrap the copyholder, chad box, and power
pack. Remove the stand from the shipping carton. Remove the Teletype console from the carton, holding it by means of the pallet attached to the bottom.
Snap the power pack in place at the top of the inside front of the Teletype
stand. Remove the Teletype console from the pallet, and mount it on the
stand. Connect the Teletype console to the power pack (a six-lead cable
attached at the console is connected to the power pack by means of a white
plastic Molex 13 7 5 Female Connector which mates with a male output plug
on the power pack). Pass the three-wire power cable, and the seven-conductor
signal cable (which is terminated in a type W076 Cable Connector Module)
through the opening at the lower left-hand corner of the Teletype stand; then
replace the back cover of the stand by means of the two mounting screws.

Dress the Teletype cable under the PDP-12 Cabinet, through the large opening
and into logic frame slot N2. It is necessary that this cable be dressed through
the cable clamp at the lower rear corner of the logic frame where the power
cables are secured. A second clamp may be desirable at the bottom of the
PDP-12 Cabinet to ensure that sufficient strain relief is provided regardless
of Teletype position.

Connect the three-prong male connector of the Teletype power cable to the
receptacle at the rear of the computer power supply chassis.

Install a roll of printed paper into the Teletype keyboard/printer, and install
a tape in the punch as described in the Teletype technical manual.

1.4.6 Teletype Installation and Setup
The following procedures describe the sequence for preparing the Teletype(s) for power turn-on. Procedures for
installing paper in the printer and in the reader/punch are included in Paragraph 1.5.2.

Models 33 ASR and 33 KSR - Perform the steps listed below.
Step

Procedure
After unpacking the Teletype, lift the cover and remove the wires that secure
the type carriage and punch levers.

Inspect the Teletype for external damage; loose screws, nuts, bolts, or code
bars.
NOTE
Included with the DEC manuals are three Teletype
manuals concerning the Teletype Model 33 ASR.
Volume 1 gives instructions for installing the console and preparing it for operation.

Teletype Console - The Teletype console has been modified at DEC, checked out, and repacked, using the
original materials and containers. After assembling the Teletype console and stand, follow the instructions of

1-14

the Teletype manual Volume 1, Chapter 2; however, the following considerations must be observed as listed in
the Procedure column:
Procedure

Step

Disregard Sections 2.03 through 2.13 and 2.15 of the Teletype Manual. The
answer-back drum need not be coded.
2

Disregard Sections 2.21 through 2.23; the electrical connections to the DECsupplied cable and connector have been made.

Observe the notes in Sections 3.01 and 3.02. The paper is friction-fed.

Disregard Sections 3.16 through 3. 21 and Section 4.
NOTE
At this point, the operation of the Teletype keyboard, printer, tape reader, and tape punch, may
be tested off-line, following the procedure described
in Paragraph 1.5.2.

1.4. 7 Prewired Option Installation
The installation of the internal options involves the addition of the logic modules in the proper prewired locations
and is usually performed at the factory. The computer must be turned off before inserting or removing any
modules in the logic frame. Refer to the module utilization drawings in Volume III of this Maintenance Manual
for the locations of each module of all internal options; refer to Chapters 3 and 4 of this volume for specific installation and checkout procedures.
1.4.8 Peripheral Equipment Inspection
All peripheral equipment should be inspected for internal and external damage. This includes inspection of magnetic tape and DECtape transport heads, motors, paper-tape sprockets, etc.
CAUTION
Do not operate any peripheral device that employs motors,
tape heads, sprockets, etc., if the latter are damaged.
1.4.9 Miscellaneous Items
Open the other cardboard boxes containing program tapes, Teletype paper, blank paper tape, manuals, etc. Check
the contents of each box against its enclosed packing list. Note any missing items, and bring them to the
attention of the DEC Sales Office.
1.5 CHECKOUT
1.5 .1 Preliminary Opera ting Checks
Set the main circuit breaker CBI, located on the rear of the 724 Power Supply chassis, to ON. CB 1 applies ac
power to the power supply only, and may be left on continuously. Prior to applying power, measure each power
bus and ensure that no direct short exists across any bus (minimum 2 ohms).
Insert the power key into the OFF /ON/LOCK switch lock on the computer console; turn the key to the ON
position. The panel lights should glow in a random pattern; the fans inside the cabinet will start, and the
Teletype motor will start unless the Teletype switch is turned OFF.

1-15

1.5.2 Teletype Test
Insert a roll of printer paper in the Teletype console, and a roll of paper tape in the tape punch (refer to the
Teletype manual for the loading procedure). Turn the Teletype power switch ON. Set the LINE/OFF/LOCAL
switch to LINE, and depress the tape punch ON button. Strike several keys; there should be no action by the
punch or the printing wheel.
Set the LINE/OFF/LOCAL switch to LOCAL. Strike each key in succession. Printer characters should appear on
the Teleprinter paper. and corresponding codes should be punched in the paper tape. After a few inches of tape
have been punched, press the punch OFF button. Press RELEASE; pull out several inches of the punched paper
tape and tear it off. Place the punched tape in the paper-tape reader so that the beginning of the punched section appears at the reading station. Set the reader switch to START. As the tape is read, a duplicate of the
original printed sequence should appear on the paper. When it appears that the Teletype is operating properly,
stop the reader and remove the tape. Set the console switch to LINE.
1.5.3 Computer Memory Test
Turn the console power key ON. Test the addressing and memory read/write functions as follows:
Step

Procedure
Set the LEFT SWITCHES to 0400.

Set the RIGHT SWITCHES to 0000 (all depressed).

Depress FI LL once.

Depress and release FILL STEP eight (8) times.

Set the RIGHT SWITCHES to 7777 (all up).

Depress and release FILL STEP eight (8) times.

Depress EXAM once.

Depress and release STEP EXAM 16 times, and observe the contents of the
MEMORY ADDRESS and MEMORY BUFFER register indicators after each
time. The MA should start with 0400 to 0407, and 7777 while the MA steps
from 0410 to 0417.
NOTE
Complete memory operating checks are contained
in Paragraph 3 .1.

1.5 .4 RIM Loader
Using the console switches, enter the RIM Loader in memory as follows:
Step

Procedure
Set the LEFT SWITCHES to 7756.

Set the RIGHT SWITCHES to 6032 (the first instruction of the RIM
Loader program). Actuate FILL key once, followed by FILL STEP key.

Repeat Step 2 for each succeeding instruction in the program, as shown
in the sample program following, but using only the FILL STEP key.
Check the MA and MB indicators after each instruction is deposited. The
MA should step from 7756 to 7775; the MB should contain the code of
the instruction just deposited.
(continued on next page)
1-16

Step

Procedure

Check the entire program by repeating Step 1, then depressing the EXAM key
followed by STEP EXAM (same as Step 3 ), examining the MB and comparing
it with the program below.
Addre~ (MA)

Instruction (Right Switches)

7756
7757
7760
7761
7762
7763
7764
7765
7766
7767
7770
7771
7772
7773
7774
7775

6032
6031
5357
6036
7106
7006
7510
5357
7006
6031
5367
6034
7420
3776
3376
5356

1.5.5 Running MAINDECs
The set of MAINDEC diagnostic programs is used to check out the operations of each section of the PDP-12
System. Each tape is in one of two formats: RIM or Binary. Each requires a different loading procedure.

RIM - RIM (Read In Mode Loader) tapes are identified by the fact that channel 7 of the first and every fourth
tape character is punched.
Procedure

Step

Set the MODE switch to 8 MODE.

Depress and release the I/O PRESET key.

Place the punched tape in the paper-tape reader, with leader (section of tape
with only channel 8 punched) positioned at the Read station; push down the
cap until it latches; be certain that the drive sprocket engages the feed holes.

Set the reader switch to ST ART.

Set the LEFT SWITCHES to 7756. Make certain that no stop keys (FETCH,
EXECUTE, SING. CYCLE or STOP) are depressed.

Press START LS. The tape will move through the reader as the program is
loaded into memory.

When the trailer section of the tape (channel 8 punched) reaches the Read
station, press and reset the console STOP key, move the reader switch to
FREE, and remove the tape. The program is ready to run.

BIN - BIN (Binary) tapes have leaders and trailers similar to RIM tapes, but they must be loaded by a special
program. The Binary Loader is itself in RIM format, and is loaded by the procedure above. Once it is in memory,
any Binary tape may be loaded as follows:

1-1 7

Step

Procedure
Set the LEFT SWITCHES to 7777.

Set the MODE switch to 8 MODE.

Depress and release the I/O PRESET key.

Mount the tape as described in RIM loading procedures.

Depress and release START LS.

When the program is loaded, the tape stops automatically when the first
trailer code is sensed.

After the tape stops, examine the Accumulator indicator lights. They should
all be off. If they are not, try reloading the tape. (The state of the LINK
indicator light is not significant.)

Once it has been determined that both RIM and Binary tapes can be loaded successfully, run the MAINDECs in
sequence as listed in Appendix D. Follow the operating instructions provided in the write-ups for each program.

1-18

CHAPTER 2
MAINTENANCE

2.1 INTRODUCTION
This chapter provides instructions for the service and maintenance of the PDP-12 Computer System; these
instructions are written for persons who are familiar with the PDP-12 equipment. Lengthy descriptions explaining the use of test equipment have been avoided, except where special test setups are required. This chapter is
divided into the following sections:
Section 1
Section 2
Section 3
Section 4
Section 5

Introduction
Equipment
Preventive Maintenance
Corrective Maintenance
Troubleshooting

From a maintenance standpoint, the PDP-12 has combined two functional subsystems into a common processor:
a PDP-8/I general-purpose computer and a LINC (Laboratory INstrument Computer). In such a system, interactive hardware and software and modes of operation (8-Mode and LINC-Mode) demand that a systematic maintenance program be initiated upon installation and faithfully followed thereafter. A systematic preventive
maintenance program is a deterrent to system failures. Proper application of such a program is an aid to both
maintenance personnel and the user because detection and prevention of probable failures can reduce maintenance
and downtime to a minimum. All units of the PDP-12 System are designed to realize a high reliability.
2.2 MAINTENANCE EQUIPMENT
Special tools and test equipment required for maintenance are listed in Table 2-1. Except for DEC equipment,
suggested commercial brands are given for purposes of specification only; their being mentioned in this manual
does not constitute exclusive endorse~ent.
Table 2-1
Maintenance Equipment
Equipment

Specification

Model or Type

Multimeter

1OK ohms/V - 20K ohms/V

Triplett Model 310

Oscilloscope

DC to 50 me with calibrated deflee ti on factors from 5 m V to
lOV/div. Maximum horizontal
sweep rate of 0.1 µ.s/div. Delaying sweep is desirable and dual
trace is a necessity.

Tektronix Type 453

'(continued on next page)
2-1

Table 2-1 (Cont)
Maintenance Equipment
Equipment

Specification

Model or Type

Probes

XI 0 with response characteristics
matched to oscilloscope

Tektronix Type P60 I 0

Clip-on Current Probe

2 mA, mV or 10 rnA, rnV

Tektronix Type P6019 with
passive terminator
Tektronix

Recessed Probe Tip
(2 ea.)
Unwrapping Tool

Wire-Wrap Tool

30 gauge

Gardner-Denver 505-244-475

24 gauge

Gardner-Denver 500130

30 gauge

Gardner-Denver A-20557-29

24 gauge

Gardner-Denver A-20557-12

30-Gauge Bit for Wrap
Tool

Gardner-Denver 504221

Sleeve for 30-Gauge Bit

Gardner-Denver 500350

Spray Paint

Yellow

Spray Paint

Green

Spray Paint

DEC black

Module Extender (2)

DEC No. W982

Jumper Wires

Assorted lengths affixed with
30- and 24-gauge terrni-point
connectors

Screwdriver

6-in. non-conductive shaft
DEC Type 142

Field Service Kit
Precision Voltage Source

-lVto+lV0.1%

Electronic Development Co.

PDP-12 DIAL Maintenance
LINCtape, Assorted Writeups and Back-up Paper
Tapes*
*Supplied with the PDP-l 2A, PDP-l 2B, /20, /30, and /40.

2.2.1 Maintenance Test Programs
Appendix D lists the software designated DEC**; collectively, these programs provide a complete check of the
logic for the PDP-12, and the prewired options and software.
Functionally, the programs fall into two categories: diagnostic and reliability. The diagnostic tests isolate the
genuine go/no-go type of hardware failures that are easily recognizable. The reliability programs isolate failures

**See Appendix D for a detailed listing.

2-2

that are more difficult to detect because they are marginal in nature and/or occur infrequently or sporadically.
The family of test programs is written so that, when run successively, they test the processor, beginning with small
portions of the hardware and gradually expanding until they involve the entire system.
The test programs are made up of numerous self-contained routines. In those programs that are diagnostic in
nature, each routine is involved with a specific circuit or logic function. In the simplest form, for example, a
single routine is used to check each leg of an AND gate. When the diagnostics have been run to completion, the
processor has been exercised to the extent that it has been proved capable of executing all instructions. However,
such proof is conditional, because it is based on the execution of instructions using pre-established constants as
operands.
Further tests are necessary to establish that the computer properly executes instructions, using operands and
various combinations of operands other than those used in the diagnostics. The reliability test programs provide
this additional testing. Primarily, each routine in the reliability test programs establishes a loop whereby a specific
instruction or group of instructions is repeated many times. Each repeat is executed using operands, the magnitudes of which are established by a pseudo-random number generator, or a binary upcount. This procedure makes
certain that machine capabilities are checked under a maximum number of unique conditions.
When an error is detected with diagnostics, the program halts or enters an error handling routine. The reason for
the error may then be determined by using the console controls and indicators, maintenance switches, error typeouts on Teletype, and the program listings included in the software package. The use of the data switches for
selecting error handling is defined in the MAINDEC write-ups provided with the software package.
2.2.2 Mounting DIAL MAINTENANCE Tapes
The following procedure is to be used when loading tapes on the LINCtape transports:
Step

Procedure
Mount a LAP6-DIAL MAINTENANCE tape on any tape transport. Advance
tape (right to left) out of the end zone (Approx. 6 ft).

Set WRITE ENABLE on, turn the thumbwheel switch (unit selector) to 0,
depress REMOTE.

Set 0701 (RCG) in the LEFT SWITCHES, set 7300 in the RIGHT SWITCHES
(all other switches to 0).

Set MODE switch to LINC; depress I/O PRESET.

Depress DO key; when tape motion stops, depress I/O PRESET followed by
START 20.
NOTE
A copy of the DIAL MAINTENANCE LINCtape
is provided to PDP-12A, PDP-12B, /20, /30 and
/40 users. Users of PDP-12C, /10 configurations
will be provided with the appropriate paper tapes.

2.3 PREVENTIVE MAINTENANCE
Preventive maintenance consists of procedures that are performed prior to the initial operation of the computer,
and periodically during its operating life. These procedures include visual inspections, cleaning, mechanical
checks, and operational testing. A log which indicates the performance history and rate of deterioration must
be kept for recording specific data; such a record can be used to determine the need and-time for performing
corrective maintenance on the system.

2-3

Scheduling of computer usage should always include specific time intervals that are set aside for scheduled
maintenance purposes. Careful diagnostic testing programs can then reveal problems which may occur only
intermittently during on-line operation.
2.3.1 Scheduled Maintenance
The PDP-12 must receive certain routine maintenance attention to ensure maximum life and reliability to the computer system. DEC suggests a schedule of 1000 hours for electrical inspection, and 500 hours (or every month)
for mechanical inspection.
Daily Maintenance - The LINCtape heads and guides should be cleaned whenever they are dirty; typically, once
a day.
Weekly Maintenance - Time should be scheduled each week to operate the applicable MAINDEC programs as
listed in Appendix D. Run each program for a minimum of five minutes; take any corrective action necessary at
this time; and log the results. External cleanliness of the system should also be maintained on a weekly basis.
Preventive Maintenance Tasks - The following tasks should be performed on at least a three-month schedule:

Step

Procedure
Gean the exterior and interior of the computer cabinet, using a vacuum cleaner
and/or clean cloths moistened in nonflammable solvent.

Oean the air filter. Use a vacuum cleaner to remove accumulated dirt and dust,
or wash with clean hot water.

Lubricate slide mechanisms and casters with a light machine oil. Wipe off
excess oil.

Visually inspect equipment for general condition. Repaint any scratched areas
with DEC black, yellow, green, or Krylon glossy white No. 1501.

Inspect all wiring and cables for cuts, breaks, fraying, wear, deterioration,
kinks, strains, and mechanical security. Tape, solder, or replace any defective
wiring or cable covering.

Inspect the following for mechanical security: key switches, control knobs,
lamps, connectors, transformers, fans, capacitors, etc. Tighten or replace as
required.

Inspect all module mounting panels to be sure that each module is securely
seated in its connector. Remove and clean any module which may have
collected excess dirt or dust.

Inspect power supply components for leaky capacitors, overheated resistors,
etc. Replace any defective components after correcting any fault condition.

Check the output of the 724 Power Supply as specified in Table 2-2, Power
Supply Specifications. Use a multimeter to make these measurements without disconnecting the load. The outputs of the supply are not adjustable;
therefore, if any output voltage is not within tolerance, the supply is considered defective, and corrective maintenance should be performed.

Run all MAINDEC programs to verify proper computer operation. Each
program should be allowed to run for at least five minutes.

Perform all preventive maintenance operations for each peripheral device
included in the PDP-12 System, as directed in the individual maintenance
instructions supplied with each peripheral device.

Enter preventive maintenance results in the log book.

2-4

Table 2-2
Power Supply Specifications
Voltage

Current

Use

1SV (rms) ± 20%

Panel Lights

+SV, ± S%

20A

Logic

-lSV ± 10%

Keys and Switches
Sense Amplifier
Main Supply

-lSV ± 10%

Sense Amplifier Slice
Reader Clock

-30V ± 10%

Memory Supply, (-)
Teletype

+lOV ± 20%

R-Series Modules

2.4 CORRECTIVE MAINTENANCE
The PDP-12 is constructed of reliable TTL M-series modules. Proven reliability of this circuitry ensures relatively
little equipment downtime due to logic failure. If a malfunction occurs, maintenance personnel should analyze
the condition and correct it as indicated in the following procedures. Table 2-1 lists the equipment and tools
necessary for this task; however, the best corrective maintenance tool is a thorough understanding of the physical
and electrical characteristics of the equipment. Personnel responsible for maintenance should be familiar with the
system concept, the logic drawings, the theory of operation of the specific module circuits, and location of
mechanical and electrical components.
The first step in repairing a reported malfunction is to isolate the problem. In a hardware-software system environment such as the PDP-12, the first step is to determine whether the problem lies in the hardware, the software, or both. The only practical way of accomplishing this is by maintaining good communications between the
operator/programmer and maintenance personnel.
Until the problem is isolated to either hardware or software, the cooperation of all parties concerned is essential.
A step-by-step procedure should be used to trace the problem until a point is reached where all the inputs (conditions) to an element are correct, but the output is not correct. The faulty element should then be repaired.
Where necessary, the element itself may be subjected to step-by-step fault location (from output to input) until
the source of the problem is found.
It is virtually impossible to outline all specific procedures for locating faults within digital systems such as the

PDP-12. However, diagnosis and remedial action for a faulty condition can be undertaken logically and systematically in the following phases:

Preliminary Investigation

System Troubleshooting

Logic Troubleshooting

Circuit Troubleshooting

Repairs and Replacement

Validation Tests

Recording
2-S

2.4.1 Preliminary Investigation
Before beginning troubleshooting procedures, explore every possible source of information. Gather all avaihble
information from those users who have encountered the same problem and check the system log book for any
previous references to the problem or to a similar one.
Do not attempt to troubleshoot by using complex system programs. Run the MAINDEC programs and select the
shortest, simplest program available to exhibit the error condition. MAINDEC programs are carefully written to
include program loops for assistance in system and logic troubleshooting.
2.4.2 System Troubleshooting
Once the problem is understood and the proper program is selected, the logical section of the system at fault
should be determined. Obviously, the program which has been selected gives a reasonable idea of what section of
the system is failing. However, faults in equipment which transmits or receives information, or improper connection of the system, will frequently yield indications similar to those caused by computer malfunctions.
Reduce the program to its simplest scope loop and duplicate this loop in a dissimilar portion of memory to verify,
for instance, that an operation failure is not dependent upon memory location. This process can aid in distinguishing memory failures from processor failures. Use of this technique often pinpoints the problem to a few modules.
System troubleshooting is the first step towards isolating and repairing a machine malfunction. If the machine
cannot be started, refer to Section 2.5.2. If the machine is running, determine that hardware, not software, is
causing the problem. If the problem is occurring with DEC software (LAP6-DIAL, FORTRAN, etc.), obtain a
certified copy of the program, in good condition, and attempt to repeat the malfunction. Generally, a recurring
problem indicates a logic failure. If the problem occurs only with the user's software, an analysis of the failing
program must be made. Use of the FETCH STOP, EXECUTE STOP, and SINGLE STEP is recommended. Some
other items to check in the user's software are special bit assignments and functions. Are TRAP, NO PAUSE, etc.,
being used properly? Are memory fields being used properly? Is the program making unwarranted assumptions;
i.e., assuming that the accumulator will be clear on start-up, etc.?

In general, attempt to isolate the problem to a major system; then exercise that system with the MAINDEC
diagnostics. If necessary, proceed to logic troubleshooting and repair.
2.5 TROUBLESHOOTING TECHNIQUES
2.5.1 Introduction
A prerequisite to this section is a thorough understanding of the information in Section 2.4. This section assumes
a cold start, i.e., the machine has just been unpacked (see Chapter 1), or it was previously shut off. The procedure
is arranged in a definite order of precedence, and should be followed as closely as possible.
WARNING
Maintenance procedures should be performed by qualified
service personnel only.
High voltages are present within portions of the equipment
and are potentially dangerous. All safety precautions must
be observed.
Inherent implosion protection is considered in the CRT design.
However, the tube may be damaged if it is subjected to rough
treatment or dropped while being removed from or installed
in the display. Caution, therefore, must be exercised during
these operations.

2-6

2.S.2 Comole Checks
Assuming a cold start, check the following console functions. If any malfunctions occur, repair the problem before
continuing with the procedure.
Procedure

Step

Power on - Are IR bits 0, 1, and 2 set (on), and is the CP in 8 MODE; is
RUN off*, and is power up to specification (refer to Table 2-2)?
2

1/0 PRESET - Does the AC clear? Does it set the INST FIELD and
DATA FIELD to 2 and 3, respectively? Are the INSTRUCTION REGISTER
bits 0, 1, and 2 still set to the one state (on) (ignore any other bits)? Can
both modes be selected? Do all other indicators remain unchanged?

