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DEC-12-HR2A-D

December 1971

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DEC-12-HR2A-D

PDP-1

MAINTENANCE MANUAL

VOLUME

INSTALLATION AND MAINTENANCE

DIGITAL

EQUIPMENT

CORPORATION

•

MAYNARD, MASSACHUSETTS

The material
tion purposes

this manual is for informaand is subject to change with-

out notice.

The following are trademarks of Digital Equipment
Corporation, Maynard, Massachusetts:

DEC

PDP

FLIP CHIP

FOCAL
COMPUTER LAB

DIGITAL

CONTENTS
Page

CHAPTER 1 INSTALLATION
1.1

Planning

1-1

1.1.1

Site Considerations

1-1

1.1.2

Space Requirements

1-1

1.1.3

Floor Construction

1-1

1.1.4

System Layout

1-3

1.1.5

Fire and Safety Precautions

1-3

1.1.6

Installation Constraints

1-4

1.1.7

Environmental Considerations

1-4

1.2

System Configurations

1-5

1.2.1

Standard Configurations

1-5

1.2.2

System Expansion

1-6

1.2.3

I/O Interface

1-6

1.3

Predelivery Preparation

1-6

Preliminary Procedures

1-6

1.3.2

Shipping and Receiving Constraints

1-8

1.3.3

System Power Requirements

1-9

1.3.4

Source Power Requirements

1-9

1.3.5

Primary ac Power Cables

1-11

1.3.1

1.3.6

Service Outlets

1.3.7

Cabling

1-11

1.4

Unpacking, Installation and Inspection

1-12

1.4.1

General

1-12

1.4.2

Cabinet Unpacking

1-12

1.4.3

Cabinet Installation

1-13

1.4.4

Cabinet Inspection

1-13

1.4.5

Teletype Unpacking

1-14

1.4.6

Teletype Installation and Setup

1-14

1.4.7

Prewired Option Installation

1-15

1.4.8

Peripheral Equipment Inspection

1-15

1.4.9

Miscellaneous Items

1-15

1.5

Checkout

1-15

1.5.1

Preliminary Operating Checks

1-15

1.5.2

Teletype Test

1-16

1.5.3

Computer Memory Test

1-16

1.5.4

RIM Loader

1-16

1.5.5

Running MAINDECs

1-17

CHAPTER 2 MAINTENANCE
2.1

Introduction

2-1

2.2

Maintenance Equipment

2-1

iii

CONTENTS (Cont)
Page
Z.Z. 1

Maintenance Test Programs

2-2

2.2.2

Mounting DIAL MAINTENANCE Tapes

2-3

2.3

Preventive Maintenance

2-3

i ^ i
2.3.1

Scheduled Maintenance

2-4

2.4

Corrective Maintenance

2-5

Z.4.1

Preliminary Investigation

2-6

A ^
2.4.2

System Troubleshooting

2-6

Troubleshooting Techniques

2-6
2-6

**i

Z.J. 1

Introduction

O
C I
Z.j.z

Console Checks

o c o
2.5.3

T TXT/""
~ ~
~
LINC-Mode
Processing

2-8

2.5.4

8-Mode Processing

2-9

2.5.5

TCI 2 Tape Subprocessor

2-9

2.5.6

TCI 2 Console Checks

2-10

2.5.7

Logic Troubleshooting

2-12

2.5.8

Module (Circuit) Troubleshooting

2.5.9

Repairs and Replacements

2.5.10
2.5.11

TV /T

~T\

2-7
1

1 o
Z-13

A
z-14

Validation Tests

Log Book Recording

^
1 A
2-14

CHAPTER 3 ADJUSTMENTS
3.1

Memory Current and Strobe

3-1

3.1.1

Initial Current Adjustments

3-1

3.1.2

Initial Strobe Adjustment

3-2

3.1.3

Memory Strobe Adjustments

3-2

3.1.4

Final Current Adjustments

3-4

3.1.5

Memory Margins and Final Strobe Adjustments

3-6

3.2

Power OK

3-6

3.2.1

Check Procedure

3-6

3.2.2

Adjustment Procedure

3-6

3.3

Extended Memory MCI

3-7

3.3.1

Set-up and Adjustment Procedure

3-7

3.4

Teletype Clock

3-8

3.5

LINCtape

3-9

3.5.1

Tape Timing Pulses

3-9

3.5.2

3-11

3.5.5

LTD XTLK Delay
LTD TTOK Delay
LTD TAPE FAIL Delay
LTD ACIP Delay

3.5.6

Mark Clock Adjustment

3-16

3.6

TU55 Tape Transport
TU55 Brake Adjustment
TU55 Torque Adjustments

3-17

3.5.3

3.5.4

3.6.1

3.6.2

3-12
3-13

3-14

3-18
3-19

CONTENTS (Cont)
Page
O

3.7

TU55 Transport Head Replacement and Adjustment Procedures
1U56 lape lransport

3.7.1

3.7.2

Oscillator Adjustment

3.6.3

3-21
O OA
3-14

O OA
3-14

U56 Brake Adjustment

3-26

3.8

Analog (AD 12) and Display (VR12,VC12)

3-26

3.8.1

Digital-to- Analog Adjustment Procedure (A615)

3-27

3.8.2

VR12 Size and Position Adjustments

3-29

3.8.3

Brightness and Brightness Preset Adjustment

3-29

3.8.4

Deflection Amplifier Quiescent Current Adjustment (VR12)

3-30

3.8.5

Analog-to-Digital Adjustment Procedure

3-30

3.8.6

Sample and Hold Adjustment Procedure (A404)

3-32

3.8.7

External Analog Channel Adjustment Procedure

3-32

3.9

Extended Analog (AGl2,AMl2)

3-33

3.9.1

Set-up Procedure

3-33

3.9.2

Adjustment Procedure

3-34

CHAPTER 4 FIELD INSTALLATION AND
CHECKOUT OF PREWIRED OPTIONS
4.1

Unpacking

A 1
4-1

4.2

Installation

4-2

4.2.1

Installation of Panels and Cables

4-6

4.2.2

Unit and Cable Installation for TU55 and VR12

4-8

4.2.3

TU56 Unit and Cable Installation

4-11

4.3

Checkout

A A
4-14

4.3.1

Checkout of the DPI 2-B

4-14

4.3.2

Checkout of TC12-F

4-15

4.3.3

Checkout of the LINCtape System

4-15

4.3.4

Checkout of VR12

4-17

CHAPTER 5 TELETYPE MAINTENANCE MODELS ASR 33 AND 35
5.1

Equipment

5-1

5.2

Preventive Maintenance

5-2

5.2.1

Weekly Tasks

5-2

5.2.2

Preventive Maintenance Tasks

5-2

5.3

Corrective Maintenance

5-3

5.4

Teletype Parts

5-5

APPENDIX A MAINTENANCE AND SERVICE OPTIONS
Service Contracts

A-1

A.1.1

Service Contract Options

A-1

A. 1.2

Eligibility for Service Contract Coverage

A-2

A.l

APPENDIX (Cont)
Page
A 9
r\.
Z.

A-2

A Q
rV.D

A-2

A.4

Field Installation of Additional DEC Options

A-3

APPFNDTX R riNTOMFR ACCFPTANOF
B.l

Special Customer Requirements

B.2

Customer Programs

B-l

B.3

Special Customer Acceptance Testing

B-l

B.4

Diagnostics

B-l

B.5

System Software Acceptance

13-2

B-l

APPENDIX C FORMS AND CHECKLISTS
C.l

Customer Acceptance Forms

C-l

C.2

Customer Data Forms

C-l

C.3

Software Trouble Reports

C-2

C.4

DECUS Information

C-2

C.5

Basic Accessory Checklist

C-2

C.6

Optional Equipment Checklist

C-2

C.7

Software Checklist

C-2

C.8

Final Distribution of Forms

C-2

APPFNPITY n

^OFTWARF ANH PRFWTRFH OPTTON HT AOlMfKTTr^

ILLUSTR ATIONS
Figure No.