FILL - Do the RIGHT SWITCHES transfer to the MB? Do the LEFT
SWITCHES transfer to the MA?

EXAM - Do the LEFT SWITCHES transfer to the MA? Do the contents
of the location addressed by the MA transfer to the MB?

FILL STEP - Do the RIGHT SWITCHES transfer to the MB? Do the RUN
and INT PAUSE lights illuminate? Do the contents of the MA increment?
Do the contents of the new location addressed by the MA transfer to the MB?

STEP EXAM - Do the contents of the MA increment? Do the contents of
the new location addressed by the MA transfer to the MB?

AUTO RESTART - Can FILL STEP and STEP EXAM be auto-restarted?
Does the AUTO light illuminate?

Set the MODE switch to 8 MODE and depress and release 1/0 PRESET.
While depressing both the AUTO and the FILL STEP keys, sequentially set
the AUTO RESTART DELAY - COARSE (starting at position 4) to position
3; then to position 2, then to position 1. Note that the MEMORY ADDRESS
register fills (counts up) at a slower rate as the AUTO RESTART DELAY COARSE selector is moved through the four positions. Check the AUTO
RESTART DELAY - FINE vernier adjustment in all COARSE positions.

Examine memory for any bits that may be picked up.

Set RIGHT SWITCHES to 7777 (all ls); repeat Steps 8 and 9.

Examine memory for any bits that may be dropped.

Depress SING STEP key.

Depress START 20.

Does the MA = 0020?

Does the PC = 0021 ?

Does the MB = 7777?

Does the IR= 7777?

Reset SING STEP; clear memory; depress STOP key.

(continued on next page)
*Unless the KP 12 Power Fail Option is installed and switched ON.

2-7

Step
15

Procedure
Depress START 400.

Does the MA = 0400?

Does the PC = 0401?

Does the MB = 0000?

Does the IR= 0000?

Reset STOP; depress CONT.

Does the RUN light illuminate?

Does the MA and PC cycle through 4K or memory?

Do the AC indicators glow dimly?

Are the FETCH and EXECUTE indicators set (glow)?

Set and reset STOP key; depress I/O PRESET key with MODE switch set to
LINC Mode; fill LINC memory field 2 with 0016s (NOP).

Depress the STOP key.

Depress START 20.

Does the MA = 4020?

Does the PC =4021 ?

Does the MB = 0016?

Does the IR = 0016?

Reset the STOP key; depress CONT.

Does the RUN light illuminate?

Do the MA and PC cycle through IK of memory? (4000-5777)

Does the AC remain cleared?

Depress SING STEP.
Does the computer stop?

2.~.3

Depress CONT repeatedly. Does the computer appear to stay in the FETCH
state?

Depress and hold AUTO RESTART; depress CONT; release all switches.
Does the computer cycle through 1K of memory at a rate determined by
AUTO RESTART DELAY, COARSE and FINE adjustments?

Set several different instructions into the LEFT SWITCHES; depress DO.
(Be sure that the CP is in the proper mode for each instruction.) Does the
CP react to each instruction as expected? If the CP performs these operations
successfully, manual timing, memory timing, and CP timing are approximately
correct. Proceed with system troubleshooting.

LINC-Mode Processing

LINC-Mode processing encompasses the entire LINC instruction set, the A/D converters, and D/ A converters.
Troubleshooting the LINC-Mode portion of the PDP-12 is best achieved by using the diagnostic programs stored
on magnetic tape, thus providing the most rapid method of exercising the processor. If the LINCtape portion of

2-8

the computer is inoperative and the tapes cannot be read in any manner, refer to Paragraph 2.5.5, TCl 2 Tape
Subprocessor. Other methods of reading tape include reading entire tests manually, or reading single blocks. If
necessary, read a block using the ROE instruction, thereby bypassing the checksum logic.
A confidence check of module and timing stability can be made by using MAINDEC-12-DOBA (Instruction Test).
This program exercises most of the instructions and addressing modes used in LINC-Mode processing. If no
failure can be found with this test, use of the more advanced diagnostics is necessary. Refer to Appendix D for a
description and applications of these tests.
Aggravation (vibration or heating) of the system is advisable only when an intermittent failure cannot be found
with the LINC-Mode diagnostics. Vibrate the modules, using a nonconducting rod 8 to 12 in. long. Extreme
caution should be followed when vibrating memory or single modules.
2.5.4 8-Mode Processing
8-Mode processing includes the entire PDP-8 family instruction set, memory, Teletype, and most of the available
(standard and optional) peripherals.
Since most of the 8-Mode diagnostics are relatively short, it is not necessary to have either the TCI 2 (LINCtape
Control) or the LINC-Mode processing facility operational. However, if they are available, use of the LINCtape
DIAL MAINTENANCE diagnostics is recommended.
The 8-Mode MAINDEC diagnostic programs are written and arranged so that each test will, in tum, exercise and
verify those portions of the processor logic to be used in each succeeding test. Therefore, they should be used
in order: Instruction test 1A, 2, 2A, 2B, Random JMP-JMS, Random JMP, Random ISZ, followed by the
peripheral MAINDEC programs.
If memory problems are suspected, and the system employs the Extended Memory MC-I 2 option, the standard

MAINDEC tests should be employed first and the problem extensively checked to be sure that timing and currents are correct; then the extended memory tests can be employed. Note that the 8-Mode diagnostics use less
addressing logic than the LINC-Mode diagnostics.
Teletype and peripheral equipment can be evaluated and checked by running the specific diagnostic program for
each item. Before attempting to exercise a peripheral with its specific diagnostic, a check of the IOP logic should
be made to verify pulse width, height, and timing.
2.5.5 TC12 Tape Subprocessor
Troubleshooting the tape subprocessor must begin at the operator's console. Using the DO switch, exercise all of
the tape instructions. Follow the tape state indicators and compare them with the tape flow diagram (TC 12-0-10).
Watch the tape movement and direction. Is it in accordance with the tape state indicators on the console? Review the problem repeatedly to be certain that the problem is understood and that you know what the tape subprocessor and tape transport are doing!
Tape Register Control Test MAINDEC-12-D3AD, Parts I and II, checks almost all of the tape logic, with the exception of the reader-writers. If a problem can be duplicated using this diagnostic, the scope loop option may be
useful.
If a problem in timing or data transfer seems to exist, programming a long read or write loop will give the most
stable scope trace. For example:

2-9

*4020
4020/0700
4021/l 000
4022/1020
4023/0001
4024/1140
4025/0021
4026/1460
4027/7777
4030/6020
4031/1020
4032/1000
4032/l 021
4034/6020

RDC
1000
LDAI
0001
ADM

/READ AND CHECK
/QN & BLOCK NUMBER
/INCR BN

SAEI
7777
JMP 20
LDAI
1000
STC I l
JMP24

/INITIALIZE LOC 21
/WHEN IT REACHES 7777

/RESTART

This routine reads contiguous blocks from 0 to 777, thus allowing time to check timing and data transfers before
turnaround.
2.S.6 TC12 Console Checks
Step

Procedure
Clear memory (using the FILL-STEP, AUTO, and RIGHT SWITCHES= 0000).

With all tape units set to OFF LINE, set MODE switch to LINC and depress
I/O PRESET.

Place 0700 in the LEFT SWITCHES, and 0000 in the RIGHT SWITCHES.

Depress DO.

Do the LEFT SWITCHES transfer to the IR?

Do the RUN and INT PAUSE lights glow?

Does the TAPE IR go to 000?

Does the IP (In Progress) light glow?

Set the following constants into the LEFT SWITCHES; depress I/O PRESET
and DO. Observe that all combinations of bits transfer to the TAPE IR.

0701(TAPEIR=001)

0702 (TAPE IR= 010)

0703 (TAPE IR= 011)

0704 (TAPE IR = l 00)

0705 (TAPE IR= 101)

0706 (TAPE IR= 110)

0707 (TAPE IR= 111)

Mount a marked tape on tape unit O; place 0700 in the LEFT SWITCHES;
0777 in the RIGHT SWITCHES; depress 1/0 PRESET.

(continued on next page) ·

2-10

Step
7

Procedure
Depress DO.

Does the tape begin to move backwards initially (left to right)?

Does the tape then reverse direction and clock into the SEARCH
mode? Inability to sense direction may be caused by loss of the
mark track, a bad direction flip-flop, or loss of block numbers. The
tape changing direction in random fashion generally indicates that
the block numbers are not being read correctly (i.e., bad mark track).

While in the SEARCH mode, does the MB = 0777? (This is the block
number from the RIGHT SWITCHES.) Does the IR= 0700?

At the end of the SEARCH mode, does the tape transport enter the
BLOCK mode?

At the completion of the instruction, does the MA = 43 77, indicating
correct address transfer and memory incrementation?

Does the IR clear to Os? (MB will equal data transferred from tape to
location 4377.) Does the TAPE INST= 000?

Does the AC= 7777 at the completion of the tape instruction?
AC =I= 7777 indicates a failure of the TAC-to-AC transfer. If the
tape instruction cycles from SEARCH to BLOCK to IDLE to SEARCH,
a bad checksum on the tape is indicated. Try using another block
number in RIGHT SWITCHES bits 03 through 11.

Set 0701 into the LEFT SWITCHES, set 7000 into the RIGHT SWITCHES,
and depress DO.

At the completion of the instruction, does the MA go to 7777?

Note the number in the MB and examine the location addressed by
the MA (=7777); this location should contain what was in the MB,
indicating proper data transfer.

Does the IR clear to 0000?

Clear memory; set 0705 into the LEFT SWITCHES, 7000 into the
RIGHT SWITCHES; and depress DO.
a.

Does the tape clock into SEARCH-BLOCK modes twice (once
for WRITE, once for CHECK)?

Does the MA count from 4000 to 0000? If so, this indicates
proper cycle break.

Does the AC set to 7777 at the end of the instruction, indicating
a good checksum?

Set 0701 into the LEFT SWITCHES, 7000 into the RIGHT SWITCHES.
Depress DO.
a.

Does the MA count to 7777?

Examine locations 4000 to 7777. Are they all Os?

Fill memory with 7777 and repeat Steps 10, 1Oa., and 1Ob.
Memory should still be all Os. Failure at this point indicates
either bad reader-writers or poor memory.

(continued on next page)

2-11

Step

Procedure

When tapes have been verified up to this point, execution of the RDC, WRC,
RCG and WRG instructions should be checked, using varied combinations of
the instructions with the I-bit both on, and off, and various quarter and block
numbers.
NOTE
Execution of a tape instruction with the I-bit on,
using the DO key, does not cause tape motion to
continue due to RUN being cleared.

Execute MAINDEC-l 2-D3DA-PB, TAPE EXERCISER, to confirm LINCtape
control reliability.

2.S.7 Logic Troubleshooting
Logic troubleshooting in the PDP-12 is best accomplished using the technique of "reverse signal tracing". That is,
when a malfunction has been isolated to a section of logic, some duplication of that type of failure using either the
DO-AUTO switch combination, a small program, or a scope loop option in a diagnostic MAINDEC should be performed. Then, by comparing the logic engineering drawings with the machine status, and tracing the faulty signal
back to the failing gate, that portion of logic which is causing the failure becomes evident.
NOTE
An unconnected input to a gate, if not tied to a terminator,
floats at approximately +2.0V.
Before attempting to troubleshoot the logic, make sure that proper and calibrated test equipment is available.
Always calibrate the vertical preamplifier and probes of the oscilloscope before using. Make certain that the
oscilloscope has a good ac ground, and keep the de ground from the probe as short as possible.
Use the oscilloscope to trace signal flow through the suspected logic element. Oscilloscope sweep can be synchronized by control pulses or by level transitions which are available at individual module terminals on the wiring
side of the logic. Care should be exercised when probing the logic to prevent shorting between pins. Shorting of
signal pins to power supply pins can result in damaged components. Within modules, unused gate inputs are held
at +3V.
WARNING
Standard safety practices should be observed when working with
energized equipment. Remember that peripherals are not always
connected to the mainframe power control and may be energized
when the PDP-12 is off.
2.S.8 Module (Circuit) Troubleshooting
Engineering schematic diagrams of each module are supplied with the PDP- I 2 System and should be referenced
for detailed circuit information. Copies of engineering schematic diagrams are contained in Volume III of this
Maintenance Manual.
Visually inspect the module on both the component side and the printed-wiring side to check for overheated or
broken components, etc. If this inspection fails to reveal any signs of trouble or fails to confirm a fault condition
observed, use the multimeter to measure resistance.
CAUTION
Do not use the lowest or highest resistance ranges of the multimeter when checking semiconductor devices. The X 10 range is
suggested. Failure to heed this warning may result in damage to
components.
2-12

Measure the forward and reverse resistance of diodes. Diodes should measure approximately 20 ohms forward
and more than 1000 ohms reverse. (Front-to-back ratio should always be greater than l 0 to 1.) If readin~ in
each direction are the same and no parallel circuit paths exist, replace the diode.
Measure in both directions the emitter-collector, collector-base, and emitter-base resistances to transistors. Short
circuits between collector and emitter or an open circuit in the base-emitter path cause most failures. A good
transistor indicates an open circuit in both directions between
collector and emitter. Normally 50 to I 00 ohms exist between
the emitter and the base, or between the collector and the base
in the forward direction, and an open circuit condition exists in
the reverse direction. To determine forward and reverse directions, consider a transistor as two diodes connected back to
back. In this analogy, PNP transistors would have cathodes connected together to form the base. and both the emitter and
collector would assume the function of an anode. In NPN
transistors, the base would be a common-anode connection;
and both the emitter and collector would be the cathode.

Multimeter polarity must be checked before measuring resistance because many meters apply a positive voltage to the
common lead when in the resistance mode.
Since integrated circuits contain complex circuits with only
the input, output, and power terminals available, static
multimeter testing is limited to continuity checks for shorts
between terminals. Integrated circuit checking is best done
under dynamic conditions and using a module extender to
make terminals readily accessible. Using PDP-12 engineering
drawin~ (Volume III) and the M-series module schematics
(Volume IV), an integrated circuit is located on a circuit
board in the following manner:

8 B

12-0133

Figure 2-1 IntegratM Circuit Location
Hold the module with the handle in your left hand
(the component side facing you). Integrated circuits are numbered starting at the contact end of
the board in the upper right corner; the numbers
increase toward the handle. When a row is complete,
the next integrated circuit is located in the next row
at the contact end of the board (refer to Figure 2-1 ).
The pins on each integrated circuit are located as
shown in Figure 2-2.

2.5 .9 Repairs and Replacements

7
12-0134

NOTE
DEC recommends replacing defective modules with
modules of known quality on a one-for-one basis
and returning the suspect module to a DEC field
office for subsequent repair and/or replacement. If,
however, for expediency, field repairs must be performed, it is imperative to take the following precautions.

2-13

Figure 2-2 Integrated Circuit
Pin Location - Top View

When soldering semiconductor devices (transistors, diodes, or rectifiers, any of which may be damaged easily by
heat, physical shock, or excessive electrical current), take the following special precautions:
a.

Use a heat sink, such as a pair of pliers, to grip the lead between the nearest joint and device
soldered.

Use a 6V iron with an isolation transformer. Use the smallest iron adequate for the work.
Use of an iron without an isolation transformer may result in excessive voltages present at
the iron tip.

Perform the soldering operation in the shortest possible time, to prevent damage to the component and delamination of the module-etched wiring.

Integrated circuits may be easily removed by using a solder puller to remove all excessive
solder from contacts. Then, by straightening the leads, lift the integrated circuit from its
terminal points. If it is not desirable to save the defective integrated circuit for test purposes, then the terminals may be cut at the integrated body and each terminal removed
from the board individually. Be sure to orient the new integrated circuit in the same
position as the removed one.
CAUTION
Never attempt to remove solder from terminal points by heating
and rapping modules against another surface. This practice usually
results in module or component damage. Always remove solder
with a solder-sucking tool.

When removing any part of the equipment for repair and replacement, make sure that all leads or wires which are
unsoldered, or otherwise disconnected, are legibly tagged or marked for identification with their respective terminals. Replace defective components with parts of equal or better quality and tolerance.
In all soldering and unsoldering operations in the repair and replacement of parts, avoid placing excessive solder
or flux on adjacent parts or service lines. When the repair has been completed, remove all excess flux by washing
junctions with a solvent such as trichlorethylene. Be very careful not to expose painted or plastic surfaces to this
solvent.
2.5 .10 Validation Tests
Always return repaired modules to the location from which they were taken. If a defective module is replaced
by a new one during a repair period, tag the defective module, noting the location it was taken from and the
nature of the failure. When repairs are complete, return the repaired module to its original location and determine
whether or not the repairs have corrected the problem.
To confirm the fact that repairs have been completed, run all tests which originally showed up the problem. If
modules were moved during the troubleshooting period, return them to their original positions before running the
validation tests.
Any time that a module is replaced by one from spares, return the module to its original location to confirm its
defectiveness before initiating a repair procedure.
2.5 .11 Log Book Recording
A log book is supplied with each PDP-12 System. Corrective maintenance is not complete until all activities are
recorded in the log book. Record all data, indicating the symptoms displayed by the fault, the method of fault
detection, the component at fault, and any comments which would be helpful in maintaining the equipment in
the future. The log should be maintained on a daily basis, recording all operator usage and preventive maintenance
results.
2-14

CHAPTER 3
ADJUSTMENTS

Adjustments of the PDP-12 should not be undertaken until it has been confirmed that a failure is due to
misalignment of one or more of the following adjustments rather than to a faulty component. Where pertinent,
Volume III system drawings will be referenced with the last three letters of the drawing designation enclosed in
parentheses.
NOTE
The measurements and adjustments in the following paragraphs
are analog in nature, and are not of the on-off, high-low, or twostate conditions. The values stated are nominal and may vary
up to ±10%, depending on the specific configuration of the
system, or the device being checked.
3.1 MEMORY CURRENT AND STROBE

Testing and adjusting of the PDP-12 memory section are accomplished by running the memory address tests and
memory checkerboard tests. Adjustment of the read/write currents may be necessary to tune the memory for
optimum performance. Paragraphs 3 .1.1 through 3 .1.5 provide the checks and adjustments that can be performed
in the field.
3.1.1 Initial Current Adjustments
Procedure

Step

Turn on the computer, but do not execute any programs.

Adjust the oscilloscope as follows:

Trigger: Channel 1 only

Mode: Channel 1

Channel 1: SV /Division

Set ground reference sweep on 1 cm above center horizontal
graticule (see Figure 3-1 ).

Sweep: 0.5 ms

Connect scope probe to Channel 1, location F2M2.

Adjust the rightmost trim pot (if there are two) on module G826, locations E2 and F2, for approximately -l 2V.
Turning the trimpot counterclockwise increases the voltage (refer to Paragraph 3.2.1 ).

3-1

Figure 3-1 Ground Reference

3.1.2 Initial Strobe Adjustment
Step

Procedure
Turn off the computer and remove power.

Remove module M360 at location El4 (MCT) and turn the potentiometer
fully ccw.

Tum the potentiometer CW five full turns.

Return the module to location El4.

The above action sets STROBE approximately. For further fine adjustment, see Paragraph 3.2.1.
3.1.3 Memory Strobe Adjustments
Step

Procedure
Load the RIM LOADER in core memory by use of the console keys and
switches as follows:
a.

Set starting address 7756 in the LEFT SWITCHES.

Set 6032 (first instruction) in the RIGHT SWITCHES.

Depress FILL, followed by FILL STEP.

Set the next instruction in the RIGHT SWITCHES.

Depress FILL STEP.

Repeat Steps Id. and le. until the program is loaded.

(continued on next page)

3-2

Step

Procedure

1 (cont)

RIM LOADER
Address

Instruction

7756
7757
7760
7761
7762
7763
7764
7765
7766
7767
7770
7771

/6032
/()031
/5357
/6036
/7106
/7006
/7510
/5357
/7006
/6031
/5367
/6034
/7420
/3776
/3376
/5356

7772

7773
7774
7775

KCC
KSF
JMP. -1
KRB
CLL RTL
RTL
SPA
JMP. -6
RTL
KSF
JMP . -1
KRS
SNL
DCA I. +3
DCA. +2
JMP. -17

/CLEAR AC & KBD FLAG
/SKIP ON KBD FLAG
/NOT UP; WAIT
/CLEAR AC, KBD, READER BUF-+-AC
/CLEAR LINK, ROTATE 2 LEFT
/ROTATE TWO LEFT (AC and LINK)
/LEADER CODE?
/YES, READ NEXT BYTE
/NO, ROTATE TWO LEFT (AC and LINK)
/SKIP ON KBD FLAG
/NOT UP; WAIT
/READER BUF-+-AC
/IS THIS AN ADDRESS WORD?
/NO, USE INDIRECT
/YES, SET UP ADDRESS
/JUMP BACK

Set 7756 in the LEFT SWITCHES.

Set 0000 in the RIGHT SWITCHES.

Insert the basic CHECKERBOARD LOW in the Teletype reader
(MAINDEC-08-Dl LI).

Turn the Teletype ON LINE.

Set the reader to START.

Set the MODE switch to 8 MODE.

Depress the 1/0 PRESET.

Depress the ST ART LS.

After the paper tape has been read in, halt the computer.

Set 0005 in the LEFT SWITCHES.

Set 0101 in the RIGHT SWITCHES.

Depress 1/0 PRESET: then START LS.

Set the oscilloscope as follows:
a.

Trigger: Channel 1 only

Mode: ALT

Sweep: 0.1 µs

Slope: Positive: Coupling: LF Reject; Source: Internal

On the scope, set the Channel 1 GND reference 1 cm above the
center graticule.

On the scope, set the Channel 2 GND reference 2 cm below the
center graticule.

. The oscilloscope should appear as shown in Figure 3-1.
(continued on next page)

3-3

Step

Procedure

Attach the Channel 1 scope probe to Bl6JI (CPTP START MEMORY H).

Attach the Channel 1 scope probe to El4S2 (MCT STROBE FIELD 0 H).

Set the leading edge of the MEM START (MCT) as shown in Figure 3-2. Adjust the STROBE approximately
550 ns after MEM START.

Figure 3-2 MEM START and STROBE

3.1.4 Final Current Adjustments
Step

Procedure
Perform the set-up procedure for the memory strobe (Steps 1 through 3 in
Paragraph 3.1.3).

The oscilloscope is set as follows:

Trigger: Channel 1 only

Mode: Channel 2 only

Channel 1: 2V /cm

Channel 2: 50 m V /cm

Channel 2 GND reference: 2 cm below center graticule (see
Figure 3-1)

Current probe terminator to 2 mA/mV

Sweep: 2 µs

Slope: Positive; Source: Internal

Attach the current probe to Channel 2.

Attach the Channel 1 scope probe to Bl6Jl (CPTP START MEMORY H).
(continued on next page)

3-4

Step

Procedure

Attach the current probe to the loop provided from Cl Kl to C7T2, with the
arrow toward C7T2.

Adjust rightmost trimpot R28 on module G826 (locations E2 and F2) until
the positive waveform is 320 mA +5%, as shown in Figure 3-3. (Turning the
potentiometer CW increases the current.)

At the scope, set the Channel 2 GND reference 2 cm above the center
graticule and observe the negative waveform. As shown in Figure 3-4, it
should be approximately 350 mA +5%.

Figure 3-3 Positive Memory Current

Figure 3-4 Negative Memory Current

3-5

3.1.5 Memory Margins and Final Strobe Adjustments
Step

Procedure
Repeat the set-up procedure for the memory strobe (Paragraph 3.1.3).

With the Memory Checkerboard Program properly running, the memory
margins and final strobe adjustments are made as follows:
a.

Monitor the strobe relationship to MEM START.

Slowly increase the STROBE until the program fails. Record this
reading.

Turn the potentiometer two turns in the opposite direction and
restart the program.

Slowly decrease the STROBE until the program fails again. Record
this value.

The final STROBE adjustment is D + I /2 (B-D). For example: if the bottom reading (2d.) was 400 ns, and the
top (2b.) was 500 ns, the STROBE setting would be approximately 450 ns after the MEM START.
If current is incorrect, bits may be picked up or lost. If STROBE is not correctly adjusted, whole words may be

lost. Reading may also produce all MB bits set when they should be cJeared.
3.2 POWER OK
The Regulator Control Module, G826 (location E and F02), may require adjusting if applying or removing primary
power causes the contents of memory to be destroyed or the RUN flip-flop to be erroneously cleared.
3.2. l Check Procedure

If the E02J2 output is +3V, the regulator control has detected a power failure on the +5 or -J 5V bus. Check the
+5 and -1 SV power supplies; if the outputs are within specification (sec Table 2-2), adjust the G826 Module as
directed in Paragraph 3.7.2.
NOTE
There are two types of G826 Modules. The revision H modules
employ one trimpot (located on the right) for setting memory
currents. The POWER OK adjustment is a single-turn potentiometer, located in the center of the module and requiring a
double extender card to permit adjustment. On later revision
K modules, the POWER OK adjustment (a 10-turn helipot),
is located between the module plastic handles, permitting adjustment without requiring the extender card.
3.2.2 Adjustment Procedure
While observing ~n oscilloscope or meter at E02J2 (POWER OK H}, turn the potentiometer CCW until the signal
goes high (+3V) ( MCT). Then slowly turn the potentiometer clockwise until the signal just goes low; continue a
few degrees (approximately one hour on a 12-hour dial) more for the single-tum revision H modules, or I /2 turn
more for the l 0-turn helipot revision K modules.
Run the Power On/Off MAIN DEC program to check the adjustment. Tap the module to determine if the potentiometer is stable. Apply a small daub of paint or nail polish to seal the setting of the pmentiometer.

3-6

If POWER OK becomes high, symptoms may include loss of the instruction and data fields, 0-+ contents of AC,
0-+ RUN flip-flop, l -+ 8 Mode and 1 -+ FETCH (i.e., 1/0 PRESET).
3.3 EXTENDED MEMORY MC12

If the MCI 2 Memory Extension Control (alone, or with the MM81-A and/or MM81-B options) is included in the
user's system, the following procedure should be performed as a part of the memory current and strobe adjustments.

3.3.1 Set-up and Adjustment Procedure
Step

Procedure
Repeat Steps l through 13 of the Memory Strobe Set-up Procedure
(Paragraph 3.1.3).

Be certain the Checkerboard Program operates properly in the lower memory.

Halt the Computer.

Load the following program, using the procedure specified in Step 1 of the
Memory Strobe Set-up Procedure:
7700/6201
7701/1670
7702/6211
7703/3670
7704/2270
7705/5300
7706/7402
7670/0000

CHANGE DATA FIELD TO 0
TAD INDIRECT lOC 0070
CHANGE DATA FIELD TO 1
DCA INDIRECT LOC 0070
INCREMENT LOC 0070
JMP. -5
HALT TRANSFER COMPLETE

Set 0005 in the RIGHT SWITCHES.

Set 0101 in the LEFT SWITCHES.

Set 1 in the INST FIELD.

Depress the START LEFT SWITCHES.

Connect the Channel 2 probe of the scope to El 5S2 (MCT STROBE FIELD l H).
NOTE
Do not depress the 1/0 PRESET.

The adjustment procedure is identical to Initial Current Adjustments and Final Current Adjustment Procedure
(Paragraphs 3.1.l and 3.1.4, respectively).
Upon completion of the Memory Adjustments, run the following MAINDECs (see Table 3-1 ). If a failure occurs,
tune memory to run these diagnostics by varying current and STROBE adjustments approximately ± 10%.

3-7

Table 3-1
Memory Diagnostics

Program

Function

MAINDEC

CBH

DEC-08-D 112-PM

Tests Stack 0 for noise at low end

CBL

DEC-08-D 1L1 -PM

Tests Stack 0 for noise at high end

ADDRSHI

DEC-08-D 1BZ-PM

Tests Stack 0 low end addressing

ADDRSLO

DEC-08-D 1B1-PM

Tests Stack 0 high end addressing

MEMDATA

DEC-12-D 1EA-PB

Test Stacks O+ 1 for random data
(see Writeup DEC-12-DlEA-D)

EXT CB

DEC-08-D 1DA-PB

Tests Stacks O+ 1 for noise

EXT AT

DEC-08-D 1HA-PB

Tests Stacks O+ 1 for addressing

JMPSELF

DEC-12-D 1BA-PB

Tests Stacks o+ 1 for address select speed

NOTE
PB - Paper-tape Binary
PM -·Paper-tape RIM
D -Document

3.4 TELETYPE CLOCK
Procedure

Step
Oscilloscope set-up:

Trigger: Normal

Mode: Channel 2 only

Sweep: 1.0 ms

Slope: Positive; Coupling: LF Reject; Source: Internal

Channel 2 GND reference: 2 cm below center graticule

Channel 2: 2V/cm

Connect the Channel 1 scope to N8R2 (TTO TTI CLOCK H).

Connect the Channel 2 scope probe to N8K2 (ITO CLOCK L).

Adjust the potentiometer on M452 L-J N8 for a frequency of 4.5 ms(TTO). Turning the potentiometer CCW
decreases the clock frequency. (Refer to Figure 3-5).
The 4.5 ms clock synchronizes the CP with the Teletype data transmission; thereby assuring that bits will not be
picked up or lost during transmission.
NOTE
Diagnostics, DEC-08-D2PE-PB (Teletype Test Part 1) and
DEC-08-D2QD-PB (Teletype Test Part 2) should be run to
check the Teletype. For more information, see Chapter S.

3-8

Figure 3-5 Teletype Clock (Sweep at .5 ms)

3.5 LINCtape
Paragraphs 3.5 through 3.7.2 provide the checks and adjustment procedures for the LINCtape control and tape
transports. Maintenance personnel must be thoroughly familiar with the LINCtape transports and associated control circuitry before attempting any maintenance checks or adjustments.

NOTE
Adjustments to the LINCtape are performed only after a
thorough cleaning of the tape guides and tape heads, thereby minimizing tape skew, a frequent source of LINCtape
problems.
3.5.1 Tape Timing Pulses
When the tape reaches its normal operating speed, tape timing pulses are generated and used for synchronization
of all LINCtape operations.

NOTE
This procedure is only a check to make certain that all the
tape timing pulses are present. Replacement of a module is
the only corrective adjustment.
Procedure

Step

Load the following program in core memory via the console keys and
switches:
a.

Set 0000 in the LEFT SWITCHES (0000 / = Starting Address).

Set 7300 in the RIGHT SWITCHES (7300 is the first instruction).

Depress FILL; then depress FILL STEP.

Set 7404 in the RIGHT SWITCHES (7404 is the next instruction).

Depress FILL STEP key.
(continued on next page)

3-9

Step
1 (cont)

Procedure

Repeat Steps Id. and le. until the program is loaded.
0000/7300
0001/7404
0002/6151
0003/5000

/CLEAR THE AC & LINK
RIGHT SWITCHES TO THE AC
TAPE MAINTENANCE IOT
JMP-3 AND REPEAT PROGRAM

Set 0000 in the LEFT SWITCHES.

Set 0040 in the RIGHT SWITCHES (simulates LTT TPO).

Set the MODE switch to 8 MODE, 1/0 PRESET.

Depress START LS (LEFT SWITCHES).

Set up the oscilloscope as follows:
a.

Trigger: Channel 1 only

Mode: Alternate

Slope: Negative; Source: Internal

Sweep: 0.5 µs

Channels 1 and 2: 2V/cm

Connect the Channel l scope probe to Cl 8Ml (LTT TPO L) and the
Channel 2 scope probe to C20Nl (LTT TP2 L).

As shown in Figure 3-6, LTT TPO should be a negative pulse, approximately
100 ns duration. LTT TP2 L should be a negative pulse, approximately
1 µsin duration ( LTT).

Set 0020 in the RIGHT SWITCHES (simulates LTT TP3).

Connect the Channel 1 scope probe to Cl8Nl (LTT TP3 L) and the Channel 2
scope probe to (LTT TP4 L) on Cl9Nl.

Set the scope sweep to 0.1 µs.

LTT TP3, as shown in Figure 3-7, should be a negative pulse of approximately
100 ns duration. LTT TP4 should be the same duration (LTT).

Figure 3-6 LTT TPO/TP2 Pulse Duration

3-10

Figure 3-7 LTT TP3/TP4 Pulse Duration

3.5.2 LTD XTLK Delay
The Cross Talk (XTLK) delay (LTD), when initialized, ensures that there will be only one TTO or TTI for a given
zero crossover on the tape (during read and write). XTLK is the most important TC12 adjustment and must be
correct.
Step

Procedure
Load the program as specified in the Set-up Procedure in Paragraph 3 .5 .1.

Set 0040 in the RIGHT SWITCHES (simulates TPO).

Set 0000 in the LEFT SWITCHES and depress the 8 MODE switch.

Depress I/O PRESET and START LS switches.

Set up the oscilloscope as follows:

Trigger: Channel 1 only

Mode: Alternate

Slope: Negative; Source: Internal

Sweep: 1 µs

Channel I GND reference at the center graticule

Channel 2 GND reference 3 cm below the center graticule

Connect the Channel l scope probe to C28Ul (LTT TPO L) and the Channel 2
scope probe to C28H2 (LTD XTLK H).

Adjust the right potentiometer of M307 (location C28) for 9 µs (LTD). Turning the potentiometer CCW increases the delay time, as shown in Figure 3-8.
The crosstalk delay ensures that only data on the tape is being read. If the delay is improperly adjusted, data may
not be read; if data is read, it may not be correct and the LINCtape control may not find the correct block, or
improperly write data onto tape.

3-11

- ---T----.--..
r

r
-- ----+-- ----1 -

I -tt++++<fi+t-H+H-+t++++t++'->-t+•++++-+++f-+H-H+++.j t++-+-+++tt-/-+t-+++-++-1-+f4+-+-+t+-++.+-<++->-+H++i-+H-++-H-+t1
r++i;

~-~'-__,-_-=LL=;=
12-0261

Figure 3-8 LTD XTLK Delay Time

3.5.3 LTD TIOK Delay
The TTOK (Tape Timing OK) monitors tape speed, inhibiting any data transfers (Read or Write) if proper tape
velocity over the read/write heads is not maintained.
The 48 µs TTOK delay ensures that tapes are moving at correct speed (within 50 percent) and that TPO and TP3
are being read. If the tape rocks in one position, or if IDLE and SEARCH are intennittent, the TTOK delay may
be suspected.
Procedure

Step

Halt the computer; turn off power.

Remove W603, at location Fl 6.

Restore power.

Load the program as directed in Paragraph 3 .5. I.

Set 0000 in the LEFT SWITCHES.

Set 0040 in the RIGHT SWITCHES (simulating LTT TPO).

Set the AUTO REST ART delay as follows:
a.

Set the COARSE selector to 3.

Set the FINE control to FAST.

Set SING STEP and START LS.

Depress AUTO and hold it down.

Depress CONT; then release the AUTO key.

Set the oscilloscope as follows:
a_

Trigger: Channel I only

Mode: Channel 2 only
(continued on next page)

J-12

Step

Procedure

11 (cont)

Slope: Negative; Source: Internal

Sweep: 5 µs

Channel 2 GND reference 1 cm below the center graticule

Sweep Mode: Normal

Connect the Channel 1 scope probe to C28Ul (LTT TPO L) and the Channel 2
scope probe to C28E2 (LTD TTOK L).

If this delay is set for 48 µs (LTD), refer to Step 16.

Adjust the left potentiometer of M307 (location C28) for 48 µs. Turning
the potentiometer CCW increases the delay.

Refer to Figure 3-9.

Halt the computer, remove power.

Reinstall the W603, at location Fl 6.

Figure 3-9 LTD TTOK Delay

3.5.4 LTD TAPE FAIL Delay
A Tape Fail Delay signal results in a tape motion stop if:
a.

The tape transport programmed to run is not selected,

The tape timing (TTO) pulses are lost.

The delay is set up as follows:
Procedure

Step

Turn off the computer power and remove M304 Module at location Cl 7.

Restore power to the computer.
(continued on next page)

3-13

Step

Procedure

Load the program as directed in Paragraph 3.5.l.

Set 0000 in the LEFT SWITCHES.

Set 0040 in the RIGHT SWITCHES (simulating LTT TPO).

Set the AUTO RESTART delay as follows:
a.

Set COARSE control to position 2.

Set FINE control to SLOW.

Set SING STEP; then set START LS.

Depress AUTO and hold it down.

Depress CONT; then release AUTO.

Set the oscilloscope as follows:

Trigger: Channel l only

Mode: Channel 2 only

Sweep: 50 ms

Slope: Negative; Source: Internal

Set Channel 2 reference GND to center graticule

Set Channels I and 2 to 2V /cm

Sweep Mode: Normal

Connect Channel l scope probe to C30Ul (LTT TPO L).

Connect Channel 2 scope probe to C30F2 (LTD TAPE FAIL L) (LTD).

If the delay is 300 ms, refer to Step 16.

Slowly increj:lse the FINE AUTO RESTART delay until the trace is stable.
Increasing the AUTO RESTART delay past 300 ms inhibits the delay. Adjust the right potentiometer of the M307 Module, at C30, for 300 ms.
Turning the potentiometer CCW increases the delay.

Refer to Figure 3-10.

Halt the computer: remove power.

Reinstall the M304 Module at location Cl 7.

3.5.5 LTD ACIP Delay
The ACIP (ACceleration In Progress) delay signal inhibits tape timing during any change in tape direction (starting
or tape turn-around).
If the ACIP delay is not adjusted correctly it may result in the inability to read blocks. or in erratic tape motion.

3-14

Figure 3-10 LTD Tape Fail Delay

Step

Procedure
Load the following program:
0000/7300
0001/1006
0002/6152
0003/7006
0004/6152
0005/5000
0006/0020

CLEAR AC & LINK
TAD K20 AC = 0020
TAPE MAINT. IOT (set motion backward)
ROTATE 2 LEFT, AC= 0100
TAPE MAINT. IOT (set motion reverse)
JMP . -5 & REPEAT
K20

Set 0000 in RIGHT SWITCHES.

Set the AUTO RESTART delay as follows:
a.

Set the COARSE selector to 2.

Set the FINE control to SLOW.

Set the SING STEP, MODE switch to 8 MODE and depress 1/0 PRESET.

Depress START LS; depress and hold AUTO key.

Depress CONT; then release AUTO.

Set the oscilloscope as follows:

Trigger: Channel 1 only

Mode: Channel 2 only

Sweep: 20 ms

Slope: Negative; Coupling: LF Reject; Source: Internal

Channel GND reference 1 cm below the center graticule

Channels 1 and 2 to 2V /cm

Connect Channel 1 scope probe to C30K2 (LMU DIRECTION 0 L).
(continued on next page)
3-15

Step

Procedure

Connect Channel 2 scope probe to C3/E2 (LTD ACIP L).

Adjust the left potentiometer of the M307 Module, at location C30 (LTD),
for a 180-ms delay. Turning the potentiometer CCW decreases the delay.

Refer to Figure 3-11.

Figure 3-11 LTD ACIP Delay

3.5 .6 Mark Clock Adjustment
The mark clock ( LTS) establishes tape timing and mark track signals when formatting virgin tape.

If the MARK flip-flop period is longer than 7.5 µs ± 5 percent when virgin tape is marked, the marking process
will not finish before end-of-tape is reached.
If the MARK flip-flop duration is shorter than 7 .5 µs, data will not transfer to virgin tape correctly, i.e., running
a PIP copy program.
CAUTION
Remove all tapes before starting this adjustment.
Procedure

Step

Halt the computer. Turn off the power.
2

Install a jumper from E21K2 to E21 Tl.

Turn on the computer.

Set up the oscilloscope as follows:
a.

Trigger: Channel 1 only

Mode: Channel 1 only

Sweep: 1 µs
(continued on next page)

3-16

Step
4 (cont)

Procedure
d.

Slope: Positive; Source: Internal

Channel 1: 2V /cm

GND reference of Channel 1 at the center graticule

Connect Channel 1 scope probe to E2 l D2.

Adjust the M401 Module at location E2 l for 7 .5 µs as shown in Figure 3-12.
Turning the potentiometer CCW increases the clock frequency.

Turn off the power and remove the jumper installed in Step 2 of the Set-up
Procedure.

Figure 3-1 2 Mark Clock

NOTE
The diagnostics TC 12-1 and TC 12-11 should be used as a final
test on the TC12 LINCtape Control.
3.6 TUSS TAPE TRANSPORT
NOTE
Before any mechanical adjustments are performed, user maintenance personnel are directed to check the model of the tape
transport provided with their system. Some PDP-12 systems
are equipped with the TUSS tape transports; other PDP-12
systems employ the TU56 transport. Users are directed to the
TUSS or TU56 Maintenance Manuals for complete maintenance information concerning the tape transports.
Each of the LINCtape transports contains a pair of tape reel hubs driven by an induction motor. The tape motors
are relatively high torque and low inertia, which allows the tape to be started and stopped quickly. Correct
operation of the tape system requires the tape to be rapidly started and stopped, without its being lifted off the
heads. Tape lifting can be a frequent source of problems for the LINCtape system, and also one of the most
difficult to discern.
3-17

The following mechanical adjustment procedures (Paragraphs 3.6.l through 3.6.3) provide those mechanical
adjustments that can be performed by competent field maintenance personnel.
The hub shaft assembly and motor should be adjusted so that they spin freely, with no appreciable amount of
friction, do not bind, and are mechanically quiet when operating.
3.6.1 TUSS Brake Adjustment
Step

Procedure
Turn off the power to the transport that is to be adjusted. Tapes should
not be mounted on the transports.

Slide the transport fully forward.

Remove the 115-Vac line cord from the transport.

NOTE
The brake shoes are located on the motor shafts as
shown in Figure 3-13. The brake shoes follow the
rotation of the motor shaft (hubs).

ALLEN SET
SCREWS

BRAKE SHOE

.004-INCH
FEELER GAUGE

Figure 3-13 TU55 Brake Adjustment

(continued on next page)

3-18

Step

Procedure

Insert a .004-in. feeler gauge between the brake shoe and brake surface.

Adjust the brake for proper clearance by loosening the two Allen setscrews
on the brake shoe and moving the brake in and out along the shaft.

After the adjustment is made and the Allen setscrews arc secured, rotate the
hub several revolutions by hand to be certain that there is no binding and that
the motor turns freely.

Set the FUNCTION control to LOCAL and pulse the DIRECTION switch. A
properly adjusted brake should produce a minimum of "clicking."

Repeat this procedure for each hub on all the TU55 transports.

Reinstall 115-Vac line cord.

3.6.2 TUSS Torque Adjustments
The following equipment is required:
a.

VOM or VTVM with a set of insulated clip leads

Small long-shaft ( 6-in.) screwdriver

Oscilloscope

Stop-Torque Adjustment

Step

Procedure
Line voltage (ac) to TU55 on.

Scratch tape installed on both hubs.

Brake gap set as described in Paragraph 3.6. l.

Switch the unit to LOCAL.

Connect the VOM to the tab terminals of Module G850 at location A 12
(right motor) as shown in Figure 3-14. Expect a reading of approximately
60 Vac.

Depress FWD-+ switch and release.

Adjust trimpot nearer the G850 handle for meter reading of 50 Vac.

Connect the VOM to the terminals of Module G850 in location A 11 (left
motor) as shown in Figure 3-14.

Depress the REV~ switch and release.

Adjust the trimpot nearer the G850 handle for a meter reading of 60 Vac.

3-19

COMMON (GND) TERMINAL

LOCATION A12
RIGHT MOTOR
LOCATION A11
LEFT MOTOR

LEFT MOTOR TERMINAL

RIGHT MOTOR TERMINAL

Figure 3-14 TU55 Torque Adjustment Tabs

Trailing Torque Adjustments
Step

Procedure
Connect the VOM to tab terminals of the G850 Module in location Al 2
(right motor). Expect 85 Vac.

Rewind the scratch tape so that the right reel is nearly full.

Depress and hold the REV ~ switch so that the tape is winding onto the left
reel as the following adjustment is made.

Adjust the potentiometer farthest from the G850 Module handle. Make certain
that the tape is still in motion while the adjustment is made. Adjust for 85 Vac.

Connect the VOM to the tabs of the G850 Module in location All (left motor).

Wind the scratch tape so that the left reel is nearly full of tape.

Depress and hold the FWD-+ switch so that the tape is winding onto the right
reel as this adjustment is made.

Adjust the potentiometer farthest from the G850 Module handle for a meter
reading of 85 Vac (Figure 3-15). Make certain that the tape is still in motion
during the adjustment.

3-20

FRONT OF TAPE TRANSPORT

85 VAC
ADJUST

60VAC
ADJUST

R303 MODULE TRIMPOT R9
DELAY ADJUST

Figure 3-15 TU 5 5 Stop Delay Adjustment

Stop Delay Adjustment
Step

Procedure
Switch the tape unit to LOCAL.