Art No.

Page

Ppflp<;tal
A- ^UvOlHi Flooring
IKJyJ 1 11 lj-,
J.

10-0479

1-2

Rarewav Flooring

10-0478

1-2

1-3

PDP-1 2 Fxnandfd Fmiinmptit T avont

12-0255

1-7

1-4

Minimum PDP-1 2 Fnuinment Floor Plan Recmirements 12-0256

1-7

1-5

Parkins? Ofttails

1-8

1-1

Title

lhhpll Wall R
PPPnf'QpIp
tipptoi" Fiidcrfatn
X1UUUC11
JXCOCp
laV^lC f^nn
^LUIIICL-IUI
Lslagialll
T-Ti

09-04

1-10
1 1U

Z-l

integrated circuit vocation

Z-U 1 OD

Z-l j

2-2

Integrated Circuit Pin Location - Top View

12-0134

2-13

3-1

Ground Reference

3-2

MEM START and STROBE

3-4

3-3

Positive Memory Current

3-5

3-4

Negative Memory Current

3-5

Teletype Clock (Sweep at .5 ms)

3-9

3-6

LTT TP0/TP2 Pulse Duration
LTT TP3/TP4 Pulse Duration

3-10

3-7

3-11

ILLUSTRATIONS (Cont)
Figure rNO.

ATI INO.

Page

3-11

LTD XTLK Delay Time
LTD TTOK Delay
LTD Tape Fail Delay
LTD ACIP Delay

3-12

Mark Clock

3-17

3-13

3-18

3-15

TU55 Brake Adjustment
TU55 Torque Adjustment Tabs
TU55 Stop Delay Adjustment

3-16

3-17

3-18

80 ms Brake Delay Adjustment

3-19

3-20

25 ms Oscillator Adjustment
D/A Line Display

3-21

Sample and Hold Adjustments

3-22

A-to-D Display

4-1

PDP-1 2 Equipment Layout

4-2

4-8

TU55 LINCtape Transport
VR12
TU55 and VR12 Mounting Assembly
TU56 LINCtape Transport
Front Assembly of TU56
Rear Plate Assembly of TU56
Top View of TU56 Rest Plate Assembly

5-1

Teletype Connections

12-0088

5-4

5-2

Teletype Signal Waveform and Bit Relationship

81-0010

5-5

3-8
3-9

3-10

3-14

4-3

4-4
4-5

4-6
4-7

12-0261

3-12
3-13
3-15

3-16

3-20
3-21

Skew Checker Schematic Diagram

12-0127

3-23

Skew Checker Output

12-0126

3-24
3-25

3-26

12-0086

3-27

3-28
3-31

12-0260

4-7

4-9
4-9

12-0253

4-10
4-11

12-0258

4-12

12-0257

4-12

12-0254

4-13

for the Character "U"

TABLES
Title

1 oUlC I^IU.

Page

1-1

Standard PDP-1 2 Shipping Specifications

1-2

Hubbell Wall Receptacle Part Numbers

1-10

1-3

Power Cable Line Identification

1-11

2-1

Maintenance Equipment

2-1

2-2

Power Supply Specifications

2-5

3-1

Memory Diagnostics

3-8

3-2

Monitor Table for Channels 20 through 37

3-34

4-1

Prewired Options

4-1

4-2

Option MAINDECs Checklist

4-2

4-3

Option Module and Cable List

4-3

4-4

Interconnections of TU55

4-10

4-5

DC Voltage Connections

4-14

4-6

TU56 Logic Cable Connections

4-14

vii

1-9

TABLES (Cont)
Table No.

Page

Title

Format Conversion Table

4-15

4- 8

VR 12 Controls

4-17

5- 1

Teletype Maintenance Tools

5-1

5-2

Maintenance Programs

5-2

4-7

5-3

Spare Parts for Keyboard Model 33 ASR Teletype

5-6

D-l

Options Diagnostics

D-4

viii

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 I/O 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 designed 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 application.
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:
a.

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

10-047B

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-1 2 Systems can be ordered under three types of layout plans. The three types are:
Plan A - din unmodified, standard PDP-1 2 System, or the PDP-1 2/10, /20, /30, /40 series. This plan
provides a standard configuration, including standard cable lengths to free-standing peripherals

(shown in System Drawings PDP1 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;

C- a special PDP-1 2 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 layout of PDP-1

Plan

cabinet and peripheral equipment locations, and submit the layout to DEC for approval. If the

PDP-1 2 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-1 2 layout:
a.

Easy observation of I/O 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 system 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.

1.1.5 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. Compliance with industry-acceptable and local
regulations are the responsibility of the system user.
a.

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.
b.

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.
c.

If an automatic carbon-dioxide fire protection system is used, an alarm should sound on

release of the
d.

C0 2 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, loss 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 1 10°F (43°C), at a relative humidity of 20 to 90 percent with no condensation. However, typical sys-

tem 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.
b.

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.
Drawing Number

System
a.

PDP-1 2C Basic System

PDP1 2-0-1 Sheet 2 of 4

PDP- 1 2B Intermediate System

PDP 2-0-

PDP-1 2A LINC System

PDP1 2-0-1 Sheet 1 of 4

Sheet 1 of 4

NOTE
The PDP-12/10, /20, /30, /40 configurations are listed below.
PDP- 12/ 10 Basic Laboratory Instrument System
PDP-12 Dual Instruction set Central Processor
4096 12-bit, 1.6 ms Core Memory
Direct Memory Access Channel

6 Sense Switches

Hardware Signed Multiply Instruction (9 jus)
1 5 Auto-Index Registers
1

2 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-1 2/10 plus:

TCI 2

TU56
VC14
VR14
API-1 2 Multiple level automatic priority interrupt

(continued on next page)

1-5

PDP-12 Advanced LINC
Includes all of the features of PDP-1 2/20 plus:

MCI 2 4K memory extension
KW12-A Real Time Clock
PDP-12 Super LINC
Includes all of the features of PDP-1 2/30 plus:

FPP-12 Floating Point Processor

System Expansion

1.2.2

As shown in the drawing referenced on Page 1-5 (Sheets 1 through 4), a PDP-12 System can be expanded by
addition of the options which are housed in H961-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 PDP1 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-12 System.

1.2.3 I/O Interface

A complete discussion of the interface requirements of the PDP-1 2 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.

Preliminary Procedures

1.3.1

Prior to receiving the equipment, the customer should:
a.

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-1 2 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.
is ordered.

If a problem is noted,

DEC must be informed at the time the equipment

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

DEC TAPE
STORAGE
RACK
#1809544
OR BLANK
PANEL

BAY C

TU55
DS32

RF08

TU55

TU55 /56

2. MM8I
3. AF01

TU55/56

BAY B

DEC TAPE

STORAGE
RACK

TU55/56

TU55 /56

2. MM8I

OR BLANK

2. DS32

RS08

PANEL
K W 12
PANEL OR
BLANK
PANEL

TU55

MM8I

TU55
DS32

PC12
1

DF32

VR12

72
AD12 PANEL

PDP-12

CONSOLE

TABLE

RS08

2. BAI2
.

MM8I

2. PCI 2

FAN

PT08

DR12

BLANK

PANEL
724
P/S

BA12

AG12

PANEL OR
BLANK

BLANK

DM01

DW08-A

FLOOR LINE

NOTE:
All

dimensions in inches

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

EXPANDER

ADDITIONAL

CABINET

H961-C

CABINETS

H961-C

TELEPRINTER
PAPER SUPPLY
CONTAINER

H
I

KSR-35

ASR-35

I
«

40-

NOTE:
All

dimensions are in inches

Figure 1-4

Minimum PDP-12 Equipment Floor Plan Requirements
(See Volume III, Drawing PDP1 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

PLASTIC

AND SHIPPED IN HEAVY
CARDBOARD OR 1/2-in. PLYWOOD
CONTAINER

COMPUTER

WOOD AND CARDBOARD CORNER
PACKING WITH METAL STRAPPING
TO PALLET

78-in.
•oerrAt equipment corpqraticjn

MAYNABD,. MASSACHUSETTS

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

MAXIMUM gross shipping weight
1300 lbs. (crated) (PDP-12 A 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-1 2 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 Ex-

pander 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 packing and shipping practices. If the user's constraints dictate, other ship-

ping 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-1'2 Shipping Specifications

Dimensions

PDP-12

C,/10

Weight
Height

Width

Depth

78 in.