Set the oscilloscope as follows:
a.

Trigger: Channel 1

Mode: Channel l

Channel 1: 2V /cm

Sweep: 10 ms

Connect the scope probe to A04D.

Depress and release FWD~ switch.

Adjust potentiometer R303 for approximately 80 ms delay, as shown in
Figure 3-15, or until tape snapping is minimal.

3.6.3 TU55 Transport Head Replacement and Adjustment Procedures
These procedures outline the steps necessary to effect a field (on-site) replacement and/or alignment of the
read/write tape head on the TU55 Tape Transport. The need for adjustment is indicated when the following
specifications are exceeded:

3-21

The tape head is to be vertically aligned between the tape guides, projecting I /8 in. above the
guide edges.

The maximum amount of tape skew should not exceed± 3 µs.

/lead Removal
Procedure

Step

At the tape transport control panel, set the REMOTE/OFF/LOCAL switch to
the OFF position and remove ac power to the computer.

Disconnect the ribbon connector from the G85 I Relay Board.

Remove one of the two head clamps; loosen the other clamp.

Remove the tape head from the transport.

Head Installation
Procedure

Step

Replace the tape head with a new assembly, reversing Steps 3 and 4 above.

Secure the mounting clamps.

While tightening the clamps, make certain that the tape head is vertically
aligned between the tape guides and that it is projecting I /8 in. above the
tape guides.
NOTE
This procedure applies only to GJM heads or
Western magnetic tape heads. Set the selector
switch on the skew checker to GJM. (Refer to
Figure 3-16).

Head Skew Adjustment
Procedure

Step

Mount a DEC-certified master skew tape on the transport.

Connect the skew checker to the tape head ribbon connector and the tape
transport de supply terminals.

Pin A of the checker connector should mate with the pin
closest to the larger end of the tape head connector.

In most installations, the power wiring is color-coded to
correspond with the TUSS wiring. In some transports,
however. the+ 1OV lead may be read; in this case, this
will be a green wire connection to the checker.

Connect the oscilloscope probe to the point marked SKEW.
Connect the scope ground to the point marked GND (black).
Adjust the scope for a 1-µs/cm horizontal sweep and a t V/cm
vertical sensitivity.

(continued on next page)

3-22

SKEW
B

BLK

SHIELD

~--__.~C>--+-----------o---0~
H,J

--o---BRUSH

F,P

R111

WHT

BLU

- -o- - - - - .. - - __.
GJM

BRUSH

GJM

c
RED
12·0127

Figure 3-16 Skew Checker Schematic Diagram

Step
2 (cont)

Procedure
d.

Restore ac power to the computer and place the tape transport
REMOTE/OFF/LOCAL switch to the LOCAL position. While
observing the oscilloscope, move the master skew tape back and
forth across the tape head. Note that the output of the skew
checker (as presented on the scope) does not exceed ±3 µ.s.
(Refer to Figure 3-1 7).

If the skew appears to be on the edge of the tape guides or
slightly out of specification, some skew adjustment can be
made by moving the tape head slightly to one side or the
other and/or alternately loosening and retightening the
mounting screws of the tape head clamps. In most cases,
this action changes the skew ±1 µ.s. If a large amount of
skew is present, shimming of the tape head becomes
necessary.

Shim the Tape Head

To determine the direction in which to shim, lightly press
against the moving tape on either side of the head. If skew
is reduced when pressing at the right side of the head, shim
the right rail of the head block. If the skew is reduced
when pressing at the left side of the head, remove the shim
stock from the right rail. Use 1/2-mil shim stock (available
as "Scotch Tape Marker"), and shim only the right rail of
the head.
(continued on next page)
3-23

NOTE: A RAGGED TRAIL.ING EDGE
IS CAUSED BY TAPE BOUNCE
12-0126

Figure 3-17 Skew Checker Output

Procedure

Step
3 (cont)

After shimming the head, realign the tape head (as directed in
Steps 2 and 3 of Paragraph 3 .6.3, Head Installation) and recheck the skew. The skew must be less than 3 µ.sin both
directions.

3.7 TU56 TAPE TRANSPORT
Complete service and adjustment and other maintenance information can be found in the TU56 Maintenance
Manual DEC-00-HRTA-D. For convenience of maintenance personnel, the TUS6 Brake and Oscillator Adjustments are provided below:
3.7.1 TU56 Brake Adjustment

Step

Procedure
Mount a scratch tape on the transport.

Tilt the tape transport front panel forward.

Set the oscilloscope as follows:

Trigger: Normal

Mode: Channel 1

Sweep: 10 ms

Slope: Positive; Coupling: LF Reject; Source: Internal

Trace for Channel 1 GND reference adjusted on the center
horizontal graticule

Set Channel 1 to 2V Icm
(continued on next page)
3-24

Step

Procedure

Connect the Channel 1 scope probe to B08F2. (See drawing
D-BS-TUS 6-0-TLD).

Enter the following routine:
4020/0703
4021/0300
4020/6020
I/O PRESET
START 20
Unit Set to UNIT 0.

MTB
Block 300
JMP .-2

The above routine will cause the tape unit to oscillate (or rock) between two
blocks, causing the brake delay to be repeatedly displayed (about 3-times/s)
on the scope.
This rocking action will permit the viewer to conclude the brake delay adjustment procedure without repeatedly advancing and rewinding the tape
hubs manually.
6

To adjust the left hub brake delay, tum the upper potentiometer for a delay
of 80 ms (see Figure 3-18).

Connect the scope probe (Channel 1) to B08T2.

To adjust the right hub brake delay, turn the lower potentiometer for a
delay of 80 ms (see Figure 3-18).

Repeat the procedure for each pair of tape hubs.

Figure 3-18 8_0 ms Brake Delay Adjustment

3-25

3. 7 .2 Oscillator Adjustment
Step

Procedure

Set the oscilloscope as follows:

Trigger: Normal

Mode: Channel 1

Sweep: 5 ms

Slope: Positive; Coupling: LF Reject; Source: Internal

Channel 1 GND reference adjusted on the center horizontal
graticule

Channel 1 to 2V /cm

Connect the scope probe to A03M2 of the TU56 transport logic

Adjust the potentiometer to 25 ms as shown in Figure 3-19.

Figure 3-19 25 ms Oscillator Adjustment

3.8 ANALOG (AD12) AND DISPLAY (VR12, VC12 or VR14, VC14)
Paragraph 3 .8 .1 provides the checks and adjustments to be performed in the field. Included are the A/D circuits
(preamps and optional multiplexer channels) and the VRI 2 display and control adjustment procedures. The information contained in this adjustment manual provides for only those adjustments which are to be performed to
the A/D circuits and the video display circuits jointly. Complete maintenance information for the VRl 2 display
system is available in the VRJ 2 Point Plot Display Maintenance Manual (DEC-CR-H6AA-D) and for the VR 14
display in the VR14 CRT Display User'sManual(DEC-12-HRZA-D).

3-26

3.8. I Digital-to-Analog Adjustment Procedure (A6 IS)

Step

Procedure
Load the following program:
DISPLAY A POINT & INCREMENT
JMP. -1 & REPEAT

4020/0162
4021/6020

Set the RIGHT ai:id LEFT SWITCHES to 0.

Set the MODE switch to LINC; depress the 1/0 PRESET; depress ST 20.

Turn on the VR 12 and set the brightness potentiometer approximately 3/4
of a turn from off.

Set the CHANNEL SELECT to 1 and 2.

Depress ST ART 20.

A straight line will be displayed. If the line is of uniform brightness and continues from one side of the screen to the other without gaps, refer to Step 2
of this procedure. If the line displayed appears as E of Figure 3-20, refer to
Step 1 of Adjustment Procedure, Paragraph 3.8.2.

A, 16 SEGMENT

B, 8 SEGMENT

-- -- -- -- -- -- -

C, 4 SEGMENT

0, 2 SEGMENT

E, OPTIMUM DISPLAY

12-0086

Figure 3-20 D/ A Line Display

The four most significant bits of Module A6 l 5, Digital-to-Analog Converter, are adjustable (R37 through R40 in
Figure 3-21 ); bit 3 being the most significant, and bit 6 being the least significant. A misadjusted A615 displays
a line either with gaps or overlays, or a combination of both. Figure 3-20 provides an example of all four significant bits being set too short. Data bit 3, being too short, divides the line into two equal halves (D). Data bit 5
divides the line into 8 segments (B) and, likewise, bit 6 divides the line into 16 equal segments (A).

3-27

GAIN ADJ
OFFSET ADJ
CHAN 11

GAIN ADJ
OFFSET ADJ
CHAN10

CHAN13

CHAN12

CHAN15

CHAN14

CHAN17

CHAN16
FINE ADJ

FACTORY
ADJUSTMENTS
ONLY

COARSE ADJ

R40

R39

R38

R37

Figure 3-21 Sample and Hold Adjustments

Step

Procedure
The A615 is adjusted, starting with bit 6, the least significant bit, and adjusting toward the most significant bit, bit 3. Note the 16 segments of A
of Figure 3-20. Adjust potentiometer R37 of Module A6 l 5, locations
E and F37 (bottom of A6 l 5), until only eight segments are displayed as
shown in B of Figure 3-20.

Adjust potentiometer R38 until only four segments are displayed, as shown
in C of Figure 3-20.

Adjust potentiometer R39 until only two segments are displayed, as shown
in D of Figure 3-20.

Adjust potentiometer R40 until the line is complete (straight and unbroken).
Potentiometers R39, R38, and R37 may require minor touching up, as some
interaction is possible; the overlays are adjusted in the same manner except
that the settings must be decreased.

After setting Module A6 l 5 at locations E and F3 7, halt the computer and
turn off the power. Swap Module A6 l 5 in locations E and F3 7 with the
Module A6 l 5 in locations E and F3 6. Repeat the entire A6 l 5 Adjustment
Procedure.

3-28

3.8.2 VR12 Size and Position Adjustments
Step

Procedure
Size can be adjusted to the user's requirements by adjusting the X- and YPosition potentiometers.

On Module M7 l l (locations C and D37), set the three switches for normal
operation as listed below:

Set PRR switch to FAST.

Set WIDTH switch to MIN.

Set POL switch to - .

3.8.3 Brightness and Brightness Preset Adjustment
Load the display test (using the LAP6-DIAL MAINTENANCE tape) as follows:
Procedure

Step

Mount a LAP6-DIAL MAINTENANCE tape on any tape transport.

WRITE ENABLE on, turn the thumbwheel switch to 0, REMOTE depressed.

Set 0701 in the LEFT SWITCHES (RCG).

Set 7300 in the RIGHT SWITCHES (all other switches are set to 0).

Set MODE switch to LINC; depress I/O PRESET.

Depress DO key; when tape motion stops, depress I/O PRESET; then
ST ART 20. (At this point, a I should be displayed at the left of the
screen. Directly across from it, a bar (-) will also be displayed. If
this does not occur, check to be sure that CHANNEL 1 is selected and
the BRIGHTNESS potentiometer is fully CW.)

On the Teletype, type LINE FEED (an arrow will appear at the bottom

left of the screen).
8

Type LO (space) DISPTST; then 0 (Example: >LO DISPTST, > 0).

Type a carriage return.

Depress I/O PRESET to LINC mode; depress START 20. The first display is a full-screen grid pattern.

When the grid pattern appears on the screen, at the Teletype, type an F.
(This action freezes the pattern being displayed.)
NOTE
For a more detailed explanation, refer to the
DISPLAY TEST write-up (MAINDEC-12-D6BA-D).

Set the CHANNEL SELECT control to 1 and 2.

Set the BRIGHTNESS control fully CW.

Remove the retaining pin, at the rear of the computer.

Slowly slide the YR 12 or YR 14 video display unit forward until it stops.
(The BRIGHTNESS PRESET adjustment is located on the top of the
unit.)
(continued on next page)

3-29

Step

Procedure

Adjust the BRIGHTNESS PRESET control for the highest brightness level
level possible that does not cause blooming of the presentation.
CAUTION
Exces.sive brightness or blooming can shorten the
life of the CRT.

The FOCUS adjustment is located next to the BRIGHTNESS PRESET control, and should be adjusted for the
sharpest overall presentation.
3.8.4 Deflection Amplifier Quiescent Current Adjustment (VR12)
Step

Procedure
Load the display test as specified in the adjustment procedure, but do not
freeze the pattern. The test cycles through three different display patterns.

When the X pattern appears on the display, type an F to freeze the pattern.

Set the potentiometers on both G9 l 2 Deflection Amplifiers fully CCW by
inserting a screwdriver with an insulated shaft into the hole on the heat sink.

Adjust the potentiometer for straight lines at the crossover points and for
a minimum amount of noise.

3.8.5 Analog-to-Digital Adjustment Procedure
Step

Procedure
Mount a LAP6-DIAL MAINTENANCE tape on the right hub of any
available LINCtape transport.

On the transport, set WRITE ENABLE on, turn the thumbwheel switch to
0, and REMOTE to on.

Set 0701 in the LEFT SWITCHES (RCG).

Set 7300 in the RIGHT SWITCHES.

Set all other switches to 0.

Set the MODE switch to LINC and depress 1/0 PRESET and DO switch.
When the tape motion stops, proceed to next step.

Depress START 20. (At this point, a 1 is displayed to the left of the
screen. A program may be in the LAP6-DIAL work area; if this is true,
the last number of the program is displayed at the left of the screen.)

At the Teletype, type a LINE FEED. An arrow will be displayed at
the bottom left of the screen.

After the arrow appears, type LOADTST,O then RETURN. The A/D TEST
is a self-starting program.

Turn knobs 00-07 fully CW. Channels 00 through 07 should read +777 8
(see Figure 3-22).

(continued on Page 3-32)

3-30

Figure 3-22 A-to-D Display

Step

Procedure

Note the starting position of knob 00. Tum the potentiometer slowly CCW,
monitoring Channel 00 on the screen until it reads +776 8 . The change must
occur 3/4 to 1-1/2 turns from the full CW position. Repeat this procedure
with the potentiometer set fully CCW. If, by slowly turning knob 0, the
least significant number can be made to hold solidly, proceed. But, if both
top(+) and bottom(-) are within the ranges specified, refer to the adjustment
procedure for the external Channels I 0 through 17. If the above test fails
(potentiometers fail to be within the above limits), refer to the Sample and
Hold Adjustment Procedure.

3.8.6 Sample and Hold Adjustment Procedure (A404)
CAUTION
Do not adjust any other controls except those specifically mentioned in Paragraph 3.8.7 and shown in Figure 3-21. If compensating trimpots located on Module A404 are disturbed, the
module must be returned to DEC for proper calibration.
NOTE
This adjustment affects all the external analog channels.
Step

Procedure
Load the A/D TEST as specified in Steps I through 9 of the Set-up Procedure, Paragraph 3.8.5.

After making certain that the A/D TEST is running properly. halt the
computer and tum off the power.

Remove Module A214 at location E33.

Install a jumper from D32R2 to D32F2.

Turn on the computer and depress the 1/0 PRESET.

Depress START 20. This should restart the A/D TEST.

While monitoring Channel 17, adjust the COARSE ADJ (see Figure 3-21)
Module A404 (locations E and F34) until Channel 17 displays 000 (see
Figure 3-21 ). Then adjust the FINE ADJ until the sign of the Channel 17
000 display oscillates between+ and - . This oscillation indicates proper
adjustment.

Halt the computer and remove the power.

Remove the jumper installed in Step 4 of the Set-up Procedure, above.

Proceed to the External Analog Channel Adjustment Procedure.

3.8.7 External Analog Channel Adjustment Procedure
To perform the following procedure, use a precision de mV standard, or equivalent (Electronic Development
Corp. Model MV-1005 ). and a standard input jack.

3-32

Step

Procedure
Load the A/D TEST as outlined in Steps 1 through 9 of the Set-up
Procedure, Paragraph 3.8.5.

Allow the voltage source five min. to warm up.

Connect the input cable to the output voltage terminals of the voltage source.

Set the output polarity switch to 0.

Monitor Channel 10, and adjust the right OFFSET potentiometer of Module
A214, at location E30, for a -000. Turning the trimpot (shown in Figure 3-21)
CCW increases the number.

Set the EDC (m V standard) for 0.9850.

Set the OUTPUT selector to+.

Adjust the right GAIN potentiometer for a reading of +776 8 ; turning the
potentiometer CW decreases the number.

Set the OUTPUT selector to - .

This value should be -776. If it is not, adjust the OFFSET until the+
and - values are equal. The GAIN should be adjusted for a stable reading
of+ and -7768 . The optimum zero value should be an oscillating+ - sign.

Set the EDC for 0.995V.

If the GAIN is properly adjusted, the + and - values will equal 777 8 •

Repeat the above procedure for the remaining channels.
Location

Left Potentiometers

Right Potentiometers

E30
E31
E32
E33

Channel 11
Channel 13
Channel 15
Channel 17

Channel 10
Channel 12
Channel 14
Channel 16

3.9 EXTENDED ANALOG(AG12, AM12)
3.9.1 Set-up Procedure
Channels 20 through 37 require an extra panel mounted on the bottom left of the PDP-12 Data Terminal Panel.
The cables plug into the following locations:
Channels

Location

20 through 27
20 through 37

F31
F30

The conversion box used to adjust these channels contains a cable with a G783 Connector mounted on one end,
and a 8-position (Channel 0 through 7) potentiometer connected at the other end. An Amphenol Jack leads to
the proper receptacles on the Data Terminal Panel from this 8-channel potentiometer. The procedure in Section
3.8.7 is used with the following addition: SENSE SWITCHES set to 00=1; Channels 20 through 37 will be displayed.

3-33

3.9.2 Adjustment Procedure
Procedure

Step

Monitor Channel 20 by plugging the cables for the conversion box into F3 l
and setting the 8-position potentiometer to Channel 0 (see Table 3-2).

The EDC setting and the adjustment for Channels 20 through 27 remain the
same as for I 0 through I 7.

To adjust Channels 30 through 37, insert the G783 cables from the conversion
box into slot F30, and repeat the procedure as outlined in Paragraphs 3.9.2
and 3.8.7.
Table 3-2
Monitor Table for Channels 20 through 37
Channels

Switch Setting

20 and 30
21 and 31
22 and 32
23 and 33
24 and 34
25 and 35
26 and 36
27 and 37

0
1
2
3
4
5
6
7

3-34

CHAPTER 4
FIELD INSTALLATION AND
CHECKOUT OF PREWIRED OPTIONS

Table 4-l contains a list of the prewired options which are discussed in this chapter.
Table 4-1
Prewired Options
Name

Type
AD12
AG12
AM12
DM12
DP12-A
DP12-E
DR12
KE12
KF12-B
KP12
KT12
KW12-A
KW12-B
KW12-C
MC12
TC12
TC12-F
TUSS
TU56
VC12 or VC14
VR12 or VR14
XY12
503

A-D Control
Preamplifier
Expanded Multiplexer
Data Break Multiplexer for KF 12-B
TTY Dataphone
TTY Dataphone (EEA-level)
Relays and Control
Extended Arithmetic Element
Multi-Level Automatic Priority Interrupt
Power Fail Restart
Time-Sharing Option
Real Time Clock
Simple Clock (limited frequency range)
Simple Clock (no frequency range)
Memory Extension Control
MAGtape Control
Extended Tape Control
Single Unit DECtape
Double Unit DECtape
Scope Control
Scope
Incremental Plotter
Scope

4.1 UNPACKING
When unpacking any prewired options, the following procedure should be used.
Procedure

Step

Unpack the kit and inspect it for any shipping damage.
2

Compare the kit contents with the packing list enclosed in the package.
Notify the DEC Sales Office if any discrepancy is noted.

4-1

4.2 INSTALLATION
When installing prewired options, the general procedure below is used.
CAUTION
Remove power before installing any prewired options, to prevent possible circuit damage to the modules, panels, and units.
Installation procedures should be performed by qualified service personnel only.
WARNING
High voltages are present within the equipment and are potentially dangerous. All safety precautions must be observed.
Procedure

Step

Before installing any option in the field, remove power from the PDP-12.

-Ensure that the CP and memory are at the ECO (Engineering Change Order)
level required for the proper operation of the option (refer to the DEC ECO
Log).

Prior to installation, run all of the appropriate MAINDECs listed below for
the option(s) to be installed (Table 4-2).

Install the modules and cables for the option as listed in Table 4-3.
Table 4-2
Option MAINDECs Checklist

Option
AD12

Pre-Diagnostic Check

Time

CPTS3

5 min

AM12

INST ST

5 min

DP12-A

2min

CPTS3

ITYl and 2

2min
N/A

DR12

2A
CPTS3
INSTST

5 min
5 min
5 min

KE12

All diagnostics applicable to system configuration

2 min each

KF12-B

All diagnostics applicable to system configuration

2 min each

KP12

Memory ON/OFF

N/A

KT12

All diagnostics applicable to system configuration

Time is test-dependent

KW12-A

2 min

KW12-B

2 min

KW12-C

2min

AG12

DP12-B

(continued on next page)

4-2

Table 4-2 (Cont)
Option MAINDECs Checklist
Option

Pre-Diagnostics Check

Time

MC12

CBL
CBH
ADDRSLO
ADDRSHI
FLTIO
JMPSLF

S min
S min
S min
S min
S min
S min

TC12

All tests applicable to PDP-12 configuration

Time is test-dependent

TC12-F

2A
CPTS2
CPTS3
TC12-1
TC12-2
MARK12
Tape Data II (Tape Exercisor)
PIP COPY
(UNIT 0 ~ UNIT 1)

2 min
2 min
2 min
5 min
S min
As Required
10 min
As Required

TUSS

Power Checks

As Required

TUS6

Power Checks

As Required

VC12 or
VC14

All tests applicable to PDP- I 2 configuration

N/A

XY12

2A
2B
CPTST
CPTS2
CPTS3

2min
2 min
2 min
S min
S min

Table 4-3
Option Module and Cable List
Note

Location

Option

Module

ADI2 1 ·

A214 (4-ea)
Al31 (2-ea)
A215
A404
A81 l
M760
G783
G783

Preamplifier
Multiplexer
Filter
Sample & Hold
A/D Converter
Control
Analog Cable
Relay Cable

E30,E31,E32,E33
D32, D33
D34
E-F34
C-D35
C36
F33
F32

AG12 2

A214 (8-ea)

Preamplifier

G783
G783

Channels 30-37
Channels 20-2 7

E26,E27,E28,E29,F26,
F27,F28,F29
F30
F31

Notes:

1. Panel AD12 is shipped with both the AD12 and DR12.

2; The AG 12 is a separate panel.