45 in.

42 in.

Storage Temperature

600 lb*

40° to 110°F
(5° to

45°C)

B, /20

78 in.

45 in.

42 in.

900 lb*

40° to 110°F

A, /30

78 in.

45 in.

42 in.

1000 lb*

40° to 110° F

/40, LDP

78 in.

45 in.

64 in.

1600 lb*

40° to 110°F

2 H961-C Expander Cabinets

78 in.

45 in.

82 in.

1800 lb*

40° to 110°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 con-

nector 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 17.5 A at 1 15 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-1 2 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 receptacles
(or equivalent) to be compatible with the PDP-1 2 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

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

333 1-G (3331 may be used)

Receptacle 7310-G (7310 may be used)

Cap

332 1-G (3321 may be used)

SERVICE OUTLET
120V 6OH2 SINGLE PHASE
15A/U GND

NEUTRAL

FRAME GROUND
CAUTION
When neutral Is not available for the
above service, a receptacle of the
above design shall be used, but both
parallel slots shall be short to prevent
polar/zed parallel blade plugs (caps)

from fitting.

FRAME GROUND

NEUTRAL OR
LINE 2
LINE 1

RECEPTACLE No. 3330-G
CAP No. 333t-G
1

5V 60Hz SINGLE PHASE
30A TWIST-LOCK

FRAME GROUND

NEUTRAL OR
LINE 2

RECEPTACLE No. 7310-G
CAP No.3321-6
230V 50Hz SINGLE PHASE
20A TWIST- LOCK

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-1 2 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 CB1 (see Drawing D-CS-724-0-1 Volume III).
,

Table 1-3

Power Cable Line Identification
Pigtail Information

Terminal Strip Nomenclature
Wire Color

Line

Green

Frame Ground

White

Neutral/Line 2

Neutral or Line 2

Black

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 120 Vac ±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
1

Procedure

Remove the outer shipping container.

NOTE
The container may be either heavy corrugated
cardboard or 1/2-in. plywood. In either case, re-

move 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.
2

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-1 2 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-1 2 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:

Procedure

Step
1

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 .4.5

Teletype Unpacking
Step
1

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.

stand.

Remove the Teletype console from the pallet, and mount it on the
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 1375 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-1 2 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-1 2 Cabinet to ensure that sufficient strain relief is provided regardless
.

of Teletype position.
3

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 DEC-

supplied cable and connector have been made.
3

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 mag-

netic 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 Operating Checks

CB1 applies ac
power to the power supply only, and may be left on continuously. Prior to applying power, measure each power
Set the main circuit breaker CB1, located on the rear of the 724 Power Supply chassis, to ON.

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

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.
original printed sequence should appear on the paper.

As the tape is read, a duplicate of the

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 FILL 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.
3

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.
,

/\aaress ^ivi/\j

iiio iruc

6032

7756
7757
7760
7761
7762
7763
7764
7765
7766
1161
7770

6031

5357
6036
7106
7006
7510
5357
7006
6031

5367
6034
7420
3776
3376
5356

7771

7772
7773
7774
7775

1.5.5

nun ^rvig

Running MAINDECs

The set of MAINDEC diagnostic programs is used to check out the operations of each section of the PDP-1
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

MODE switch to 8 MODE.

Set the

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.

4
5

Set the reader switch to START.
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.
7

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:

1-17

Step

Procedure

Set the LEFT SWITCHES to 7777.

Set the

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

MODE switch to 8 MODE.

trailer code is sensed.

After the tape stops, examine the Accumulator indicator lights. They should
If they are not, try reloading the tape. (The state of the LINK

all be off.

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 explain-

ing 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

Introduction

Section 2

Equipment

Section 3

Preventive Maintenance

Section 4

Corrective Maintenance

Section 5

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, inter-

active hardware and software and modes of operation (8-Mode and LINC-Mode) demand that a systematic main-

A systematic preventive

tenance program be initiated upon installation and faithfully followed thereafter.

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 endorsement.

Table 2-1

Maintenance Equipment

Equipment
Multimeter
Oscilloscope

Model or Type

Specification

10K ohms/V - 20K ohms/V

Triplett Model 310

DC to 50 mc with calibrated de-

Tektronix Type 453

flection factors from 5
1

OV/div.

mV to

Maximum horizontal

sweep rate of 0.1 jus/div. Delaying sweep is desirable and dual
trace is a necessity.

"(continued on next page)

2-1

Table 2-1 (Cont)

Maintenance Equipment

Equipment

Model or Type

Specification

Probes

XI 0 with response characteristics
matched to oscilloscope

Clip-on Current Probe

m A, mV or

0 mA, mV

Tektronix Type P6010

Tektronix Type P6019 with
nn<i<iivp
^ClOOJ.Vt' tprminpitnr
tt/i 11 unci IU1

Recessed Probe Tip

Tektronix

(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-20557-1

30-Gauge Bit for Wrap

Gardner-Denver 504221

Tool
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 termi-point
connectors

Screwdriver

6-in. non-conductive shaft

DEC Type 142

Field Service Kit

Precision Voltage Source

-lVto+lV0.1%

Electronic Development Co.

PDP-1 2 DIAL Maintenance
LINCtape, Assorted Writeups and Back-up Paper
Tapes*
*Supplied with the PDP-1 2A, PDP-1 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-1 2, 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.

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.
this additional testing.

The reliability test programs provide

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 magni-

tudes 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.
selecting error handling is defined in the

2.2.2

The use of the data switches for

MAINDEC write-ups provided with the software package.

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.
3

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

MODE switch to LINC; depress I/O PRESET.

Set

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-1 2 must receive certain routine maintenance attention to ensure maximum life and reliability to the computer system.

DEC suggests a schedule of 000 hours for electrical inspection, and 500 hours (or every month)
1

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
1

Procedure
Clean the exterior and interior of the computer cabinet, using a vacuum cleaner

and/or clean cloths moistened in nonflammable solvent.
2

Clean 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. 1 501.

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.
8

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.

1 1

Perform all preventive maintenance operations for each peripheral device
included in the PDP-1 2 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
Current

Use

15V (rms)±20%

Panel Lights

+5V, ± 5%

20A

Voltage

Logic

- 11 J
+ 10%
5 V —
1 \J /V

Sense Amplifier

Main Supply

-15V ± 10%

Sense Amplifier Slice

Reader Clock

-30V ± 10%

Memory Supply, (-)
Teletype

+10V±20%

2.4

R-Series Modules

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 en-

vironment 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-1 2. 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

2-5

2.4.1

Preliminary Investigation

Before beginning troubleshooting procedures, explore every possible source of information. Gather all available

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 distinguish-

ing 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.
cannot be started, refer to Section 2.5.2.

If the machine

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.

problem indicates a logic failure.

Generally, a recurring

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,

being used properly? Are memory fields being used properly?
i.e.,

Is the program

NO PAUSE, etc.,

making unwarranted assumptions;

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.
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

The procedure

2.5.2 Console Checks

Assuming a cold start, check the following console functions.

If any malfunctions occur, repair the problem before

continuing with the procedure.

Procedure

Step
1

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)?
,

I/O 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?
4

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 I/O 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

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 Is); repeat Steps 8 and 9.

1 1

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 KP12 Power Fail Option is installed and switched ON.

2-7

Procedure

Step
15

Depress START 400.
a.

Does the MA = 0400?

Does the PC = 0401?

Does the MB = 0000?

Does the IR = 0000?

Reset STOP; depress CONT.
a.

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).
18

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.
a.

Does the RUN light illuminate?

Do the MA and PC cycle through 1 K of memory? (4000-5777)

Does the AC remain cleared?

Depress SING STEP.

Does the computer stop?
22

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 1 K of memory at a rate determined by

AUTO RESTART DELAY, COARSE and FINE adjustments?
24

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.

2.5.3

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.

2-8

If the LINCtape portion of

the computer is inoperative and the tapes cannot be read in any manner, refer to Paragraph 2.5.5, TCI 2 Tape

Subprocessor. Other methods of reading tape include reading entire tests manually, or reading single blocks.

necessary, read a block using the RDE instruction, thereby bypassing the checksum logic.

A confidence check of module and timing stability can be made by using MAINDEC-1 2-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 turn, 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 1 A, 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-12 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 (TCI 2-0-10).

Watch the tape movement and direction.

Is it in accordance with the tape state indicators on the console?

Re-

view 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-1 2-D3 AD, 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
4021/1000
4022/1020
4023/0001
4024/1140
4025/0021
4026/1460
4027/7777
4030/6020
4031/1020
4032/1000
4032/1021
4034/6020

RDC

/READ AND CHECK

1000

/QN & BLOCK NUMBER

LDAI
/INCR BN

0001

ADM
/INITIALIZE LOC21
/WHEN IT REACHES 7777

SAEI
7777

JMP 20

LDAI
1000

STCI 1
JMP 24

/RESTART

This routine reads contiguous blocks from 0 to 777, thus allowing time to check timing and data transfers before

turnaround.

2.5.6

TC12 Console Checks
Step
1

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.
a.

0701 (TAPE IR = 001)

0702 (TAPE IR = 010)

0703 (TAPE IR = 011)

0704 (TAPE IR = 100)

0705 (TAPE IR = 101)

0706 (TAPE IR = 110)
g-

0707 (TAPE IR = 111)

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

(continued on next page)

2-10

Procedure
Depress DO.
a.

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).
c.

While in the SEARCH mode, does the MB = 0777? (This is the block

number from the RIGHT SWITCHES.) Does the IR = 0700?
d.

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

BLOCK mode?
e.

At the completion of the instruction, does the MA = 4377, indicating
correct address transfer and memory incrementation?
Does the IR clear to 0s? (MB will equal data transferred from tape to
Does the TAPE INST = 000?

location 4377.)
g.

Does the AC = 7777 at the completion of the tape instruction?
AC ¥= 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 1 1
Set 0701 into the LEFT SWITCHES, set 7000 into the RIGHT SWITCHES,

and depress DO.
a.

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.
c.

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 0s?

Fill memory with 7777 and repeat Steps 10, \0a., and 10Z>.
Memory should still be all 0s. 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-1 2-D3DA-PB, TAPE EXERCISER, to confirm LINCtape

control reliability.

2.5.7 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 dc 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.
2.5.8

Module (Circuit) Troubleshooting

Engineering schematic diagrams of each module are supplied with the PDP-12 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 XI 0 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 10 to L)

If readings 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 100 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 direc-

tions, consider a transistor as two diodes connected back to

back. In this analogy, PNP transistors would have cathodes con-

nected 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 re-

sistance 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
E4

under dynamic conditions and using a module extender to

make terminals readily accessible. Using PDP-12 engineering
drawings (Volume III) and the M-series module schematics

(Volume IV), an integrated circuit is located on a circuit
board in the following manner:
Figure 2-1

Integrated 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

n n n n n n n

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.

u u u u u u u
1

2.5.9 Repairs and Replacements

7
I2-0I34

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

Figure 2-2 Integrated Circuit

office for subsequent repair and/or replacement. If,
however, for expediency, field repairs must be per-

formed, it is imperative to take the following precautions.

2-13

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:

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 com-

ponent 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.

2.5.1 1

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
1

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

Adjust the oscilloscope as follows:

Channel 1 only

Trigger:

Mode: Channel 1

Channel 1

5V/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 trimpot (if there are two) on module G826, locations E2 and F2, for approximately -12V.

Turning the trimpot counterclockwise increases the voltage (refer to Paragraph 3.2.1).

3-1

CHAPTER 3

ADJUSTMENTS

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

address tests and
Testing and adjusting of the PDP-12 memory section are accomplished by running the memory
memory for
the
tune
to
necessary
be
may
currents
read/write
memory checkerboard tests. Adjustment of the

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
1

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

Adjust the oscilloscope as follows:

Channel 1 only

Trigger:

Mode: Channel 1

Channel 1: 5V/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 trimpot (if there are two) on module G826, locations E2 and F2,
Turning the trimpot counterclockwise increases the voltage (refer to Paragraph 3.2.1).

3-1

for approximately -1 2V.

Figure 3-1

Ground Reference

3.1.2 Initial Strobe Adjustment

Step

Procedure

Turn off the computer and remove power.
2

Remove module M360 at location E14 (MCT) and turn the potentiometer
fully CCW.

Turn the potentiometer CW five full turns.

Return the module to location El 4.

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 \e. until the program is loaded.

(continued on next page)

3-2

Procedure

Step
1

RIM LOADER

(cont)

Address

Instruction

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

/6032

/CLEAR AC & KBD FLAG

/6031

KCC
KSF

15351

JMP. 1

/6036

KRB

/7106
/7006

CLL RTL
RTL

/7510

SPA
JMP. -6

15351

/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)

/6031

RTL
KSF

/5361

JMP. -1

/6034

KRS

/NOT UP; WAIT
/READER BUF^AC
/IS THIS AN ADDRESS WORD?
/NO, USE INDIRECT
/YES, SET UP ADDRESS
/JUMP BACK

11006

/SKIP ON KBD FLAG

/7420

SNL

13116
13316

DCAI +3
DCA +2

/5356

JMP

-17

Set 7756 in the LEFT SWITCHES.

Set 0000 in the RIGHT SWITCHES.

Insert the basic

CHECKERBOARD LOW in the Teletype reader

(M AIN DEC-08-D 1 L 1 )
5

Turn the Teletype ON LINE.

Set the reader to START.

Set the

Depress the I/O PRESET.

Depress the START LS.

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

1 1

Set 0005 in the LEFT SWITCHES.

Set 0 1 0 1 in the RIGHT SWITCHES.

Depress I/O PRESET; then START LS.

Set the oscilloscope as follows:

MODE switch to 8 MODE.

Channel 1 only

Trigger:

Mode:

Sweep: 0.1 ms

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

On the scope, set the Channel 1 GND reference 1 cm above the

ALT

center graticule.
f.

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 B 1 6 J 1 (CPTP START MEMORY H).

Attach the Channel 1 scope probe to E14S2 (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.

'WWFigure 3-2

MEM START and STROBE

3.1.4 Final Current Adjustments

Step
1

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:
Channel 1 only

Trigger:

Mode: Channel 2 only

Channel 1

Channel 2: 50 mV/cm

Channel 2 GND reference: 2 cm below center graticule (see

2V/cm

Figure 3-1)

Current probe terminator to 2 mA/mV

Sweep: 2 /is

Slope: Positive; Source: Internal

Attach the current probe to Channel 2.

Attach the Channel 1 scope probe to B16J1 (CPTP START MEMORY H).
(continued on next page)

3-4

Procedure

Attach the current probe to the loop provided from C1K1 to C7T2, with the

arrow toward C7T2.
Adjust rightmost trimpot R28 on module G826 (locations E2 and F2) until
+5%, as shown in Figure 3-3. (Turning the
the positive waveform is 320

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%..