(continued on next page)
4-3

Table 4-3 (Cont)
Option Module and Cable List
Option

Location

Note

Module
Al 31 (2-ea)
G783
G783

Multiplexer
Channels 30-37
Channels 20-27

D30, D31
F30
F31

DP12-A 3

G718
M706
M707
W076

· Jumper (110 baud)
Receiver
Transmitter
Cable

NI I
M-N09
M-NIO
N03

· DPI 2-B 3

M405
M706
M707
.M216
W076

Crystal
Receiver
Transmitter
Flip-Flops
Cable

NI I
M-N09
M-NlO
Nl2
N03

DR12I

M216
G783
G783

Flip-Flops
Analog Cable
Relay Cable

L04
F33
F32

KE12

Ml 11
Ml 13 (3-ea)
Ml 15 (2-ea)
Ml 17
Ml21
Ml60 (3-ea)
M216
M906

Flip-Flops
(Remove)

L33
L35, L36, M33
L34,L29
M34, L30
L31
L37, M35, M36
M37
K27

KP12

M703

Schmitt Trigger

F03

KT12

Ml 17
M216

Flip-Flops

H27
H29

AM12

DM12 4

KF12-B 4

KW12-A

Notes:

Ml03
Ml 13 (2-ea)
Ml 15
Ml 17
M216 (2-ea)
M217 (3-ea)
M304 (2-ea)
M405
M719 (3-ea)

Selector

Flip-Flops
Amplifier
Crystal
Channel Select

D25
D24, D29
D23
D22
E09,Fl9
E03,E04,E07
D27, D28
Fl8
F20, F2 l, F22

1. Panel ADI2 is shipped with both the ADI2 and the DRI2.

DPI2-A - When the DPI2-A is used to drive a Teletype at llO baud, the M405 (location NI 1) and
M2I6 (location NI2) are not used. The G7I8 Module is placed in location Nll, thereby connecting
the PDP-I2 Teletype to the DPI2 input and output module.
DPI2-B - When the DPI2-B is used at other baud rates (0-+ 10,000), the crystal clock (M405, Nll)
is selected to be I28 times the baud rate.
For baud rates between 10,000 - I00,000, the wire from N12L2 to N12Ml is removed, and a wire
from NI2L2 to NI 102 is added. The crystal clock rate is then selected to be 16 times the baud rate.
Use cable BCOIA-25 for interconnection to Dataphone.
4. Installation of modules and cables is descn"bed in the procedure.
3.

(continued on next page)

Table 4-3 (Cont)
Option Module and Cable List
Option

Location

Note

Module
M503
M617
M623
G783
W023

Level Converter
Cable
Jumper Board (Delete)

F24
Dl7
D26
F25
E07

KW12-B

M401
M103
M870

RC Clock
Selector
Control

Fl8
D25
F25

KW12-C

M405
Ml03
M870

Crystal
Selector

Fl8
D25
F25

MC12

G020 (6-ea)

Delete

W023
G021 (6-ea)

Delete

G228 (3-ea)
G624 (3-ea)
Ml 13
Ml21
M169
M216 (3-ea)
M360
M617 (5-ea)
M720

Axis Select
Resistors

A07, A08, A09, B07, BOB,
B09
M26
A07, A08, A09, B07, B08,
B09
Al3, Bl3, B14
Al4, AIS, BIS
M27
M28
M32
M29, M30, M3 l
EIS
M22, M23, M24, M25, M26,
411
C-Dl 1, C-Dl3
A-Bl 1
A-Bl2

KW12-A
(cont)

W025
W025
TC12

Schmitt Trigger

Flip-Flops
Delay
Non-Exist Memory
4K STACK
Sense Stack Cable
Inhibit Stack Cable

Mll 1 (2-ea)
M112 (3-ea)
Mll3 (7-ea)
Mll5(7-ea)
Ml 17 (8-ea)
Ml 19 (2-ea)
Ml 21 (5-ea)
M160
Ml61
Ml69
M212
M222 (6-ea)

Decoder

M216 (9-ea)

Flip-Flops

M304 (5-ea)

Schmitt Trigger

Flip-Flops
Registers

A35, C21
A33, C24, DI 6
A26,A36,B24,B26,B38,
D29,Cl6
A27, A32, B27, B34, C25,
C27,C29
A25, A37, B33, B35, B36,
C23,El6,El7
A31,C22
A34,B25,B32,C26,E19
B29
A29
Al6
A38
A-Bl 8, A-Bl 9, A-B20,
A-B2 l, A-B22, A-B23
A28, A30, B31, B37, Dl9,
D20, El 8, E20, E25
Cl7,Cl8,Cl9,C20,Dl8
(continued on next page)

4-5

Table 4-3 (Cont)
Option Module and Cable List
Location

Note

Option

Module

TC12
(cont)

M307 (2-ea)
M401
M602
M617 (4-ea)
M901
G853
G882 (5-ea)
W023
W032
W512 (3-ea)
W520
W603
Rl07

Connector Cable
Unit Selector
Readers/Writers
Cable (Con)
Cable
Level Converters
Comparator
Amplifier
Delay

C28,C30
E21
B30
A23, A24, B23, B28
A40
FlO
F04,F05,F07,F08,F09
EOS
E-F06
F13, Fl4, FIS
Fl 1
Fl6
Fl2

M216

Flip-Flops

C32, C33

MIOl
Mll3
MllS
M216 (2-ea)
M711 (5-ea)
A615 (6-ea)
G783
G783

Interface

Flip-Flops
Control
D/ A Converter
VR12 Cable
503 Cable

C38
D29
C29
D38, E38
C-D37
E-F36, E-F37
F38
F39

M704
W023

Control
Cable

M-NOS
N04

TC12-F

Delays
Schmitt Trigger

russ 5
TU56 5
VC12

VR12 4
VRI44
XY12
503 5
5 • This option has modules already installed. Remove the tape and install the cables as described in

Notes:

Paragraph 4.2.1.

4.2.1 Installation of Panels and Cables
Panels are installed for the KW 12-A, AG 12, AD 12, and DR 12 options. These panels are installed on the PDP-12
as shown in Figure 4-1.
Use the following procedure when mounting these panels:
Procedure

Step

Remove screws and nylon washers from blank panel and save them.

Remove blank panel carefully, so as not to scratch the face of the panel
or damage any components (silicon wafer switches, wires, or jacks). Install new panel.
(continued on next page)
4-6

DR12-A

DEC TAPE
STORAGE
RACK
#1809544
OR BLANK
PANEL

TU55/56

DEC TAPE
STORAGE
RACK
#1809544
OR BLANK
PANEL

TU55/56

KW12
PANEL OR
BLANK
PANEL

VR12,VRt4,
OR

AD12 PANEL

503

PDP-12 CONSOLE
TABLE

I
I

DR12
PANEL
724
PIS

AM12
AG12
PANEL OR
BLANK

12-02•0

Figure 4-1 PDP-12 Equipment Layout

Step

Procedure

Before tightening screws, align panel sides parallel to panel above and below it,
and equalize any space between upper and lower panels.

Tighten screws, making sure nylon washer is between screw head and panel.

Remove any plastic covering which may have adhered to the front of the panel.

Inspect all switches and jacks for damage.

Check all knobs and jacks for proper alignment, tightness, and operation. If a
knob adjustment is necessary, loosen Allen set screws and adjust accordingly,
then retighten Allen set screws. If jacks are loose, check for damage, then.
tighten nuts. Be careful not to scratch front of panel.

For the KWl 2-A panel, a red wire will be taped to the cable on the back of the
panel. Remove the tape and route wire to the ON/OFF switch. This wire is a
+ IOV tap from the switch to the panel. Locate +1 OV on the switch and install
wire. Install the white ground wire to the 6.3 Vac transformer in the 724 Power
Supply.

(continued on next page)

4-7

Step

Procedure

Uncoil cables and remove any excessive tape at this time. Route cables through
the trough to the CP and memory. Install cables in their respective slots.

With the plenum door fully open, secure cables together with tie wraps.

Shut door, retying cables if necessary to prevent interference.

If cables are not marked, mark them at this time with slot location.

4.2.2 Unit and Cable Installation for TUSS, VR12 or VR14
The TUSS (Figure 4-2), VRl 2 (Figure 4-3), and VR 14 have mounting racks with slides attached, as shown in
Figure 4-4. These slides must be mounted before attempting to install the unit. The following procedure describes the installation of the units.
Procedure

Step

Assume a single cabinet (Bay 0) PDP-12 System configuration (Figure 4-1 ).
Sections marked A, B, and C respectively in Figure 4-1 initially contain blank
filler panels.
2

Remove the blank panels by grasping both sides of the panel and pulling
straight out.

• Remove the blank snap brackets.

For mounting two TUSSs and a VR12 or VR14, mount clip-nuts and insert
screws in the 3rd, 6th, 11th, 14th, 19th, 22nd, 27th, 30th, 3Sth, 38th, 43rd,
and 46th holes on each side of the frame. Do not tighten screws at this time.

Orient the left bracket (shown in Figure 4-4) to align the four slots with the
top four screws.

Pushing inward and upward, tighten screws. Use the same procedure for the
other brackets.

Extend the right and left tracks on slide brackets all the way forward until
they stop.

Align tracks on TUSS with cabinet brackets and slide unit in until it locks
(loud click will be heard).
CAUTION
The VR 12 weighs 70 lbs; therefore, two men are
required to lift and install it in the PDP-12.

To install VR12 or VR14, follow Steps 7 and 8 above.

Slide all units inward and check for clearance. Readjust one side at a time
until units properly clear one another.

Check all knobs and switches ~s described in Steps 6 and 7. Remove tape
from modules and check them for complete insertion in their respective
locations.

Connect TUSSs together with accord in back of TUSS (3-ft cord). Connect
bottom TUSS to power supply (6 ft). Route last cable neatly and use tie
wrap when necessary.
(continued on Page 4-10)

4-8

Figure 4-2 TUSS LINCtape Transport

Figure 4-3 VRI 2

4-9

BRACKET_J]

BRACKET
(SEE NOTE)

v~-=_;~;::_:_:_:_:_:_::_:_:_:_:;:O::_i~-~-~---~-:0-~-~N-~-D-O_W_N------------,'":Tt
TRACK

r==========~ CATCH

CID

~11

NOT£;
This bracket connects both
frock 011emblles.

FRONT

SIDE
12-02~3

Figure 4-4 TUSS, VR12, orVR14 Mounting Assembly

Step

Procedure

Connect 3-ft de cable to the top of the TUSS with green wire to+ lOV, black
wire to GND, and blue wire to - I SV connectors. Route cable to bottom
TU55 and connect as described above. Connect 6-ft de cable to power
supply and route neatly (using tie wraps) to bottom TUSS.

Ensure the Tl. ~55 transports can still be fully extended until they lock in the
maintenance position, without strain or interference with de or ac cables.

Logic connection for the TUSSs is as shown in Table 4-4. Cables such as
those in A6 and A3 through 83 are 3 ft in length. Cables in the AS and A2
through 82 are 6 ft in length. Be sure the cables do not interfere with opening of the TU55 and the rear plenum door.

Adjustments to the TUSS can be found in Paragraph 3.6.

The VR 12 or VR 14 ac power cord ( 4 ft) should be routed to the power supply
in such a manner that it does not interfere with the opening of the unit. The
cable in slot F38 is connected to the back of the display . All switches on the
back of the display should be set in the downward position . The M7 l l Display
Module switches should be set as described in Paragraph 3 . 8 .
Table 4-4
Interconnections of TU55

Top TU55 Location
A6
A-B3

Bottom TU55 Location

Mem Logic Location

F05

A-B3
A-B2

E~F06

4-10

4.2.3 TU56 Unit and Cable Installation
The TU56 transports are mounted similarly to the TU55, except that special brackets are used. These special
brackets, however, do not allow the TU56 (Figure 4-5) to be extended on tracks as the TU55.
CAUTION
TU56 weighs approximately 70 lbs; therefore, two men are
required to lift and install it.

Figure 4-5 TU56 LINCtape Transport

Procedure

Step

Performs Steps 1 through 4 of Paragraph 4.2.2.
2

Insert clip-nuts in both the front and rear frames in the 18th and 36th holes
(from the top). See Figure 4-6.

Install rear plate support block as shown in Figure 4-7.

Install rest plate front support as shown in Figure 4-6.

Align holes at rear of rest plate with those at rear of rest plate support block, as
shown in Figure 4-8. Insert screws.

Tighten rear and front plate support block screws.

Slide the TU56 (Figure 4-5) onto rest plate and push unit in.

Turn lock nuts on sides of door until door can swing open (downward).
(continued on Page 4-13)

4-11

12-0258

Figure 4-6 Front Assembly of TU56

FRONT FRAME

REAR FRAME
-

FRAME
SECTION

REAR PLATE
SUPPORT BLOCK

NOTE:
Locate support block in 36th hole from the top.
12-0257

Figure 4-7 Rear Plate Assembly of TU56

4-12

FRONT

FRONT
FRAME

REST PLATE
SUPPORT
BLOCK
REAR
NOTE:
Screwa A and B ore located in the 36th hole from the top.

12-02!54

Figure 4-8 Top View of TU56 Rest Plate Assembly

Step

Procedure

Align (with help because of its weight) the bottom TIJ56 with the clip-nuts and
insert screws.

Tighten screws, using a long Phillips screwdriver.

Adjust front door to open without hitting the equipment panel below it.

If door does not shut firmly, readjust lock slots on top of the TIJ 5 6.

Connect de cord to back of TIJ56 as in Table 4-5. Connect de cord to power
supply.
CAUTION
With the TU56, the green wire is +SV, not +lOV as
for the TUSS. Be certain when connecting end of
cable in power supply, that green is connected to
+SV.

Connect accords similarly as with the TU55, but route and tie these cables
to the cabinet frame (the TU56 does not move). Connections are discussed
in Step I 2, Paragraph 4.2.2.

Route logic cable connections and place as shown in Table 4-6.

Partial adjustments of the TU56 are provided in Paragraph 3.7 of this manual.

4-13

Table4-S
DC Voltage Connections
Voltage

Wire Color

-lSV
GND
+SV

Blue
Black
Green

Table 4-6
TU 56 Logic Cable Connections
Top TUS6 Location

Bottom TUS6 Location

A06
AOS
A-B09
A-BIO

Mem Logic Location

A06
EOS*
A-B09
E-F06

*This cable is not a I-to-I cable. When inserting, place end marked TU56 in TU56 slot.

4.2.4 K.F12-B and.DM12 Installation
For field installation of the KFl 2-B and the DMl 2, the following material should be received and checked out:

A processor unit with a hold-down bracket between logic rows N and P.

Sixty KF 12-B and DM 12 Modules listed in Table 4-7.

Software:

DEC-12-DOSA-PB, KFl 2-B Automatic Priority Interrupt Diagnostic Paper Tape

DEC-12-DOSA-D, KF 12-B Automatic Priority Interrupt Diagnostic Document

KF 12-B engineering drawings.

DM 12 engineering drawings.
NOTE
The DM12, which is part of the KF12, can be ordered as part
of the KF12 or as a separate option to the KF12.

Technical manuals:
PDP-12 System Reference Manual, DEC-12-SRZB-D (revised)
PDP-12 Maintenance Manual Volume II, Installation and Maintenance,
DEC-12-HR2B-D (revised)
PDP-12 Maintenance Manual Volume IV, Module Schematics

KFl 2-B modification hardware. These items are shipped only for field installation of the KF 12-B.

Cable duct brace.

Cable mounting bar with plastic cable clamps.
(continued on next page)

4-14

DMIS Solitron Diode, serial number 7016 or above, and Wakefield Compound.

An Airpax +SV, 2SA circuit breaker.

NOTE
If the PDP-12 System on which the KF12-B is being installed

has a BA12 Peripheral Expander Option, BA12 ECO Number S
must be installed on the BA 12. This ECO disconnects the BA 12
power source from a tap on the 724 Power Supply and installs
an H721 Power Supply in the BA12. If ECO BA12 Number S
is not installed, the +SY supply will be overloaded when power
is applied to the BA 12 and the +SY circuit breaker will operate.
Table 4-7
KF12-B and DM12 Modules
Module

Quantity

M002
Ml03
Ml07
Ml 12
Ml21
Ml27
Ml33
Ml3S
Ml39
MISS
MIS9
M90S
MIOI
Ml92
M20S
M207
M216
M238
M401
M61 l
M623
M627
M734
M906
M623*
M906*

I
I
I
I

Location
RIS
ROB
Pl2-Rl2
R29
P09,P36
POS
P03,P07,P30,P32,P33,P38,P40,R30
P06,R40
P29
R3S
P3S
P02, Rl6
Rl4
P39
R33, R37, R38, R39
R34
P31
R03,R04,ROS,R06,R36
P28
P04,P08,P34,P37,P07,R32
PIO, Pl 1, R09, RIO, RI 1, Rl9, R20
R02, R31
Pl3 - R13
R22, R23
R23, N24, R26, R27
R25, R28

2
I
8
2
I
I
I
2
I
I
4
I
I

I
6
7
2
I
2
4
2

*DM 12 Modules.

4-15

Use the following procedure to remove the central processor:
Procedure

Step

Unplug all option cabinets, except the RF08 cabinet. All power to the system
should be off except for the RF08 motor.
2

After noting that all cables are properly marked, disconnect nine interprocessor
cables from slots HOI, H02, JOI, J02, KOi, K02, LOI, L02, and M02. Leave
the memory end of each cable connected and allow the cables to hang.

Disconnect the Teletype cable from slot N02.

After noting that all cables are properly marked, disconnect nine console
cables from slots N28 through N36.

Disconnect the G 7 80 cable from slot MO I -NO 1. An ECO is installed on this
cable later in the installation procedure.

After noting that all cables are properly marked, disconnect all other cables
from the PDP-12 Central Processor.

On top of the processor main frame, on the module side, are red and white
wires that go to the logic rack fans. One at a time, remove the screw which
holds each plastic clamp for the fan wires. Remove the plastic clamp and
replace the screw immediately. These screws fasten each row of logic rack
connectors to the main frame of the processor. Exercise care not to jar the
PDP-12 door while performing this step.

Remove the five screws on the grill of the logic rack fan, remove the grill,
and put it aside.

Remove the three large screws that hold the processor to the hinge side of
the PDP-12 door.

With another person supporting the weight of the processor, remove the three
large screws (between the logic rack fans) that hold the processor to the open
side (opposite the hinge side) of the PDP-12 door.

Remove the processor from the door and place the processor in a safe place.
CAUTION
Do not place the processor on a hard surface with
the pins down unless heavy cardboard is placed between the hard surface and the pins.

Use the following procedure to install a new +SV circuit breaker in the 724 Power Supply. The +SV circuit
breaker is located on the back of the 724 Power Supply and is the uppermost breaker (of the two breakers) on
the power supply.
Step

Procedure
Remove the six screws that fasten the protective grill to the 724 Power Supply,
remove the grill, and put it aside.

2
3

Remove the two screws from the switch side of the +SV circuit breaker that
fasten it to the chassis of the power supply.
Inside of the power supply, a G824 Regulator Module is connected to the
+SV circuit breaker. Note the connector configurations of the two

Mate-N-Lock connectors on the component side of the G824 Module and disconnect the two connectors.
(continued on next page)
4-16

Step

Procedure

Remove the G824 Module and the +SV circuit breaker from the power supply.

Remove the two nuts that fasten the +SV, 20A circuit breaker to the G824
Module.

Note the positioning of the circuit breaker and remove it from the G824
Module.

Place the new Airpax +SV, 2SA circuit breaker (supplied with the KF 12-B
modification kit) on the G824 Module and fasten it firmly in place with the
two nuts from the old circuit breaker. Ensure that the terminals of the circuit
breaker make contact with the etch around the holes in the module board.

Replace the G824 Module and the new +SV circuit breaker in the power supply.

Replace and tighten the two screws on the switch side of the circuit breaker.

Connect the two Mate-N-Lock connectors to the component side of the G824
Module in the same configuration as they were before removal. Ensure that
the G824 Module is not shorted against the wiring from the ac outlets of the
724 Power Supply.

The KF 12-B option requires that the DM 1S Diode in the 724 Power Supply be a Solitron dio_de with serial number
7016 or above. If the diode does not meet this requirement, it must be replaced with the DM 1S Solitron Diode
supplied with the KF 12-B modification kit. The DM 1S Diode is a diamond shaped component located on the
central portion of the vertically mounted side chassis of the 724 Power Supply. Use the following procedure to
install a new DM 15 Diode in the 724 Power Supply:

Step

Procedure
Without disconnecting the leads to the diode, remove the two screws that
fasten the diode to the chassis of the 724 Power Supply.

Spread the Wakefield silicon paste compound (supplied with the KF 12-B
modification kit) smoothly across the back of the new DM 15 Diode.

Position the new diode on the 724 Power Supply chassis in the place that
had been occupied by the old diode with the green dot on the diode at the
top and the screw holes lined up.

Replace the two screws that fasten the diode to the power supply chassis and
tighten them firmly.

Hold the old diode in a position with the green dot at the top and disconnect
each lead separately, and connect them to the corresponding terminals on
the new diode. Ensure that none of the leads of the four terminals are shorting against each other.

Replace the protective grill on the 724 Power Supply and fasten the six
screws that hold the grill to the power supply frame.

Installation of the KF 12-B option requires that one of the braces for the cable duct be replaced. The old cable
duct brace protrudes approximately 1 in. and interferes with the modules in logic rows P and R. The brace that
must be replaced is located above the 724 Power Supply at the corner nearest the hinge side of the PDP-12 cabinet door. The brace is attached to the PDP-12 frame and supports the plastic cable duct. Use the following procedure to install the new cable duct brace:

4-17

Procedure

Step

Remove the two screws that fasten the cable duct brace to the PDP-12 frame.

Remove the top cover of the cable duct and separate the cables to locate the
bolt in the bottom center of the cable duct where the brace is attached.

Unfasten the brace from the cable duct by holding the brace and removing
the bolt; then remove the brace.

Line up the hole in the new brace (supplied with the KP 12-B modification
kit) with the hole in the bottom of the cable duct and replace the bolt to
fasten the new brace to the cable duct. Tighten the bolt firmly.

Realign the cables in the cable duct and replace the top cover of the cable
duct.

Replace the two screws that fasten the brace to the PDP-12 frame and tighten
them firmly. The new brace should not protrude from the bottom edge of
the cable duct.