;/vH" " ""I

Figure 3-3 Positive Memory Current

Figure 3-4 Negative Memory Current

3.1.5

Memory Margins and Final Strobe Adjustments
Step
1

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 + 1/2 (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
If current is incorrect, bits

may be picked up or lost. If STROBE is not correctly adjusted, whole words may be

Reading may also produce all MB bits set when they should be cleared.

lost.

3.2

MEM START.

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.
3.2.1

Check Procedure

If the E02J2 output is +3V, the regulator control has detected a power failure on the +5 or -15V bus.

Check the

+5 and -15 V power supplies; if the outputs are within specification (see 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 an oscilloscope or meter at E02J2 (POWER OK H), turn the potentiometer CCW until the signal
goes high (+3 V) (MCT). Then slowly turn the potentiometer clockwise until the signal just goes low; continue a

few degrees (approximately one hour on a 1 2-hour dial) more for the single-turn revision H modules, or 1 /2 turn
more for the 1 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 potentiometer.

3-6

POWER OK becomes high, symptoms may include loss of the instruction and data fields, 0

0 -» RUN flip-flop, 1

3.3

contents of AC,

8 Mode and 1 -+ FETCH (i.e., I/O PRESET).

EXTENDED MEMORY MC12

If the

MCI 2 Memory Extension Control (alone, or with the MM8I-A and/or MM8I-B options) is included in the

user's system, the following procedure should be performed as a part of the memory current and strobe adjust-

ments.

3.3.1

Set-up and Adjustment Procedure

Step
1

Procedure

Repeat Steps 1 through 1 3 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:

CHANGE DATA FIELD TO 0
TAD INDIRECT LOC 0070
CHANGE DATA FIELD TO
DCA INDIRECT LOC 0070
INCREMENT LOC 0070

7700/620 1
7701/1670
7702/62 1 1
7703/3670
7704/2270
7705/5300
7706/7402
7670/0000

JMP

-5

HALT TRANSFER COMPLETE

Set 0005 in the RIGHT SWITCHES.

Set 0 1 0 1 in the LEFT SWITCHES.

Set 1 in the INST FIELD.

Depress the START LEFT SWITCHES.

Connect the Channel 2 probe of the scope to E15S2 (MCT STROBE FIELD 1 H).

NOTE
Do not depress the I/O PRESET.
The adjustment procedure is identical to Initial Current Adjustments and Final Current Adjustment Procedure
(Paragraphs 3.1.1 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

MAINDEC

Program

Function

CBH

DEC-08-D1L2-PM

Tests Stack 0 for noise at low end

CBL

DEC-08-D1L1-PM

Tests Stack 0 for noise at high end

ADDRSHI

DEC-08-D1 BZ-PM

Tests Stack 0 low end addressing

ADDRSLO

DEC-08-D1R1-PM

Tests Stack 0 high end addressing

MEMDATA

DEC-12-D1EA-PB

Test Stacks 0+1 for random data
(see Writeup DEC-12-D1EA-D)

EXT CB

DEC-08-D1DA-PB

Tests Stacks 0+1 for noise

EXT AT

DEC-08-D1HA-PB

Tests Stacks 0+1 for addressing

JMPSELF

DEC-12-D1BA-PB

Tests Stacks 0+ 1 for address select speed

NOTE
PB — Paper- tape Binary

PM - Paper-tape RIM
D — Document

3.4

TELETYPE CLOCK
Procedure

Step
1

Oscilloscope set-up:

Normal

Trigger:

Mode: Channel 2 only

Sweep:

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

Channel 2 GND reference: 2 cm below center graticule

Channel 2: 2V/cm

1.0 ms

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

Connect the Channel 2 scope probe to N8K2 (TTO 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 5.

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.

Step
1

Procedure

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

Procedure
(cont)

Repeat Steps Id. and \e. until the program is loaded.

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

0000/7300
0001/7404
0002/6151
0003/5000

Set 0000 in the LEFT SWITCHES.

Set 0040 in the RIGHT SWITCHES (simulates LTT TP0).
Set the

MODE switch to 8 MODE, I/O PRESET.

Depress START LS (LEFT SWITCHES).
Set up the oscilloscope as follows:

Channel 1 only

Trigger:

Mode: Alternate

Slope: Negative; Source: Internal

Sweep: 0.5 ms

Channels 1 and 2: 2V/cm

Connect the Channel 1 scope probe to C18M1 (LTT TP0 L) and the
Channel 2 scope probe to C20N1 (LTT TP2 L).

As shown in Figure 3-6, LTT TP0 should be a negative pulse, approximately
100 ns duration. LTT TP2 L should be a negative pulse, approximately
1

/xs in duration (LTT).

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

Connect the Channel 1 scope probe to C18N1 (LTT TP3 L) and the Channel 2
scope probe to (LTT TP4 L) on C19N1
Set the scope sweep to 0. 1 jus.

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 TP0/TP2 Pulse Duration

3-10

Figure 3-7

3.5.2

LTT TP3/TP4 Pulse Duration

LTD XTLK Delay

The Cross Talk (XTLK) delay (LTD), when initialized, ensures that there will be only one TTO or TT1 for a given
zero crossover on the tape (during read and write).

XTLK is the most important TCI 2 adjustment and must be

correct.

Procedure

Step
1

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

Depress I/O PRESET and START LS switches.

Set up the oscilloscope as follows:

MODE switch.

Channel 1 only

Trigger:

Mode: Alternate

Slope: Negative; Source: Internal

Sweep:

Channel 1 GND reference at the center graticule

Channel 2 GND reference 3 cm below the center graticule

jus

Connect the Channel 1 scope probe to C28U1 (LTT TPO L) and the Channel 2
scope probe to C28H2 (LTD XTLK H).

Adjust the right potentiometer of M307 (location C28) for 9 us (LTD). Turning the potentiometer CCW increases the delay time, as shown in Figure 3-8.

0#rs£^

W ^£

*fi**P

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

-9/xs-

Figure 3-8

3.5.3

LTD XTLK Delay Time

LTDTTOK 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 ms 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 intermittent, the TTOK delay may

be suspected.

Procedure

Step

Halt the computer; turn off power.

Remove W603, at location F 16.

Restore power.

Load the program as directed in Paragraph 3.5.1.

Set 0000 in the LEFT SWITCHES.

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

Set the

AUTO RESTART delay as follows:

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.

1 1

Set the oscilloscope as follows:

Channel 1 only

Trigger:

Mode: Channel 2 only
(continued on next page)

3-12

Procedure

Step
1 1

(cont)

Slope Negative Source Internal

Sweep: 5 jus

Channel 2 GND reference 1 cm below the center graticule

Sweep Mode: Normal

;

Connect the Channel 1 scope probe to C28U1 (LTT TPO L) and the Channel 2
scope probe to C28E2 (LTD TTOK L).

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

Adjust the left potentiometer of M307 (location C28) for 48 jus. Turning

the potentiometer CCW increases the delay.
1 5

Refer to Figure 3-9.

Halt the computer, remove power.

Reinstall the W603, at location F16.

Figure 3-9

LTD TTOK Delay

LTD TAPE FAIL Delay

3.5.4

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 CI 7.

•

Restore power to the computer.

(continued on next page)

3-13

Step

Procedure

Load the program as directed in Paragraph 3.5.1

Set 0000 in the LEFT SWITCHES.

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

Set the

AUTO RESTART delay as follows:

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:

1 1

Channel 1 only

Trigger:

Mode: Channel 2 only

Sweep: 50 ms

Slope: Negative; Source: Internal

Set Channel 2 reference

Set Channels 1 and 2 to 2V/cm

Sweep Mode: Normal

GND to center graticule

Connect Channel 1 scope probe to C30U1 (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 increase the FINE AUTO RESTART delay until the trace is stable.
Increasing the

AUTO RESTART delay past 300 ms inhibits the delay. Ad-

just the right potentiometer of the M307 Module, at C30, for 300 ms.

Turning the potentiometer CCW increases the delay.
15

Refer to Figure 3-10.

Halt the computer; remove power.

Reinstall the M304 Module at location CI 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 3-1 0

LTD Tape Fail Delay

Procedure

Step
1

Load the following program:

CLEAR AC & LINK
TAD K20 AC = 0020

0000/7300
000 1 / 1 006
0002/61 52
0003/7006
0004/61 52

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

0005/5000
0006/0020

K20

Set 0000 in RIGHT SWITCHES.

Set the

AUTO RESTART delay as follows:

Set the COARSE selector to 2.

Set the FINE control to SLOW.

MODE switch to 8 MODE and depress I/O PRESET.

Set the SING STEP,

Depress START LS; depress and hold AUTO key.

Depress CONT; then release AUTO.

Set the oscilloscope as follows:

Channel 1 only

Trigger:

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-G3/E2 (LTD ACIP L).

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

Refer to Figure 3-11.

Figure 3-1 1

3.5.6

CCW decreases the delay.

LTD ACIP Delay

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

jtxs

± 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

shorter than 7.5 /-is, data will not transfer to virgin tape correctly, i.e., running

a PIP copy program.

CAUTION
Remove all tapes before starting this adjustment.
Step

Procedure

Halt the computer. Turn off the power.

Install a jumper from E21K2 to E21T1.

Turn on the computer.

Set up the oscilloscope as follows:

Channel 1 only

Trigger:

Mode: Channel 1 only

Sweep:

ijls

(continued on next page)

3-16

Procedure

Step

4 (cont)

Slope: Positive; Source: Internal

Channel 1

GND reference of Channel

2V/cm
1

at the center graticule

Connect Channel 1 scope probe to E21D2.
Adjust the M401 Module at location E21 for 7.5 lis as shown in Figure 3-1 2.

Turning the potentiometer CCW increases the clock frequency.
7

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

Figure 3-12

Mark Clock

NOTE
The diagnostics TCI 2-1 and TC 12-11 should be used as a final
test on the TCI 2 LINCtape Control.

3.6

TU55 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 TU55 tape transports; other PDP-12
systems employ the TU56 transport. Users are directed to the
TU55 or TU56 Maintenance Manuals for complete mainten-

ance 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
quickly. Correct
are relatively high torque and low inertia, which allows the tape to be started and stopped
lifted off the
operation of the tape system requires the tape to be rapidly started and stopped, without its being
the most
heads. Tape lifting can be a frequent source of problems for the LINCtape system, and also one of

difficult to discern.

3-17

The following mechanical adjustment procedures (Paragraphs 3.6.1 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

TU55 Brake Adjustment
Step
1

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 1 15-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

Figure 3-13

BRAKE SHOE

TU55 Brake Adjustment

(continued on next page)

3-18

Procedure

Step

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.
6

After the adjustment is made and the Allen setscrews are 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.

properly adjusted brake should produce a minimum of "clicking."

3.6.2

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

Reinstall 1 15-Vac line cord.

TU55 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
Procedure

Step
1

Line voltage (ac) to TU55 on.

Scratch tape installed on both hubs.

Brake gap set as described in Paragraph 3.6.1

Switch the unit to LOCAL.

Connect the VOM to the tab terminals of Module G850 at location Al 2
(right motor) as shown in Figure 3-14. Expect a reading of approximately
60 Vac.

Depress FWD

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

Connect the VOM to the terminals of Module G850 in location Al 1 (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.

switch and release.

3-19

Trailing Torque Adjustments

Step
1

Procedure

Connect the VOM to tab terminals of the G850 Module in location A12
(right motor).

2
3

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 G8 50 Module handle.

Make certain

that the tape is still in motion while the adjustment is made. Adjust for 85 Vac.
5

Connect the VOM to the tabs of the G850 Module in location Al 1 (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).

during the adjustment.

3-20

Make certain that the tape is still in motion

FRONT OF TAPE TRANSPORT

R303 MODULE TRIMPOT R9
DELAY ADJUST
TU55 Stop Delay Adjustment

Figure 3-15

Stop Delay Adjustment
Procedure

Step
1

Switch the tape unit to LOCAL.

Set the oscilloscope as follows:
Trigger:

Mode: Channel 1

Channel 1

Sweep

2V/cm

10 ms

Connect the scope probe to A04D.

Depress and release FWD

3.6.3

Channel 1

switch.

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

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 1 /8 in. above the
guide edges.

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

Head Removal
Step

Procedure

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 G851 Relay Board.

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

Remove the tape head from the transport.

Head Installation
Step

Procedure

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 1 /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
Step

Procedure

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

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

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 TU55 wiring. In some transports,

however, the +10V lead may be read; in this case, this
will be a green wire connection to the checker.
c.

Connect the oscilloscope probe to the point marked SKEW.
Connect the scope ground to the point marked GND (black).
Adjust the scope for a l-jus/cm horizontal sweep and a lV/cm
vertical sensitivity.

(continued on next

3-22

Figure 3-16

Skew Checker Schematic Diagram

Procedure

Step
2 (cont)

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 jus.
(Refer to Figure 3-17).
e.

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 lis. If a large amount of
skew is present, shimming of the tape head becomes
necessary.

Shim the Tape Head
a.

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

\ \

4-ht-h

Mill!

1
1

NOTE A RAGGED TRAILING 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 re-

check the skew. The skew must be less than 3 /us in both
directions..

3.7

TU56 TAPE TRANSPORT

Complete service and adjustment and other maintenance information can be found in the TU5 6 Maintenance

Manual DEC-OO-HRTA-D. For convenience of maintenance personnel, the TU56 Brake and Oscillator Adjustments are provided below:

3.7.1

TU56 Brake Adjustment
Procedure

Step
1

Mount a scratch tape on the transport.

Tilt the tape transport front panel forward.

Set the oscilloscope as follows:

Normal

Trigger:

Mode: Channel 1

Sweep:

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

10 ms

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

Set Channel 1 to 2V/cm

(continued on next page)
3-24

Step

Procedure

Connect the Channel 1 scope probe to B08F2. (See drawing
D-BS-TU56-0-TLD).

Enter the following routine:

MTB

4020/0703
4021/0300
4020/6020

Block 300

JMP .-2

I/O PRESET

START 20
Unit Set to UNIT 0

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 ad-

justment procedure without repeatedly advancing and rewinding the tape

hubs manually.
6

To adjust the left hub brake delay, turn the upper potentiometer for a delay
of 80 ms (see Figure 3-1 8).

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 80 ms Brake Delay Adjustment

3-25

3.7.2 Oscillator Adjustment

Procedure

Step
1

Set the oscilloscope as follows:

Normal

Trigger:

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 (VK12, VC12)

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 VR12 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 VR1 2 display

system is available in the VR12 Point Plot Display Maintenance Manual (DEC-CR-H6AA-D).

3-26

3.8.1

Digital-to-Analog Adjustment Procedure (A615)

Step
1

Procedure

Load the following program:
4020/0 1 62

4021/6020

DISPLAY A POINT & INCREMENT
JMP -1 & REPEAT
.

Set the RIGHT and LEFT SWITCHES to 0.

Set the

Turn on the VR12 and set the brightness potentiometer approximately 3/4

MODE switch to LINC; depress the I/O PRESET; depress ST 20.

of a turn from off.

CHANNEL SELECT to

and 2.

Set the

Depress START 20.

A straight line will be displayed. If the line is of uniform brightness and con-

tinues 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

D, 2 SEGMENT

E, OPTIMUM

DISPLAY

Figure 3-20

D/A Line Display

The four most significant bits of Module A615, 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 signifi-

cant 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

R37

Figure 3-21

R38

R39

R40

Sample and Hold Adjustments

Procedure

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

justing toward the most significant bit, bit 3.