An additional cable mounting bar is required to support the cables from the processor to the adjacent cabinet. Use
the following procedure to install the cable mounting bar (with plastic cable clamps):
Step

Procedure
Position the cable mounting bar against the front and back portions of the
cabinet frame on the hinge side of the cabinet, above the cable duct. Refer
to the engineering drawing of the mechanical assembly for the correct position.

Fasten the cable mounting bar to the cabinet frame with the screws provided.

Installation of the KP 12-B option requires that a minor ECO be made to the G780 Power Connector that was
removed from slots MOl-NOl. Use the following procedure to perform this ECO on the G780 Power Connector.
Step·

Procedure
Hold the G780 Connector Module with the component side up and the handle
at the bottom. Note the metal tab that protrudes from the right side of the
module to prevent the connector module from shifting position when it is
plugged into its slot.

Remove this metal tab which is riveted to the connector board.
CAUTION
Be careful to avoid getting metal fragments inside the
equipment cabinet or in the logic rack.

Use the following procedure to install the new processor unit in the PDP-12 cabinet:
Step

Procedure
One-by-one, remove each module from the old processor unit and plug it into
the new processor unit in the same slot designation from which it came.

Use the module utilization drawing from the KFI 2 engineering drawings and
Table 4-7 to determine the correct location for each of the sixty new KP 12-B
and DM 12 Modules supplied with the KP 12-B modification kit. Install each
module securely in its correct location in the new processor unit.
(continued on next page)

4-18

Step

Procedure

With the help of another person, mount the new processor unit on the PDP-12
cabinet door and fasten securely with the six large screws.

Replace the grill on the logic rack fan and fasten securely with the five screws.

Replace the plastic clamps for the red and white fan wires that run along the
top of the main frame of the processor. One at a time, remove each screw,
replace the plastic clamp, replace the screw, and tighten it firmly. These screws
fasten each row of logic rack connectors to the main frame of the processor;
exercise care not to jar the PDP-12 door while performing this step.

Replace each of the nine interprocessor cable connectors in slots HOI, H02, JOI,
102, KO 1, K02, LO I, L02, and M02. Ensure that each connector is correctly

placed in its designated slot.
7

Replace the Teletype cable connector in slot N02.

Replace the nine console cable connectors in slots N28 through N36. Ensure
that each connector is correctly placed in its designated slot.

Replace the G780 Cable Connector in slot MOl-NOI.

Installation of the KF 12-B requires that all external options be recabled. A PDP-12, with a KF I 2-B, can have
only one data break option unless a DM I 2 is installed on the KF 12-B; the system is then capable of handling three
data break options. Data break devices use five cables:

Buffered AC cable

Buffered MB cable

Extended data cable

Extended data address cable

I/O cable (EXT AC, SKP, etc.)

Non-data break devices use only three cables:

Buffered AC cable

Buffered MB cable

I/O cable (EXT AC, SKP, etc.)

When a DM04 Direct Memory Access Multiplexer is used in the system, in addition to the DM 12, the DM04
options have the highest priority and the DM 12 options follow. An extra cable is supplied with the DM04 to connect the DM04 fo the KFI 2-B. The three highest priority data break options are connected to the DM04; up to
three more data break options can be connected to the DM I 2. If a DM04 is not included in the system, the data
break devices (up to three) are connected to the DM 12 in order of priority as shown in Figure 4-9.

NOTE
The DM04 must have ECO DM04-000IS installed in order to
operate with the KF12-B.
In recabling the external options, use the shortest cables for the shortest distances and save the longer cables for
the extended data and extended data address cables. When each KFI2-B modification kit is shipped, the particular
system configuration is considered and extra cables are included where required.

4-19

COAXIAL CABLES TOTAL LENGTH ON BUS 45ft. MAX.

EMf2

BAC
EPf2

DEVICE 0

BMB

DEVICE

I/O BUS*
KF 12
DM12
P20
P2f

HIGHEST
PRIORITY

DATA ADDRESS
DATA BITS

DEVICE 2

LOWEST
PRIORITY

DATA ADDRESS
P22
DATA BITS
P23
DATA ADDRESS
P24

DATA BITS

P25
COAX I AL CABLES -MAX. LENGTH 25 ft.
*If the priority interrupt system is used in the KFf2B this coble is connected separately from each device.
(ref. BS-KFl2-CAB ),
12-0299

Figure 4-9 DM 12 Cabling Diagram

Cables that go from the processor to options in the adjacent cabinet must be routed through the plastic cable
clamps on the newly installed cable mounting bar. Be careful to route these cables neatly and to allow enough
extra cable for a service loop between the processor and the cable mounting bar, so that the cabinet door may be
opened and closed without interfering with the cables.
Use the following procedure to recable the external options:
Procedure

Step

Remove all the cables for buffered AC, buffered MB, and 1/0 for the options.
If data break devices are used, remove the cables for extended data and
extended data address. -

Connect the first section of the buffered AC cable from slot N 14 of the processor to the buffered AC slot of the closest option. Run the next section of
buffered AC cable from that option to the buffered AC slot of the next closest
option. Continue this process until the buffered AC cable goes through all
break and non-break options.

Connect the first section of the buffered MB cable from slot N 15 of the
processor to the buffered MB slot of the closest option. Run the next
section of the buffered MB cable from that option to the buffered MB
slot of the next closest option. Continue this process until the buffered MB
cable goes through all break and non-break options.

When the DM04 is included in the system, connect the extended data and
extended data address cables for the three highest priority options into the
DM04 in accordance with instructions provided with the option. Also, connect the cable supplied with the DM04 from slot B 17 of the DM04 to slot
P26 in EPl 2.

(continued on next page)

4-20

Step

Procedure

Connect the extended data and extended data address cables as listed below
and shown in Figure 4-9.
EP12 Slots
Ext Data Addre~

Ext Data

P20
P22
P24

P21
P23
P25

Device 0
Device 1
Device 2
6

Install the 1/0 cables for external interrupt request (EXT AC, SKP, etc.) for all
break and non-break devices. Run a separate cable from each device to EP 12
slots P 14 (for highest interrupt priority), Pl 5, Pl 6, Pl 7, Pl 8, and P 19 (for
lowest interrupt priority). Refer to engineering drawing BS-KF 12-CAB for
further information on the 1/0 cabling.
NOTE
When extra cables are left after completing system
cabling, they should be returned to the local DEC
Field Service Office.

Install the hold-down bracket on the processor frame and fasten the bracket
to the frame with the captive screws.
CAUTION
Ensure that the -30V voltage tab on the G780
Power Connector Module has an insulating sleeve
installed on it so that the voltage tab does not short
against the hold-down bracket.

Recheck the installation of all cables and modules. Ensure that all cable
connectors are installed in the correct slots and that all modules are installed
in accordance with Table 4-7 and the module utilization charts in the engineering drawings. Be certain that the cabinet door closes freely without
crimping cables against the power supply and the VR14.

The priority level assigned to each interrupt level is determined by a jumper module, M905 at location RI 6.
Drawing D-BS-KFI 2-0-PAl shows the priority lines of the KF 12-B system peripherals connected into this M905
module and the jumper configuration of the module as it is shipped. It is possible to change the jumper configuration on the module in order to alter the priority levels on the interrupt bus (internal and external).
As an example, if a user does not have the power fail option and wishes to assign the peripheral connected to
EXT LEV 9 to a priority level which is higher than the internal options, the following jumper wires could be
changed on the M905 module.
a.

Disconnect the jumper from 12 to H2

Disconnect the jumper from Al to B 1.

Connect a jumper from H2 to B 1.

4.3 CHECKOUT
There are 23 prewired options for the PDP-12. The options (listed in Table 4-1) are checked out using the Adjustment Procedures in Chapter 3 and the write-ups supplied. Only the DP12-B, TC12-F, TUSS, TU56, VR12, and
KFl 2 options will be discussed here.

4-21

4.3.1 Checkout of the DP12-B
Before commencing checkout of the DPl 2-B, determine the baud rate by using the following formulas.
For baud rates of 110 to 10,000:
B=F/128
where

B =baud rate
F =frequency of M405 crystal

For baud rates of 10,000 to 100,000:
B = F/16
where

B =baud rate
F =frequency ofM405 crystal

If the baud rate is in the 10,000 to 100,000 range, the wire from N12L2 to Nl2Ml is removed. A jumper is then

installed from Nl2L2 to NI 102. Run PT08 Dataphone Test (DEC-08-D8PA-PB) for the.ranges of 100 ~ 100,000.
For further infonnation, see the PT08 test write-up (DEC-08-D8PA-PB).
4.3.2 Checkout of TC12-F
Procedure

Step

Load the TC 12-F diagnostic (MAINDEC- l 2-D3EA-P3) and, following the
instructions contained in the write-up, allow the test to run for ten minutes
minimum.

Load the TC 12-F conversion program PRTC 12-F ( 12-YIYB-PB) and, after '
following the procedure in the write-up, convert a copy of the LAP6-DIAL
tape included in this kit to PDP-10 format and then back to PDP-12 format
(see Table 4-8).

Restart the LAP6-DIAL editor contained on the last converted PDP-12
format tape and type~ CL ) . When the work area is clear, type
~AP) PRTC12-F, 0) .

Mount a scratch tape (LAP6-DIAL format) on UNIT 1.

When the program has been added to the working area, type ~ AS )
When the program has assembled without an error, type~ LO ) .
Then depress 1/0 PRESET - LINC MODE - START 20. The first frame
of the PRTC 12-F program should be displayed. This completes the checkout and acceptance of the TC 12-F option.
Table 4-8
Format Conversion Table

Read from Format

Block Number

Number of Blocks

Write to Format

Block Number

PDP-12
PDP-10

0
0

10008
5268

PDP-10
PDP-12

0
0

4-22

4.3.3 Checkout of the LINCtape System
PDP-12 LINCtape Systems are comprised of the TCl 2 LINCtape Automatic Control; and,

TUSS transports or,

TU56 transports or,

TUSS and TU56 transports together;

with or without a VRl 2 Point Plot Display System.
Therefore, the LINCtape System configuration is important to note when using the following procedure:
NOTE
If the system has only one TU55, with or without a VR12
Display, use only the MARK12 section to test the tape unit.
' If the LINCtape system has any other combination of tape
transports and video display, all of the following procedures
are used.

Step

Procedure
If the system has two TUSSs or two TU56s, skip to Step 3.

If the system has a TUSS and TU56, check out both sections of the TU56
first, then do the TUSS with one TU56 section selected.

Tum UNIT SELECT switches until UNIT 0 is the bottom (or right tape transport) and UNIT I is the top (or left tape transport).

Place LAP6-DIAL MAINTENANCE tape (DEC- l 2-D7 AC-UO) on UNIT 0
and install a scratch tape on UNIT I as described in Paragraph 2.2.2.

Start LAP6-DIAL as directed in Paragraph 2.2.2.

Type -+- LO MARK 12, 0 ) .

Ensure that WRITE ENABLED on both selected transports is selected, and
that both units are in REMOTE.

If a video display is in the system, the MARK 12 program will be displayed on
the screen; skip to Step 10. If not, continue through Step 9.
a.

Displayed is the following:
1 - STD LINCTAPE FORMAT
2-128 WORD FORMAT

Press Teletype key 1 for standard LINCtape format.

Press Teletype key LINE FEED to exit to MARKI 2 program.

Tape on UNIT 1 will vibrate. Press the MARK key on the
PDP-12 Console.

When program is finished (tapes will stop) the following will be
displayed (approximate running time - 3 min).

(continued on next page)

4-23

Procedure

Step
8 (Cont)

TGOOD COPY
1 - MARK ANOTHER TAPE
2 - EXIT TO DIAL

Press Teletype key 2 and LINE FEED.

When tape stops, type~ LO PIP, 0 ) .

Advance tape on UNIT l to the left about 3 ft.

When UNIT 0 stops, the following will be displayed.
PIP
A - AUXILIARY MODE
B - BINARY MODE
S - SOURCE MODE

Type A$ ) .

PIP will then display the following:
PIP
C - COPY SPECIFIED BLOCKS
D - DUPLICATE UNIT 0 ON UNIT 1
S - COPY SYSTEM

Type D ) .

UNIT 0 will rewind. Then UNIT 1 will rewind to b~ock 000 and begin
copying UNIT 0 on UNIT 1. The approximate copy time is 5 min. If
the tape stops before the 5 min is up, without initiating a return and
LINE FEED to the Teletype, an error has occurred. Displayed will be
the following:
TYPE OF ERROR
ERROR: BLOCK NUMBER

xxx
A - ACCEPT AS IS
R-TRY AGAIN
'\

S- SKIP PAST FAULTY BLOCK

Try to recopy the block by typing R ) . If the failure persists, try to
skip past faulty block and investigate tape.
16

Reverse the UNIT SELECT numbers and repeat Steps 9 through 15.

When more than two LINCtape transports are available in the system,
repeat the applicable steps for all combinations of units.

4-24

4.3.4 Checkout ofVR12 or VR14
The YR 12 is illustrated in Figure 4-3. Table 4-9 contains a description of the front knobs and adjustments. Refer
also to Paragraph 3.8 for VRI2 adjustments. Refer to the VRJ4 CRT Display User's Manual (DEC-12-HRZA-D)
for checkout of the VR 14.
Table 4-9
VR12 Controls
Control

Function

CHANNEL
BRIGHTNESS
XGAIN
XPOS
YGAIN
YPOS

Selects one or both channels for scope display
Controls level of brightness
Controls horizontal size of display
Controls horizontal position of display
Controls vertical size of display
Controls vertical position of display

To checkout the VR12, use DISPTST on the LAP6-DIAL maintenance tape (DEC-12-D7AC-UO). Also use PIP
and MARKI 2 displays. Check the displays for the following:

Evenness of lines

Continuity of lines and characters

Clarity of lines and characters

Focus

Brightness

Flicker

M71 l switch settings

4.3.S Checkout of the KF12-B and DM12
Step

Procedure
Check the +5V line for a short circuit to ground by measuring from pin MI A2
to ground with an ohmmeter on the 1-5 ohm scale.

Turn on the PDP-12 System.

Measure the voltage output of the +5V power supply at pin MI A2. It should
be from 4.75V to 5.25V. If the output is not within these limits, check the
output with and without load.

Run the following diagnostic programs in the order listed (refer to Appendix D):

CBL

ADRSHI

INST 2B

JUMPSLF

CPTST 2

CPTST 3

TC12 I

TCl 2 II

DISPTST

(continued on next page)

4-25

Step
4 (cont)

Procedure
j.

PIP - copy Tape 0 onto Tape 1

EXT CB (if applicable to the system)

EXT MCI 2 (if applicable to the system)

KW 12 (if applicable to the system)

Run any other diagnostic programs that pertain to the particular system.

With an oscilloscope connected to pin P28D2, adjust the potentiometer on M401
in slot P28 for display of a pulse every 200 ns (5 MHz frequency).

Run the KF 12 diagnostic program. for 15 minutes.

Run the PDP-12 System Exerciser, MAINDEC-12-D78A-UD for 45 minutes.
,(This exerciser checks out the complete DM 12.)

4-26

CHAPTER 5
TELETYPE MAINTENANCE
MODELS ASR 33 AND 35

This chapter contains information pertinent i:o the maintenance of the Teletype Models 33 ASR and 35 ASR, and
associated control logic. f
S.1 EQUIPMENT
Table 5-1 lists the special tools needed for maintenance of the Teletype. All of these items can be obtained from
Digital Equipment Corporation or from the Teletype Corporation.
Table 5-1
Teletype Maintenance Tools
Item

Part No.

8 oz. scale
32 oz. scale
64 oz. scale
Set of gauges
Offset screwdriver
Offset screwdriver
Hand wheel
Handwheel adaptor
Contact adjustment tool
Gauge
Gauge
Gauge
Bending Tool
Extractor
Tweezer
Spring hook (push)
Spring hook (pull)
Screw holder

110443
110444
82711
117781
94644
94645
161430
181465
172060
180587
180588
183103
180993
182697
151392
142555
142554
151384

Table 5-2 lists the maintenance programs supplied by DEC to aid in maintaining the Teletype Models 33 ASR and
35 ASR and associated control logic.

5-1

Table 5-2
Maintenance Programs
DEC Number

Use

Reader

MAINDEC-8I-D2PB

Function test and exercisor for the 33 and 35 ASR
Teletype paper-tape reader

Punch

MAINDEC-8I-D2QB

Function test and exercisor for the 33 and 35 ASR
Teletype paper-tape punch

Keyboard

MAINDEC-8I-D2RB

Function test and exercisor for the 33 and 35 ASR
Teletype keyboard

Combination

MAINDEC-8I-D2TB

Exercisor program used to test simultaneously the
33 and 35 ASR Teletype printer and punch

Program Test

5.2 PREVENTIVE MAINTENANCE
Preventive maintenance of the Teletype is scheduled on the same frequency as discussed in Chapter 2.
CAUTION
Do not use alcohol, mineral spirits, or other solvents to clean
plastic parts with protective decorative finishes. A soft cloth
should be used to remove dust, oil and grease on parts or subassemblies that are usually clean.
To clean plastic surfaces, use any one of several household cleaner-waxer liquids, such as "Jubilee" or "Jato". To
clean the printer platen, a lacquer thinner is recommended.
During an overhaul, subassemblies and metal parts can be cleaned in a bath of trichlorethylene. Proper lubrication
should be performed often.
5.2.1 Weekly Tasks
Step

Procedure
Inspect the platen and paper guide; wipe clean, using a soft dry cloth.

Clean external areas of the paper-tape punch and reader, using a soft
brush or cloth.

Remove and empty the paper-tape punch chad box.

Run Teletype combination test (MAINDEC-8I-D2TB) for approximately
15 minutes.

5 .2.2 Preventive Maintenance Tasks
Step

Procedure
Inspect the platen and paper guides. Clean the platen, using a lacquer thinner
to restore its surface.

Clean ribbon guides and replace the ribbon if necessary.

Remove the cover and check for vibration effects such as loose nuts, screws,
retaining clips, etc.
(continued on next page)

5-2

Step

Procedure

Remove distributor rotor and clean disk surface, using cotton swabs moistened
in freon or trichlorethylene.

Check selector magnet coil for signs of overheating.

Clean between the selector magnet pole piece and armature with bond paper
to remove any lubricant or dirt.

Clean and lubricate the Teletype as outlined in Teletype Bulletin 273B. Follow
instructions literally to prevent over-lubrication.

The following adjustments should be checked; the pages cited are from Bulletin
273B, Volume 2.
Part

Part Number

Page Number

Trip Shaft
Trip Lever
Brush Holder (Distributor)
Clutches
Code Bar Reset
Print Suppression
Blocking Levers
Print Suppression
Carriage Drive Bail
Print Trip Lever
Dash pot
Final Printing Alignment
Line Feed
Keyboard Trip Lever
Reader Trip Lever
Detent Lever
Sensing Pin
Tape Lid Latch Handle
Feed Pawl
Registration

574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-122-700
574-124-700
574-124-700
574-124-700
574-124-700
574-125-700
574-125-700

13
14
15
16-·24
30-34
35
37
43
44
61-62
78
85
89-95
141
6-9
IO

15
18
11
12

Run each of the Teletype MAINDEC Programs for at least two passes each.

Check that the tape holes are being punched cleanly.

5.3 CORRECTIVEMAINTENANCE
Figure 5-1 is a simplified schematic drawing of the control circuits for the Teletype. Details of the cable connector
are included to show how a Teletype is mcxlified to operate with the PDP-12. During off-line operation, the keyboard distributor effectively drives the printer selector magnet. As a result, any character received from the keyboard or paper-tape reader is automatically reproduced on the printer and paper-tape punch. During on-line
operation, this continuity is broken and a Teletype receiver (M706) is used to accept the input from the reader
or keyboard while a Teletype transmitter (M707) is used to drive the printer and paper-tape punch. The clock
(M452) develops a TII clock (880 Hz) and a TTO clock (220 Hz).

5-3

AC BITS

AC INPUT

TTY TRANSMITTER
M707

TTY RECEIVER
i-_ TTI CLOCK
M706
r-NM2
M~}

•

TTY OUTPUT

CLOCK
M452

TTO CLOCK

TTY INPUT
RDR RUN

rTEL.ET°vPE: coNNEcToR - - - - - - - - - - .,

rASR33-- -

I W076(0)

I TTY
~C7: ~C4

I
-f
I
I

_j_

*C6

=j=C3 ...

,,-

~) 05

fcAeLE-~"]_

....6

.,K
v

ct
l_c2

I
I

RELAYR2

R41

RELAY_!
N 4

~p ..3

*C1
~08
~

-'I.

R8 R7

I
I
I

C:·

R5
..M

KEYBOARD

SEl..ECTOR
"""NET
DRIVER

...

..M1..07
,

~~03.YL
rf02

I
I

, I
, I

-'I.
7

'1>1

-3ovl

L--------- - - - - - - - .J

Figure 5-1 Teletype Connections

--,

SELECTOR
MAGNET

I
I

2•

4•

5•

8•

I
_J
~- ---I- - + - - - TB

r4;;5

- --

--..,

I READER CONTROL I
I
r---

I
I

I
I
1

l~~

L____ J

..N..

TTYI NPUTI

I
L
______

I
I
I

- - -:- -

r--

I
I

~ 1.D6

IGNo·c

1-15V B

DIS~UTOR

1+5V A

:1~~~RL2

L1
s
L-~R~~~NO~ _j
I

12-0088

These clocks are used to shift the bits through the transmitter and receiver buffers. Adjustment is made by
viewing the TIO clock output with the oscilloscope probe on N08K2 and adjusting the trimpot for a 4.5-ms to
4.6-ms repetition rate. Most Teletype problems can be traced to one of the four areas listed:

33 and 35 ASR Keyboard or Reader

33 and 35 ASR Printer or Punch

M706 Reader

M707 Transmitter

Isolation of bit-related problems is fairly simple. Off-line duplication can usually determine whether the problem
is in the Teletype or the control logic. Steps may also be taken to isolate the problem to subassemblies within the
Teletype. Picking up bits during a Read operation can be caused if any of three sets of contacts, which are tied in
parallel, are defective. Reader, keyboard, and answer-back contacts provide parallel inputs to the distributor contact disk. Bit pick-up problems can be isolated to one of these three areas by disengaging the related contact from
the suspected contact set.
Printer/punch problems can sometimes be isolated by comparing the printed character with the output of the
paper-tape punch. If the printed character agrees with the punch output, and both are incorrect, then the problem
lies in the selector mechanism or in the Teletype Transmitter Module (M707). If the printed character and the
paper-tape punch output disagree, and the paper-tape punch output is correct, the problem lies within the printer
assembly.
Figure 5-2 illustrates the Teletype interface with the computer.

PDP-12

ACCUMULATOR

...... '

I
>
>
I,,/,,.-.-

- --~~;:-----+ 2.5V

START.

GND
1
uN tT

- - ---::,;; /
3

2__ -

1
uN\T luN 1T

uN\T

.,.,

'' ''

....
' - 1 _......_ ._ _ _
sT_o_P_ _ _

Iu~1T Iu~1T Iu~1T I

uN1.T

Iu~1T I

2
UNITS

- - - - - - - - - - - 11 UN ITS OF Tl ME - - - - - - - - _ . . , .
11-00IO

Figure 5-2 Teletype Signal Waveform and Bit Relationship for the Character "U"

5.4 TELETYPE PARTS
Users who do not have personnel trained in the maintenance and repair of Teletype units should keep a complete
spare Teletype unit near the computer. If the on-line unit becomes defective, substitute the spare to avoid computer down-time. However, many users have facilities for the maintenance of Teletype units, in which case it is
suggested that spare parts be stocked as listed in Table 5-3, and that one of each of the Teletype maintenance tools
listed in Table 5-1 be stocked. All of these items can be obtained from the Digital Equipment Corporation, or from
the Teletype Corporation.
5-5

Table 5-3
Spare Parts for Keyboard Model 33 ASR Teletype
Quantity

Item

Part Number

Circuit Board
Tape Feed Sprocket
Lever, universal
Fuse (3.2A)
Distributor Brush
Belt-Driven Gear
Drive Gear
Belt
St.aft
Bearing

181821
183071
182240
120167
180979
181420
181411
181409
181007
181002

2
2
2
2
1
1
2
1
2

5-6

APPENDIX A
MAINTENANCE AND SERVICE OPTIONS

Digital Equipment Corporation's Field Servic;., organization offers a wide range of services for DEC equipment
users. Customers may ch~ose from a broad selection of service contract options and Per-Call Service or Depot
Repair Maintenance plans to ensure optimum operating efficiency for their DEC equipment.
A. I SERVICE CONTRACTS

Setvice contracts are tailored to the user's individual operation. In addition to providing all the necessary parts,
labor, and test equipment required for remedial maintenance, service contracts also ensure system reliability by
providing scheduled, systematic preventive maintenance. Planning and budgeting are greatly simplified because
these contracts allow the user to fill his maintenance needs at a fixed, monthly charge.

A. I. I Service Contract Options
On-call service contract coverage provides remedial maintenance when the customer notifies DEC of a system
malfunction. Preventive maintenance is scheduled and performed during the period selected by the user. The
principal period of coverage consists of eight consecutive hours of on-call coverage during the period 7 a.m.
through 6 p.m., Monday through Friday. The user can extend his coverage from the principal period by selecting:
a.

12 consecutive hours of on-call coverage

16 consecutive hours of on-call coverage

20 consecutive hours of on-call coverage

24 consecutive hours of on-call coverage

Coverage of 24 consecutive hours, Monday through Friday, begins on Monday of each week at 7 a.m. and terminates on Saturday of each week at 7 a.m.
The Saturday and Sunday periods of coverage consist of eight consecutive hours of on-call coverage during the
period 7 a.m. through 6 p.m. As with the principal period of coverage, Saturday /Sunday coverage can be extended
to 12, 16, 20 and 24 hours.
An on-site resident engineer plan can be implemented if the size, complexity, and/or critical nature of an installation require such a plan. The services of a resident engineer consist of 40 hours of coverage during the normal
work week. In addition, all necessary spare parts, materials, and test equipment are physically stationed at the
user's site to further ensure prompt and efficient remedial and preventive maintenance services. Monthly rates
for contracted coverage are supplied on request.
There are no additional charges for travel in connection with service contracts except for remote installations.
Remote installations are defined as installations located at a distance greater than 100 miles from a DEC Field
Service Office.
A-1

A.1.2 Eligibility for Service Contract Coverage

A pre-service contract inspection is required for installations that were not under DEC's maintenance responsibility
immediately prior to the requested commencement date of the service agreement. All charges associated with this
inspection (including travel, labor, and parts) are billed to the user at the prevailing standard DEC rates. A minimum charge is associated with the pre-service contract inspection. No inspection is required for service agreements
that are scheduled to commence immediately after the expiration of a standard DEC warranty or service contract.
A.2 PER-CALL COVERAGE

Per-call coverage is designed to permit the users of DEC equipment to obtain service on a time and materials basis.
Requests for per-call coverage are considered after requests for service contract coverage; thus, only users with
their own service capabilities or users who are not critically tied to their equipment are encouraged to use this
fo~ of coverage. All charges for per-call coverage are computed on a portal-to-portal basis. Commercial travel
expenses related to the performance of services are billed as incurred. Material and parts consumption associated
with per-call coverage is charged to the user at the prevailing prices listed in the DEC Spare Parts Catalogue. Labor
charges for per-call service are on an hourly basis and are available on request.
A minimum charge for per-call service applies to each service call; in addition, DEC neither implies nor guarantees
the availability of per-call coverage outside the hours of 7 a.m. through 6 p:m., Monday through Friday. Users in
need of extended periods of coverage are encouraged to use the many service contract options available.
Users receive an invoice for all service rendered under per-call coverage. It is the responsibility of the user to inform the DEC Field Service Office servicing the equipment of any special billing instructions related to the use of
per-call coverage. Such notification must be rendered before the commencement of any services on the part of
DEC; in the absence of such notification, invoicing shall be accomplished in accordance with procedures determined by DEC. Installations requiring Purchase Orders for the authorization of work performed on a time and
materials basis are encouraged to submit a blanket order for one year's duration to cover such services. There will
be no additional charge for processing and administering such blanket orders. Terms for all services provided on a
per-call basis are net 30 days. In addition to the charges outlined above, customers are also charged for all federal,
state, municipal, or other government, excise, sales, use, occupational, or like taxes, now in force or enacted in the
future, incurred as a result of the performance of per-call service. Installations enjoying tax exemption are requested to present,their current exemption certificate number at the time that per-call service is rendered or with
the submission of the blanket Purchase Order.
A.3 DEPOT REPAIR

Depot repair facilities have been strategically located throughout the world to enable users of DEC equipment to
receive prompt, efficient service on many standard DEC optibns. Depots are also fully equipped to service and
completely rebuild, if necessary, ASR and KSR Teletypes. Further, users of DEC equipment interested in purchasing rebuilt ASR and KSR Teletypes, or using their existing Teletypes on a trade-in basis toward the purchase
of new machines, are urged to contact their nearest DEC Field Service Office for further information.
Depots are fully equipped and staffed with experienced personnel to offer rapid and economical repair services to
the DEC customer. At the user's option, a national transportation firm, contracted by DEC, can be used to route
equipment to and from the depot facility.
Charges for depot service, in addition to freight and insurance both ways, are computed per hour for labor, parts,
and material consumed. There is no minimum charge for the use of the depot repair facility.

A-2

Customers wishing to use the depot facilities are requested to contact the nearest depot and furnish the following:

Customer name

Customer address

Purchase Order number

Billing address

Name and telephone number of individual

Type, Model Number, and Serial Number of equipment to be serviced

Brief description of service problem or malfunction

Mode of transportation to be used (DEC carrier or other)

Upon receiving the above information, the depot issues a return authorization number that enables the user to ship
the equipment for servicing.
A.4 FIELD INSTALLATION OF ADDITIONAL DEC OPTIONS

Customers wishing to expand their existing systems by purchasing additional DEC options may elect to have the
installation of the new equipment performed at a fixed rate to facilitate the budgeting and purchasing processes.
Field installation rates are available on request. To compute the installation charges for an option or group of
options, the total charge is equal to the sum of the option installation charges plus a one-time travel charge.
For the purpose of performing field installations, remote locations are defined as areas outside those areas normally serviced by DEC or its subsidiaries. Requests for installations in remote locations are considered on an
individual basis. Field installations are performed from 7 a.m. to 6 p.m., Monday through Friday. A minimum
charge is associated with a field installation.

A-3

APPENDIX B
CUSTOMER ACCEPTANCE

Customer acceptance of the PDP-12 consists of a demonstration of machine operation by running all diagnostics
and an operating test of the system software. Some of the symbolic tapes provided with the software package
are not used; these tapes are usually subroutines used in conjunction with main programs, and are verified when
produced.
B.1 SPECIAL CUSTOMER REQUIREMENTS

Any special customer acceptance requirements must be submitted to DEC at least 30 days prior to final acceptance. All customer acceptance requirements must be approved by the DEC PDP-12 Product Line Manager and
Product Support Manager. Approved customer-specified acceptance requirements are listed on the construction
requisition with proper reference to detailed documents.
B.2 CUSTOMER PROGRAMS
Acceptance tests are not contingent upon any customer programs unless these programs and their write-ups are
supplied at least 30 days in advance of final acceptance, and are approved by the DEC PDP-12 Product Line
Manager; this statement includes those programs and documents the customer deems "classified material". The
programs must include ASCII and binary tapes, write-ups, and listings. These tapes are returned to the customer
with the machine. In the event of difficulties, the customer must agree to send a capable representative to DEC
in Maynard, Mass.
The DECUS library receives copies of all programs submitted, and the librarian obtains written customer approval
before publication.
B.3 SPECIAL CUSTOMER ACCEPTANCE TESTING
All special on-site acceptances must be listed on the construction requisition with reference to detailed documents
and will be exactly duplicated in-plant prior to shipment. Any special apparatus and test descriptions necessary
for acceptance must be supplied, with full documentation, to DEC thirty days prior to customer acceptance. This
documentation shall include: programs, listings, prints, block schematics, circuit schem.atics, manuals, and comprehensive operating and interfacing instructions. Any deviations must be waived by the DEC PDP-12 Product
Line Manager and the DEC Field Service Manager or their assigned representatives.
B.4 DIAGNOSTICS
All diagnostics are operated in the order and for the time duration specified for the appropriate PDP-12 machine
configuration. If a machine configuration is not standard, then the appropriate diagnostics for the option are
supplied; these programs are run for the amount of time indicated for the PDP-12 System.

B-1

A diagnostic program tape and write-up are included with any standard or special option. A standard option is an
option supplied by DEC but not included as a basic option of a PDP-12 System (e.g., a line printer). Special options are defined as hardware designed from customer specifications to fulfill a specific requirement, or standard
option that is modified in any way. An acceptance procedure and accessory checklist are provided for such options. The installation information includes the interfacing of the option to the PDP-12.
The acceptance procedure outlines the programs to be run and the time duration for acceptance of the option.
The accessory checklist contains a list of all manuals, prints, programs, etc., that are normally supplied with the
option.
Consult the appropriate diagnostic write-up for operating procedures and correct operation indications.
8.5 SYSTEM SOFTWARE ACCEPTANCE
The system software acceptance is provided in a system acceptance document for the appropriate PDP-12 System.
Each document is designed to demonstrate the operation of the system software for the particular configuration,
to exercise the machine to its fullest capabilities, and to use the various routines supplied in the software.

NOTE
All PDP-12 programs have been previously checked and
certified as being error free.
Successful completion of Sections B.4 and 8.5 shall constitute system acceptance. Discrepancies must be listed
as "exceptions" on the Customer Acceptance Form.

B-2

APPENDIX C
FORMS AND CHECKLISTS

A large envelope, enclosed with the PDP-12 Accessory Kits, contains the following items:
a.

Customer Acc\ptance Forms

Key Sheet

Customer Data Forms

Software Trouble Reports

DECUS Information

Basic Accessory Checklists

Optional Equipment Checklists

Software Checklists

Final Distribution Lists

Each of the items listed is discussed in the following paragraphs. The sole intent of this information is to produce
uniformity in customer acceptance procedures.
C. l CUSTOMER ACCEPTANCE FORMS
The Customer Acceptance Forms are logged at DEC in Maynard, Massachusetts, prior to equipment acceptance.
The form lists the equipment items that are included in the shipment. The customer name, the DEC installation
code, the DEC order number, and the customer purchase orders are also included on the form. Personnel installing the equipment must check the keyed equipment serial numbers listing against the serial number on the equipment and enter the serial numbers in the appropriate column on the Customer Acceptance Form. All serial
numbers, including those on vendor-supplied material, are verified in this manner.
All future PDP-12 System additions, modifications, and inquiries are solely dependent on the accuracy of the Key
Sheet, which lists all system components by model and serial number, and the Acceptance Forms. Upon successful completion of acceptance testing, any "exceptions" are listed in the appropriate section on the Customer
Acceptance Form. The "exceptions" should include missing manuals or prints and any hardware, etc., that was
not acceptable.
C.2 CUSTOMER DATA FORMS
The Customer Data Form is used to establish an accurate mailing list and customer contact file. The form should
be completely filled out and the appropriate copy returned to DEC's Field Service Organization in Maynard,
Massachusetts.

C-1

C.3 SOFTWARE TROUBLE REPORTS

Software Trouble Reports enable the customer to communicate directly with the DEC Software Group. Any
software problems should be described in detail and, if possible, examples attached.
C.4 DECUS INFORMATION

The DECUS information and introductory l~tter familiarizes the user with the Digital Equipment Computer Users
Society. The letter invites membership and includes application forms.
C.S BASIC ACCESSORY CHECKLIST

The Basic Accessory Checklist contains an accurate list of all items that are normally supplied with the basic
PDP-12. DEC personnel check each item on this list with the customer, and the customer then signs the complete
form. The appropriate copy is then returned to DEC in Maynard, Massachusetts. The remaining copies should be
distributed as indicated on the bottom of the form. Specified items that are not included should be listed as
"exceptions" on the Customer Acceptance Forms.
C.6 OPTIONAL EQUIPMENT CHECKLIST

Accessory checklists for each option are supplied. The Basic Accessory Checklist procedures apply.
C.7 SOFTWARE CHECKLIST

The Software Checklist enclosed has been checked at the factory and is rechecked with the customer. Any items
missing should be listed as "exceptions". This form is also signed by the customer and returned to DEC in
Maynard, Massachusetts; Requests for additional copies of programs should be submitted to the DEC Program
Library.
C.8 FINAL DISTRIBUTION OF FORMS

The return-addressed envelope is sent to DEC in Maynard, Massachusetts with the following completed forms:

Customer Acceptance Forms

Customer Data Forms

Basic Accessory List

Optional Equipment Checklist

Software Checklist

Installation Report

Final Distribution Lists

All of the items above, except b. and f, require the customer's signature. Only items listed as "exceptions" are
replaced at no cost. All other items must be substantiated by a Customer Purchase Order.
A complete set of prints is supplied with the PDP-12 System. The Key Sheet should be used to reference the
Master Drawing List (MDL) for each subsection (1/0, CP, MEMORY) or option in the PDP-12 System. Wire lists,
parts lists, and mechanical assembly prints are not supplied with any print set. These may be obtained only by
special order.

C-2

APPENDIX D
SOFTWARE AND PREWIRED OPTION DIAGNOSTICS

The following is a list of PDP-12 Software, designating exactly what tapes and write-ups are involved in the
PDP-12 Software Kit. Included also is the list of MAINDECs for the Prewired Options. Also included is a list of
the programs available on the LINCtapes (Pages D-5 - D-11). For a complete discussion of user programs available on the PDP-12, refer to Chapter 7 of PDP-12 System Reference Manual (DEC-12-SRZA-D) (note that later
revisions may be shipped).
PDP-12 SOF1WARE
NOTE
-D Document
-ON Document Change Notice
-PA Paper Tape ASCII
-PB Paper Tape BINARY
-PM Paper Tape READ-IN-MODE
-UO LINCtape
LINC-8 PROGRAMMING MANUAL
PROGRAMMING LANGUAGES
INTRODUCTION TO PROGRAMMING
LOGIC HANDBOOK
FORMS AND CHECKLIST ENVELOPE
GETTING ON THE AIR WITH YOUR PDP-12
LINCTAPES (see Pages A-9 - A-15)
LAP6-DIAL USER PROGRAMS

DEMO PROGRAMS
MAINTENANCE PROGRAMS

I-L85

DEC-12-SE2D-UO
DEC-l 2-SE3A-UO
DEC- l 2-SE4A-UO
DEC-l 2-SE5A-UO
DEC-12-UXZA-UO
DEC-12-MRZA-UO
MAINDEC- l 2-D7 AC-UO
MAINDEC-l 2-D8GA-UO

PDP-12 SIGNAL PROC. MANUALS
CAT ACAL
CATACAL ADDENDUM
ADTAPE AND ADCON
TISA
SI NP RE

DEC-12-UWlA-D
DEC-12-UWl A-DL
DEC- l 2-UW2A-D
DEC- l 2-UW3A-D
DEC-l 2-UW4A-D
DEC-12-UW5A-D
DEC-12-UZSA-D
DEC-12-UZ 1A-D

MAG SPY
SIGNAL AVERAGER USER'S GUIDE

(continued on next page)
D-1

PDP-12 SYSTEMS-DEMO MANUALS
PDP-12 SYSTEM REFERENCE MANUAL
LAP6-DIAL MANUAL
FRED
MILDRED
CONVERT
LINC-8 SIMULATOR TRAP PROCESSOR
MARK12-A
PATCH
CREF12
PRTC12-F
DEMO 12 USER'S GUIDE
DEMO 12 USER'S GUIDE ADDENDUM
DEMO 12 MONITOR SYSTEM TECHNICAL REFERENCE
MANUAL

DEC-12-SRZA•D
DEC- l 2-SE2D-D
DEC-12-FISA-D
DEC-12-FZFA-D
DEC-12-FZDA-D
DEC-12-ESYB-D
DEC-12-SI 1B-D
DEC-12-YlTA-D
DEC-l 2-YU2A-D
DEC-12-FRZA-D
DEC-12-YIY A-D
DEC-12-UXZA-D
DEC-12-UXZA-DN
DEC-12-MRZA-D

PDP-8 SYSTEM SOFTWARE
SOFTWARE PERFORMANCE SUMMARY
SYSTEM USER'S GUIDE
DDT
DDT CHANGE NOTICE
ODT-8
SYMBOLIC EDITOR
SYMBOLIC EDITOR CHANGE NOTICE
BINARY LOADER (TWO COPIES)
"HELP" LOADER
READ-IN-MODE LOADER
4K FORTRAN
READ-IN-MODE (RIM) PUNCH
BINARY PUNCH
OCTAL MEMORY DUMP

VOLUME 2: #3
DEC-08-NGGC-D
DEC-08-CDDB-D
DEC-08-CDDB-DN
DEC-08-COCO-D
DEC-08-ESAB-D
DEC-08-ESAB-DN
DEC-08-LBAA-D
DEC-08-LHAA-D
DEC-08-LRAA-D
DEC-08-AFCO-D
DEC-08-PMPO-D
DEC-08-YXYA-D
DEC-08-YPPA-D

PDP-12 MAINTENANCE MANUALS
PDP-12 CP TEST 2 (SKIP AND DATA HANDLING)
INSTRUCTION TEST PART 1
PDP-12 CP TEST 3
JMP SELF .
PDP-12 CHECKERBOARD
FLOAT 1'S & O'S THROUGH MEMORY
PDP-12 TAPE CONTROL TEST (PART 1of2)
VR12 DISPLAY TEST
A TO DTEST
PDP-12 RELAY REGISTER TEST
PDP-12 OPERATING PROCEDURE

MAINDEC-12-DOAB-D
MAINDEC-12-DOBA-D
MAINDEC-12-DOCA-D
MAINDEC-12-D 1BA-D
MAINDEC-12-D 1DA-D
MAINDEC-12-D 1EA-D
MAINDEC- l 2-D3AE-D
MAINDEC-1 2-D6BA-D
MAINDEC- l 2-D6CB-D
MAINDEC- l 2-D8AB-D
MAINDEC- l 2-D9CA-D

INSTRUCTION TEST 1
INSTRUCTION TEST 2

MAINDEC-81-DOl C-D
MAINDEC-81-D02B-D

PDP-8 INSTRUCTION TEST PART 2B
RANDOM JMP TEST
RANDOM JMP-JMS TEST

MAINDEC-08-D02B-D
MAI!'IDEC-08-D04B-D
MAINDEC-08-DOSB-D

(continued on next page)

D-2

RANDOM ISZ TEST
MEMORY ADDRESS TEST
BASIC PDP-8, 8/1 MEMORY CHECKERBOARD
PDP-8 MEMORY POWER ON/OFF TEST
FAMIL Y-OF-ASR 33/35 TELETYPE TESTS PART 1
FAMILY-OF-ASR 33/35 TELETYPE TESTS PART 2

MAINDEC-08-D07B-D
MAINDEC-08-D 1BO-D
MAINDEC-08-D 1LO-D
MAINDEC-08-D 1AC-D
MAINDEC-08-D2PE-D
MAINDEC-08-D2QD-D

PDP-12 SYSTEM TAPES
FORTRAN COMPILER
FORTRAN SYMBOL PRINT
FORTRAN OPERATING SYSTEM
SAMPLE PROGRAM FORTRAN SYM DESK CALCULATOR

DEC-08-AFC I -PB
DEC-08-AF A2-PB
DEC-08-AFC3-PB

FOCAL, 1969 & INIT 4K INIT
UTILITY OVERLAYS FOR FOCAL, 1969 (4 WORD, 8K)

DEC-08-AJAE-PB
DEC-08-AJ 1E-PB

PAL III
PAL III EXTENDED SYMBOLS

DEC-08-ASC I -BP
DEC-08-ASC2-P A

DDT-8
MACR0-8 LOW SPEED

DEC-08-CDDB-PB
DEC-08-CMA I -PB

ODT(LOW)
ODT (HIGH)

DEC-08-COC I -PB
DEC-08-COC2-PB

SYMBOLIC EDITOR

DEC-08-ESAC-PB

BINARY LOADER (2 COPIES)

DEC-08-LBAA-PM

HELP BOOTSTRAP LOADER
HELP GENERATOR

DEC-08-LHA I -PB
DEC-08-LHA2-PB

READ-IN-MODE (RIM) PUNCH
LOW MEMORY -33
HIGH MEMORY RIM PUNCH -33

DEC-08-PMP 1-PB
DEC-08-PMP2-PB

OCTAL MEMORY DUMP
BINARY PUNCH-TELETYPE (ASR-33)