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 A61 5 at locations E and F37, halt the computer and
turn off the power. Swap Module A61 5 in locations E and F37 with the
Module A615 in locations E and F36. Repeat the entire A615 Adjustment

Procedure.

3-28

3.8.2

VR12 Size and Position Adjustments
Procedure

Step

Size can be adjusted to the user's requirements by adjusting the X- and Y-

Position potentiometers.

On Module M7

1 1

(locations C and D37), set the three switches for normal

operation as listed below:
a.

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
1

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

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

Set 070 1 in the LEFT SWITCHES (RCG).

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

Set

Depress DO key; when tape motion stops, depress I/O PRESET; then

MODE switch to LINC; depress I/O PRESET.

START 20. (At this point, a

should be displayed at the left of the

screen. Directly across from it, a bar (-) will also be displayed.
this does not occur, check to be sure that

CHANNEL

is selected

and

the BRIGHTNESS potentiometer is fully CW.)
7

On the Teletype, type LINE FEED (an arrow will appear at the bottom
left of the screen).

> LO DISPTST, > 0).

Type LO (space) DISPTST; then 0 (Example:

Type a carriage return.

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

1 1

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 (M AINDEC- 1 2-D6B A-D)

CHANNEL SELECT control to

and 2.

Set the

Set the BRIGHTNESS control fully CW.

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

Slowly slide the VR1 2 video display unit forward until it stops. (The
BRIGHTNESS PRESET adjustment is located on the top of the VR12.)
(continued on next page)

3-29

Step
6

Procedure
Adjust the BRIGHTNESS PRESET control for the highest brightness level
level possible that does not cause blooming of the presentation.

CAUTION
Excessive 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
1

2
3

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 G912 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
1

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 070 1 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 I/O 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,0 then RETURN. The A/D TEST
is

a self-starting program.

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

(continued on Page 3-32)

3-30

3-31

Step
1 1

Procedure

Note the starting position of knob 00. Turn the potentiometer slowly CCW,
monitoring Channel 00 on the screen until it reads +776
The change must
g
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 10 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
1

Procedure

Load the A/D TEST as specified in Steps 1 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 turn off the power.
3

Remove Module A2 1 4 at location E33

Install a jumper from

Turn on the computer and depress the I/O PRESET.

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

D32R2 to D32F2.

While monitoring Channel 17, adjust the COARSE AD J (see Figure 3-21)

Module A404 (locations E and F34) until Channel 1 7 displays 000 (see
Figure 3-2 1 ). Then adjust the FINE ADJ until the sign of the Channel 1
000 display oscillates between + and - This oscillation indicates proper
.

adjustment.
8

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 dc mV standard, or equivalent (Electronic Development
Corp. Model MV-1005), and a standard input jack.

3-32

Procedure

Step
1

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.
6

Set the EDC (mV standard) for 0.9850.

Set the OUTPUT selector to +.

Adjust the right GAIN potentiometer for a reading of +776 g

;

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 - 776 8

3.9

The optimum zero value should be an oscillating + - sign.

Set the EDC for 0.995V.

If the

Repeat the above procedure for the remaining channels.

GAIN is properly adjusted, the + and - values will equal 777 g

Location

Left Potentiometers

Right Potentiometers

E30

Channel 1 1

Channel 10

E31

Channel 13

Channel 12

E32
E3 3

Channel 15

Channel 14

Channel 1 7

Channel 1

EXTENDED ANALOG (AG12, AM 12)

3.9.1

Set-up Procedure

Channels 20 through 37 require an extra panel mounted on the bottom left of the PDP-1 2 Data Terminal Panel.

The cables plug into the following locations:
Channels

Location

20 through 27
20 through 37

F30

F31

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.
3.8.7 is used with the following addition:

SENSE SWITCHES set to 00=1

played.

3-33

;

The procedure in Section

Channels 20 through 37 will be dis-

3.9.2 Adjustment Procedure

Step
1

Procedure

Monitor Channel 20 by plugging the cables for the conversion box into F3
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 10 through 17.

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

3-34

CHAPTER 4
FIELD INSTALLATION AND

CHECKOUT OF PREWIRED OPTIONS

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

Table 4-1
Prewired Options

Name

Type

AD12
AG12
AMI 2
DP12-A
DP12-E

DR12
KE12
KP12
KT12

KW12-A
KW12-B
KW12-C
MC12
TC12
TC12-F

TU55
TU56
VC12

VR12
XY12
503

4.1

A-D Control
Preamplifier

Expanded Multiplexer
TTY Dataphone
TTY Dataphone (EEA-level)
Relays and Control
Extended Arithmetic Element
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

UNPACKING

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

Step
1

Unpack the kit and inspect it for any shipping damage.

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
1

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).
3

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

AD12

Time

Pre-Diagnostic Check

Option

CPTS3

5 min

AM12

INSTST

5 min

DP12-A

2 min

DP12-B

CPTS3
TTY1 and 2

N/A

AG12

DR12

2 min

5 min

CPTS3
INSTST

5 min

KE12

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

2 min

5 min

(continued on next page)

Table 4-2 (Cont)

Option MAINDECs Checklist

Time

Pre-Diagnostics Check

Option

MC12

CBL
CBH

5 min

ADDRSLO

5 min

ADDRSH1

5 min

rLll u

5 min

TC12

All tests applicable to PDP-12 configuration

Time is test-dependent

TC12-F

2A
CPTS2
CPTS3
TCI 2-1
TCI 2-2

2 min

MARK 12

As Required

PTP fOPY

2 min
2 min
5 min
5 min

fTTNTT fl -> TTNTT

1 0 min
Aj 1 VV^H KALI

t-VJ.

TU55

Power Checks

As Required

TU56

Power Checks

As Required

VC12

All tests applicable to PDP-12 configuration

N/A

XY12

2 min

CPTST
CPTS2
CPTS3

2 min

5 min
5 min

Table 4-3

Option Module and Cable List

AD12

AG12 2

Location

Note

Module

Option

A214(4-ea)

Preamplifier

E30, E31,E32,E33

A131 (2-ea)
A215
A404
A811

Multiplexer

D32, D33

Filter

D34

Sample & Hold

A/D Converter

E-F34
C-D35

M760

Control

C36

G783
G783

Analog Cable
Relay Cable

F33
F32

A214(8-ea)

Preamplifier

E26, E27, E28, E29, F26,

G783
G783

Channels 30-37

F30

Channels 20-27

F31

F27, F28, F29

Notes:

Panel AD 12 is shipped with both the AD 12 and DR12.

The AG 12 is a separate panel.

(continued on next page)

4-3

Table 4-3 (Cont)

Option Module and Cable List

Module

Option

A 1.31 (2-ea)

AM12

DP12-A

DP12-B 3

i^ndnneis jU j /

D30,D31
rJU

VJ / OJ

Ljianneis zu-z /

r5 1

G718

Jumper (110 baud)

M706
M707
W076

Receiver

Nil
M-N09
M-N10

M405
M706
M707
1V1
1

\J 1

M91
f\
1V1 LlU
WU/O

DR12 1

KE12

Location

V-J /

Note
Multiplexer

Transmitter
Table
Crystal

Receiver
Ttqi emit tpf
-

Nil
M-N09
M-T\J1
IVl-lN 1 n
u

nipriupsi

Ml
IN 1 7
Z

Cable

N03

M216

Flip-Flops

L04

G783
G783

Analog Cable

F33
F32

Relay Cable

Mil
Ml 13 (3-ea)
Ml 15 (2-ea)
Mil / t
M121
Ml 60 (3-ea)
M216
M906

Flip-Flops

M37

(Remove)

K27

ivr i z-

iVl /

ocnmiii i rigger

KT12

M117
M216

Flip-Flops

KW12-A

M103
Ml 13 (2-ea)
Ml 15
M117
M216 (2-ea)
M217 (3-ea)
M304 (2-ea)
M405

M7 19 (3-ea)

Notes:

L33

L35,L36,M33
L34, L29

MJ4, LiU
L31
L37, M35,M36

H27
H29
D24, D29

Amplifier

D23
D22
E09,F19
E03,E04,E07
D27, D28

Crystal

F18

Channel Select

F20, F21,F22

Flip-Flops

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

DP12-A - When the DP12-A is used to drive a Teletype at 1 10 baud, the M405 (location N 1 1 ) and
M216 (location N12) are not used. The G718 Module is placed in location Nil, thereby connecting
the PDP-12 Teletype to the DP12 input and output module.
DP12-B - When the DP12-B is used at other baud rates (0 -+ 10,000), the crystal clock (M405, Nil)
is selected

to be 128 times the baud rate.