DEC-08-YPP A-PB
DEC-08-YX 1A-PB

PDP-8 FLOATING POINT PACKAGE
PACKAGE I : BASIC PACKAGE (BASIC 1/0 PLUS
INTERPRETER
PACKAGE 2: BASIC PACKAGE PLUS CONTROLLER
PACKAGE 3: BASIC PAC KA GE PLUS EXTENDED FUNCTIONS
PACKAGE 4: BASIC PACKAGE PLUS CONTROLLER &
EXTENDER FUNCTIONS

DEC-08-YQI B-PB
DEC-08-YQ2B-PB
DEC-08-YQ3B-PB
DEC-08-YQ4B-PB

PDP-12 DIAGNOSTICS
PDP-12 CP TEST 2 (SKIP AND DATA TEST)
INSTRUCTION TEST I
CP TEST III
JMP SELF
PDP- I 2 CHECKERBOARD
FLOAT I'S and O'S THROUGH MEMORY
TAPE CONTROL TEST

MAINDEC- I 2-DOAB-PB
MAINDEC- I 2-DOBA-PB
MAINDEC-1 2-DOCA-PB
MAINDEC- I 2-D 1BA-PB
MAINDEC- I 2-D 1DA-PB
MAINDEC-12-D 1EA-PB
MAINDEC-12-D3AE-PB

(continued on next page)

D-3

DISPLAY TEST (VR 12)
A-TO-D TEST
DR12 RELAY REGISTER TEST

MAINDEC-12-D6BA-PB
MAINDEC-l 2-D6CB-PB
MAINDEC-l 2-D8AB-PB

INSTRUCTION TEST 1
INSTRUCTION TEST 2

MAINDEC-81-DO IC-PB
MAINDEC-81-D02B-PB

INSTRUCTION TEST PART 2B

MAINDEC-08-D02B-PB

RANDOM JMP TEST

MAINDEC-08-D04B-PB

RANDOM JMP-JMS TEST
RANDOM ISZ TEST
PDP-8 MEMORY POWER ON/OFF TEST
MEMORY ADDRESS TEST (LOW)
MEMORY ADDRESS TEST (HIGH)
BASIC PDP-8, 81 BASIC MEMORY CHECKERBOARD (LOW)
BASIC PDP-8, 81 BASIC MEMORY CHECKERBOARD (HIGH)
FAMILY OF 8 ASR 33/35 TELETYPE TEST PART 1
FAMILY OF 8 ASR 33/35 TELETYPE TEST PART 2
TAPE CONTROL TESTS PART I
PART2

MAINDEC-08-D05B-PB
MAINDEC-08-D07B-PB
MAINDEC-08-D I AC-PB
MAINDEC-08-D I BI -PM
MAINDEC-08-D I B2-PM
MAINDEC-08-D I LI -PM
MAINDEC-08-D I L2-PM
MAINDEC-08-D2PE-PB
MAIN DEC-08-D2QD-PB
MAINDEC- l 2-D3AC-PB
MAINDEC- l 2-D3AC-D

Table D-1
Options Diagnostics
Option and Program Name

Mnemonic

DEC Number

Use

PDP-12 Extended Memory
Control

EXTMC12
writeup

DEC-12-D I AC-PB
DEC-12-D I AC-D

Tests Control Logics
for Extended Memory

Extended Memory
Control (81)

EXTMC
writeup

DEC-08-D I CA-PB
DEC-08-D I CA-D

Tests Control Logics
for Extended Memory

Extended Memory
Checkerboard

EXTCB
writeup

DEC-08-D I DA-PB
DEC-08-DIDA-D

Tests Extended Memory
Stacks for noise

Extended Memory
Address Test
KW12-B-C

EXTAT
writeup
clock

DEC-08-D I HA-PB
DEC-08-D IHA-D
DEC- l 2-D8EA-PB

Tests Addressing for
Extended Memory Stacks

KW12
Clock Control test

KW12 D8CB
writeup

DEC- l 2-D8LB-PB
DEC- l 2-D8CB-D

Tests all lgoic for
KW12

Calcomp 1

Calcomp
writeup

DEC-08-D6CB-PB
DEC-08-D6CB-D

Plotter Test

Calcomp 2

OCALCOMP
writeup

DEC-08-12-U-PA
DEC-08-12-U-D

Plotter subroutine
Tests

EAE3A
writeup

DEC-08-DOAA-PB
DEC-08-DOAA-D

Tests Extended
Arithmetic Control
logic

EAE3B
writeup

DEC-08-DOBA-PB
DEC-08-DOBA-D

More extensive test
• of EAE Control logic

MC12

KE12
EAE Test, Part 3A

EAE Test, Part 3B

(continued on next page)

D-4

Table D-1 (Cont)
Option Diagnostics
Use

Mnemonic

DEC Number

FOCAL4K
writeup

DEC-08-AFLO-D

FOCAL using 4K of
Memory

FOCAL8K

FOCAL8K
writeup

DEC-08-KFXB-PB
DEC-08-KFXB-D

FOCAL using 8K of
Memory

KP12

PNRFAIL
writeup

DEC-08-DIK I -PB
DEC-08-D I K 1-D

Tests ability to retain
and restart program after
power failure

KT12

Option test
writeup
writeup
Hard ware test
Monitor Man.

DEC-T8-D8AA-PB

Option and Program Name
FOCAL
FOCAL 4K

DEC-08-AFCO~PB

DEC-T8-D8AA-D
DEC-T8-D8BB-D

DEC-T8-D8BB-PB
DEC-T8-MRFB-D

)

Tests Time Sharing
System control logic
and hardware

Teletype tests
writeup

DEC-08-D2AA-PB}

DPI 2-B

PT08 Test
writeup

DEC-08-D8P A-PB
DEC-08-D8PA-D

Extended Tape
Control

PRTC12-F

DEC-12-YIYA-UO

Tape Conversion Test

Extended Tape
Control

TCV12-F

DEC- l 2-D3EA-PB

Tests TC 12-F logic

TC 12-F writeup

Program
Diagnostic

DEC-12-YIY A-D
DEC- l 2-D3EA-D

DP12-A

DEC-08-D2AA-D

Tests Dataphones
control logic and
punch and read logic

User Programs
DEC- l 2-SE2D-UO
Name
PIP
L8SIM
DIAL-MS
MAG SPY
MARK12
PATCH
PRTCl 2-F
CONVERT
DIAL V2
DIAL-MS4
DIAL-MS3
DIAL-MS2

Binary

Source
BN

BLKS

470
246
504
171
542
566
142
245

14
I
36
47
24
65
27
1

BLKS

247

656

122
114
74

20
6
20
(continued on next page)

D-5

DEC-12-SE2D-UO (Cont)
Name
DIAL-MSl
GENASYS
CATACAL
SIGAVG
SINPRE
CNTRL2
CNTRL4
DIALMS

Binary

Source
BLKS

711
16
653
12
11

BLKS

54
240
665

20
5
21

65
36
3
4
1

DEC-12-SEJA-UO
Name
PIP
MARK12
FOCAL4K
FOCAL8K
L8SIM.
QANDA
CONVERT
MAGS PY
DIALV2
FORCOM
FRED
FORSYS
BINLOAD
PATCH
PRTC12-F
FMAA-PA
FM8A-PA
FMC8-PA
FMDA-PA
FMEA-PA
FMFC-PA
FMGB-PA
FMHA-PB
FMIA-PA
FMJA-PA
FMKA-PA
IOUASCII
l lUASCII
15UASCII
14UASCII
21-U-BIN
21 UASCII
19UASCII
18UASCII

Binary

Source
BN

BLKS

173
172

1
1

534

226
206
702
205
201

1
1
40
1
1

530
176
573
577
145
607
142

2
3
4
10
7
10
3

227
626
532
212
631
635
112

1
3
2
1
4
5
4

645
107
103

5
3
4

BLKS

247
470
477
116
207
213
520
216

21
7
21
22
3
3
5
10

553
525
154
202
243
230

20
3
16
3
4
12

617

642

(continued on next page)

D-6

DEC-12-SE3A-UO (Cont)

Name
22UASCII
23UASCII
24UASCII
29UASCII
25UASCII
28UASCII
MILDRED
YQIA-PB
YQ2A-PB
YQ3A-PB
YQ4A-PB
25F-EAEI
25F-EAE2
25F-EAE3
25F-EAE4

Binary

Source
BN

BLKS

652
76
655
64
663
673

3
5
6
12
10
7

BLKS

742
20
11
0
745
55
45
35
756

3
7
7
11
11
7
7
11
11

DEC-l 2-SE4A-UO

Name
ADTAPE
ADCON
SIGAVGl
SIGAVG2
SIGAVG4
NM RS IM
NMR2
NMR3
CAT2
CAT3
SINPRE
CATIE
CATI

Binary

Source
BN

BLKS

6
470

71
46

252

242
232
220
536

10
10
12
20

715
727
736

12
7
7

40
52
61
65

160
556
77
630

DEC-12-SESA-UO

Name
. TISA
TIPl
TIP2
MILDRED
NMRSIME
CATACALE

Binary

Source
BN

BLKS

470
173
563

73
55
35

BLKS

250

153
132

20
21

(continued on next page)

D-7

Demonstration Programs
DEC-12-UXZA-UO
Name
LOADER.
SEGOl-3.
SEGl 1-4.
INITLIZ.
GREETIN.
BALLOON.
SEG04-4.
DMOINDX.
QANDA.
.DA-DTST
.DDATA12
.DMAGSPY
.DFRQANA
.DDIAL
.FFREQ12
.EWAVES
.EB.BALL
.EBASMEM
.FSOLACE
.FMUSIC
.FKALEID
.FDRAW12
.FECHASK
.FSPCWAR
.TDAYCOM
.TSTPWCH
.TCLOCK
SCRATCH.
GREETING
INDEXSRC
DIAL-V2
MARK12
PIP
EX.PROG.
AD DEMO
BINLOAD
L8SIM
CONVERT
FOCAL8K
FOCAL4K
CAROLS
LOADER
INITLIZE
SEGO
SEGl
BALLOON
04-01-70

Binary

Source
BN

BLKS

24
24
32
35
45
46
50
52
53
54
55.
56
57
61
63
66
67
71
103

2
4
2
2
1
2
2
1
1
1
1
1
2
2
3
1
2
1
50

263
522

5
2

526
527

1
1

635
641
663
725

2
17
34
36

527

BLKS

0
1
4
10
11
12
17
20
22
165
37
153
72
163
170
173
176
201
206
210
216
220
223
226
244
250
256

1
3
4
1
1
5
1
2
2
3
6
10
11
2
3
3
3
5
2
6
2
3
3
16
4
6
5

776

511
470
520
614
535
540
543
550
573
617
637
660
717
763
771

7
21
2
3
3
3
5
23
21
11
2
3
7
6
5

(continued on next page)

D-8

DEC-12-MRZA-UO
Name
OMAGSPY
DRAWI2
KALIED
REMAKE
BALLOON
H-DIAL
H-FRQANA
H-FREQ12
H-B.BALL
H-ECHASK
H-DAYCOM
H-STPWCH
H-DRAW12
H-SOLACE
H-CLOCK
H-BASMEM
H-MAGSPY
H-A-DTST
DATA12
ECHASK
H-DATA12
MARK12
PIP
EX.PROG.
AD DEMO
KW12SUBC
LOADER
INITLIZE
SEGO
SEGl
STPWCH
FRO ANA
INDEXSRC

Source

Binary

BLKS

160
540
520

37
6
l

BLKS

141
507

17
5

127
470

7
17

557
546
613
551

2
3
6
6

l
2
2
l
2
l
l
2
l
l
l
2
1
17
3
3

514
515
521
517
523
527
530
531
533
534
561
137
136
244
535
621

525
526
630
635
102
637
44
217
562
263

l
l
5
2
17
34
36
25
31
5

Maintenance Programs
DEC-12-07 AC-UO (basic diagnostics)
Name
PIP
MARK12
RIMLDR
BINLDR
CBL
CBH
ADD RS LO

Source

Binary

BLKS

604
603
605
606
607
104
612

l
l
l
l
l

251
470
477
502
505
245
510

17
7
3
3
3
4
3

(continued on next page)

D-9

DEC-12-D7AC-UO (Cont)
Name
ADDRSHI
ADDRS12
RANISZ
RANJMP
JMPJMS
JMPSELF
MEMDATA
INSTI
INST2
INST2A
INST28
EAE3A
EAE38
CPTSTI
CPTST2
CPTST3
TTYl

TTY2
TC12F
DP12A
PWRFAIL
EXTMC
EXTAT
EXTCB
EXTMC12
TAPECNTL
ADTST
RELAYTST
DISPTST
KW12TST
KW12BC
ONOFF
CALCOMP

Binary

Source
BN

BLKS

103
611
101
102
100
610
613
614

1
1
1
1
1
1
1

4
2
5
4
4
2
2
13
12
14
6
15
14
4
21
15
7
13
10
14
3
6
10

I
I

241
513
515
235
522
233
231
526
217
203
541
547
167
564
146
131
570
615
121
630
577
113
644
654
107
56
66S
672
676
46
702
707
36

BLKS

42
41
37
40
250
147
15S
IS4
ISO

1
1
1
1
1
1
1

251
470
477
S02

17
7
3
3

726
602
106
105
712
713
725
714
715
30
27
716
717
720
721
35
722
34
723
33
724
727
32
31

1
1
1
I

1
1
1
1
1
1
1
1
1
1
1
1
1
I

1
1
1

4
21
5
4
4
10

s
3

DEC-12-D8GA-UO (option diagnostics)
Name
PIP
MARK12
RIMLDR
BINLDR
DB12
DC02
DC04
HS RD PUN
DF32DD

Binary

Source

sos

242
Sl2
230
S23

6
11

12·
21
(continued on next page)

D-10

DEC-12-DSGA-UO (Cont)
Name
DF32DL
RF08DD
RF08MD
LINEPNTR
CARD READ
PECITRE
PECITIT
PECITDRT
PECITDT

Source

Binary

BLKS

153
604
152
605
151
146
145
144
143

I
I
I
I
I
I
I
I
I

216
203
544
177
557
170
565
156
576

12
13
13

D-11

6
7
11
12
6

INDEX

Acceptance
Customer Programs, B-1
Diagnostics, B-1
Software, B-2
Forms, Customer, C-1
Testing, B-1
Acoustical Damping, 1-4
A/D Adjustments, 3-30
A/D Sample & Hold Adj., 3-30
Adjustments, Chapter 3, 3-1
Memory Current & Strobe, 3-1
Air Conditioning, 1-4
Analog Adj., Extended, 3-33
Analog and Display Adj. & Checks, 3-26
Analog Channel Adj., External, 3-32

B
BIN, Loading, 1-1 7

D/ A (AD 12) .Adj. & Checks, 3-26
D/A Adj. Procedures, 3-27
Daily Maintenance, 2-4
Data Forms, Customer, C-1
DECUS Information, C-2
Demonstration Programs, List, D-8
Depot Repair, A-2
Diagnostics
Memory, 3-8
Prewired Option Software List, D-1
Display
Brightness & Preset Adj., 3-29
Size & Position Adj., 3-29
(VR12) Adjust. & Checks, 3-26
DM12
Checkout, 4-25
Installation, 4-14
DP 12-B Checkout, 4-22
E

c
Cabinet
Installation, 1-13, 1-5
Inspection, 1-13
Unpacking, 1-12
Cabling, 1-11
Checklist, Software, C-2
Checkout, 1-15
Checks
Console, 2-7
8-Mode Processing, 2-9
LINC-Mode Processing, 2-8
TC12 Console, 2-10
TC12 Tape Subprocessor, 2-9
Circuit Breaker CB 1, 1-15
Cleanliness, 1-5
Configurations, System, 1-5
Console Checks, 2-7
Constraints, Installation, 1-4
Corrective Maintenance, 2-5
Teletype, 5-3
Customer Acceptance, B-1

8-Mode Processing, 2-9
Environmental Consideration, 1-4
Equipment
Checklists, Optional, C-2
Maintenance, 2-1
Expanded Equipment Layout, 1-7
Expansion, System, 1-6
Extended Analog Adj. (AG12, AM12), 3-33
Extended Memory MC 12 Adjustments, 3-7
External Analog Chan. Adj., 3-32

F
Fire and Safety Precautions, 1-3
"Floating" Signals, 2-2
Floor Construction, Planning, 1-1
Floor Plan Requirements, 1-7
Forms, Distribution of, C-2
Forms & Checklists, C-1
H

Humidity, 1-4

INDEX (Cont)

I
1/0 Interface, 1-6
Initial Memory Current Adjustments, 3-1
Initial Strobe Adjustments, 3-2
Inspection
Cabinet, 1-13
Peripheral Equipment, 1-15

Installation, 1-1
Cabinet, 1-13
Options, 1-15
Prewired Options, 4-1
Teletype, 1-14
Constraints, 1-4
K

KF12-B
Checkout, 4-25
Installation, 4-14
L

LAP6-DIAL Maintenance, 3-29
LAP6-DIAL MAINTENANCE Tapes, Mounting, 2-3
Lighting, 1-4
LINC-Mode Processing, 2-8
LINCtape
ACIP Delay Adj., 3-14
Adjustments, 3-9
LTD Tape Fail Delay Adj., 3-13
LTD TTOK Delay Adj., 3-12
LTD XTLK Delay Adjustments, 3-11
System Checkout, 4-15
Loading
BIN, 1-17
RIM Loader, 1-16
Log Book, 2-14
Logic Troubleshooting, 2-12
M

MAINDECs, Loading, 1-17
Maintenance, Chapter 2, 2-1
Corrective, 2-5
Daily, 2-4
LAP6-DIAL, 3-29
Preventive, 2-3
Scheduled, 2-4

Weekly, 2-4
Service Options, A-1
Equipment, 2-1
Programs, list of, D-9
Programs, Teletype, 5-2
Tasks, Preventive, 2-4
Test Programs, 2-2
Tools, Teletype, 5-1
Mark Clock Adj., 3-16
Memory
Current Adjustments, Initial, 3-2
Current Adjustments, Final, 3-4
Current and Strobe Adjustments, 3-1
Diagnostics, 3-8
Extended, Adjustments, 3-7
Margins & Final Strobe Adjustments, 3-6
Strobe Adjustments, 3-2
Tests, 1-16
Module Troubleshooting, 2-12
Mounting LINCtape, 2-3

0
Operating Checks, Preliminary, 1-15
Option
Checkout, 4-14
Installation, 1-15
Module and Cable List, 4-3
Optional Equipment Checklists, C-2
Options
DEC Field Installation, A-3
MAINDEC list, 4-1
p

Packing Details, 1-8
Panels & Cables, Installation of, 4-6
Pedestal Type Flooring, 1-1
Peripheral Inspection, 1-15
Planning, Installation, 1-1
Power
Cable Line Identification, 1-11
Cabling, 1-11
OK Adjustment, 3-6
Receptacle Part Numbers, 1-10
Receptacles, 1-10
Requirements, Source & System 1-9
Supply Specifications, 2-5
Predelivery Preparation, 1-6

INDEX (Cont)

P (cont)
Preliminary Operating Checks, 1-15
Preparation, Predelivery Procedures, 1-6
Preventive Maintenance, 2-3
Teletype, 5-2
Tasks, 2-4
Prewired Options
Installation, 4-1, 1-15
Software Diagnostics, D-1
List of, 4-1
Unpacking, 4-1
Checkout, 4-14
Printer/Punch Corrective Maintenance, 5-5
Programs
Customer, B-1
Demonstration list of, D-8
Maintenance list of, D-9
Maintenance Test, 2-2
User list of, D-5
R

Raceway Type Flooring, 1-2
Receiving Constraints, 1-8
Receptacles, Power, 1-10
Repairs & Replacements, 2-13
Requirements, Power, 1-9
RIM Loader, Loading, 1-16
Running MAINDECs, 1-17

s
Safety and Fire Precautions, 1-3
Scheduled Maintenance, 2-4
Service Contracts
Depot Repair, A-2
Eligibility, A-2
Options, A-1
Per-Call Coverage, A-2
Service Outlets, AC, 1-11
Shipping ·and Receiving Constraints, 1-8
Shipping Methods
Domestic & North America, 1-8
Overseas & Air Freight, 1-9
Site Considerations, Planning, 1-1
Software
Acceptance, B-2
Prewired Option Diagnostics, D-1

Checklist, C-2
Trouble Reports, C-2
Soldering Techniques, 2-14
Source Power Requirements, 1-9
Space Requirements, 1-1
Special Moun ting Considerations, 1-4
Specifications, Power Supply, 2-5
Standard Configurations, 1-5
Strobe ft_djustments, 3-2
System
Configurations, 1-5
Expansion, 1-6
Layout, Planning, 1-3
Power Requirements, 1-9
Troubleshooting, 2-6
T

f ape Timing Pulses Adjustment, 3-9
fC 12-F Checkout, 4-15
rc12
Console Checks, 2-10
Tape Subprocessor Checks, 2-9
feletype
Clock Adjustments, 3-8
Console Installation, 1-14
Corrective Maintenance, 5-3
Equipment, 5-1
Installation, 1-14
Keyboard Spares, 5-6
Maintenance, 5-1
Maintenance Programs, 5-2
Maintenance Tools, 5-1
Preventive Maintenance, 5-2
Replacement Parts, 5-5
Test, 1-16
Unpacking, 1-14
Temperature, 1-4
Test Programs, Maintenance, 2-2
Tests,
Computer Memory, 1-16
Teletype, 1-16
Validation, 2-14
Trouble Reports, Software, C-1
Troubleshooting
Logic, 2-12
System, 2-6
Modules, 2-12
Techniques, 2-6

INDEX (Cont)

T (cont)
TU55
Brake Adj., 3-18
Head Installation, 3-22
Head Removal, 3-22
Head Skew Adj., 3-22
Interconnections, 4-10
Stop Delay Adj., 3-21
Stop Torque Adj., 3-19
Tape Transport Adj., 3-17
Torque Adj., 3-19
Trailing Torque Adj., 3-20
Transport Head Replacement Adj., 3-21
Unit & Cable Installation, 4-8
TU56
Brake Adjustment, 3-24
· LINCtape Transport, 3-24
Oscillator Adj., 3-26
Unit & Cable Installation, 4-11

u
Unpacking
Installation & Inspection, 1-12
Teletype, 1-14
User Program List, D-5

v
Validation Tests, 2-14
VR12
Brightness & Preset Adj., 3-29
Checkout, 4-1 7
Deflection Adj., 3-30
Display Focus Adj., 3-30
Size & Position Adj., 3-29
Unit and Cable Installation, 4-8
VR14, 3-26, 4-25

w
Weekly Maintenance, 2-4