For baud rates between 10,000 - 100,000, the wire from N12L2 to N12M1 is removed, and a wire
from N12L2 to Nl 1D2 is added. The crystal clock rate is then selected to be 16 times the baud
rate.

Use cable BC01 A-25 for interconnection to Dataphone.

(continued on next page)
4-4

Table 4-3 (Cont)

Option Module and Cable List

Option

KW12-A
(cont)

KW12-B

KW12-C

MC1

Location

Note

Module

F24

M503
M617
M623

Schmitt Trigger
Level Converter

D26

G783

Cable

W023

Jumper Board (Delete)

F25
E07

M401
M103
M870

RC Clock

F18

Selector

D25

Control

F25

M405
M103
M870

Crystal

Selector

F18
D25
F25

G020 (6-ea^

Delete

A07, A08, A09,B07,B08,

W023

Delete

M26

I\CMS l\JL d

A07, A08, A09,B07,B08,
B09
A13, B13, B14
A14, A15, B15

M216(3-ea)

Flip-Flops

M27
M28
M32
M29,M30,M31

M360
M617 (5-ea)
M720

Delay

E15
M22, M23, M24, M25, M26,

Non-Exist Memory

411

4K STACK

C-D11,C-D13

Sense Stack Cable

A-Bll
A-B12

jj i /

B09
G021 (6-eal

H99R H-paI
IVl 1 1 J>

M1
IVl 1 9
L1

M169

W025
W025
TP1 9

Inhibit Stack Cable

A35,C21
A33,C24,D16

O-en}

Ml 12 (3-ea)
Ml 13 C7-ea)

A26, A36, B24,B26, B38,

D29,C16
A27, A32,B27,B34,C25,

Ml 15 H-ea^l

C27 C29
5

M1
7 (R-en\
IVl 11/
\0 KsCL)

A25, A37, B33, B35, B36,
C23, E16, E17

Ml 19 (2-ea)

P99
A34 B25 B32 C26 E19

Ayr 1

f ^_**cA

M16U
M161
M169
M212
M222 (6-ea)

R9Q
Decoder
Flip-Flops

A29
A16
A38

Registers

A-B18, A-B19, A-B20,

M216(9-ea)

Flip-Flops

A-B21, A-B22, A-B23
A28, A30, B31,B37,D19,

M304 (5-ea)

Schmitt Trigger

C17,C18,C19,C20,D18

D20, E18,E20, E25

(continued on next page)
4-5

Table 4-3 (Cont)

Option Module and Cable List
Ontion

Nntp

IVf nHiilp

TC12

M307 (2-ea)
M401
M602
M617 (4-ea)
M901

(cont)

TP 9 -F
1

JL/UCd llOIl

C28, C30

Delays

E21
Schmitt Trigger

B30
A23, A24,B23,B28

Connector Cable

A40

G853
G882 (5-ea)

Unit Selector

F10

Readers/Writers

F04, F05, F07, F08, F09

W023
W032

Cable (Con)

E05

Cable

E-F06

W512(3-ea)

Level Converters

F13, F14,F15

W520
W603

Comparator

Fl 1

Amplifier

R107

Delay

F16
F12

MZ O

Flip-Flops

C32, C33

M101
M113
Ml 15

Interface

C38
D29

M2 16 (2-ea)

Flip-Flops

M711 (5-ea)
A615 (6-ea)
G783
G783

Control

D38, E38
C-D37
E-F36, E-F37
F38
F39

TU55 4
1

U JO

VC12

D/A Converter

VR 12 Cable
503 Cable

VR12

XY12

M704
W023

M-N05
N04

Control

Cable

503 4
Notes:

4. This option has modules already installed.

Remove the tape and install the cables as described in

Paragraph 4.2.1.

4.2.1

Installation of Panels and Cables

Panels are installed for the KW12-A, AG12, AD12, and DR12 options. These panels are installed on the PDP-12
as shown in Figure 4-1

Use the following procedure when mounting these panels:
Step
1

Procedure

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

0R12-A <

nrr
uti tadc
iMrt
STORAGE
RACK
#1809544
OR BLANK
PANEL
utv

TU55/56

Art

STORAGE
RACK

#1809544
OR BLANK

PANEL

KW12
PANEL OR

VR12

BLANK
PANEL

503

AD12 PANEL

PDP-12 CONSOLE

TABLE

\
DR12

PANEL
724
P/S

AM12
AG12
PANEL OR

BLANK
12-0260

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 KW12-A panel, a red wire will be taped to the cable on the back of the
Remove the tape and route wire to the ON/OFF switch. This wire is a
+ 10V tap from the switch to the panel. Locate + 10V on the switch and install
panel.

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.

1 1

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 TU55 and VR12

The TU55 (Figure 4-2) and VR12 (Figure 4-3) 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.

Step
1

Procedure

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.

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

Remove the blank snap brackets.
For mounting two TU55s and a VR1 2, mount clip-nuts and insert screws in
the 3rd, 6th, 1 1th, 14th, 19th, 22nd, 27th, 30th, 35th, 38th, 43rd, and 46th

holes on each side of the frame.
5

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 TU55 with cabinet brackets and slide unit in until it locks
(loud click will be heard).

CAUTION
The VR12 weighs 70 lbs; therefore, two men are
required to lift and install it in the PDP-12.

9
10

To install VR12, 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.
1 1

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

Connect TU55s together with ac cord in back of TU55 (3-ft cord). Connect
bottom TU55 to power supply (6 ft). Route last cable neatly and use tie
wrap when necessary.

(continued on Page 4-10)

4-8

4-9

Figure 4-4

TU55 and VR12 Mounting Assembly

Step

Procedure

Connect 3-ft dc cable to the top of the TU55 with green wire to +10V, black
wire to GND, and blue wire to - 15V connectors. Route cable to bottom
TU55 and connect as described above. Connect 6-ft dc cable to power

supply and route neatly (using tie wraps) to bottom TU55.

Ensure the TU55 transports can still be fully extended until they lock in the
maintenance position, without strain or interference with dc or ac cables.

Logic connection for the TU55s is as shown in Table 4-4. Cables such as
those in A6 and A3 through B3 are 3 ft in length. Cables in the A5 and A2

through B2 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 TU55 can be found in Paragraph 3.6.

The VR12 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 VR1 2.
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
M71 1 Display Module switches should be set as described in Paragraph 3.8.
Table 4-4
Interconnections of TU55

Top TU55 Location

Bottom TU55 Location

A6
A5

E05

A-B3
A-B2

E-F06

A-B3

4-10

Mem Logic Location

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
1

Performs Steps 1 through 4 of Paragraph 4.2.2.

Insert clip-nuts in both the front and rear frames in the 18th and 36th holes

(from the top). See Figure 4-6.
3

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

Figure 4-6 Front Assembly of TU5

FRONT FRAME

REAR FRAME

FRAME
SECTION

INSERT BOLT
IN THIS END

REAR PLATE
SUPPORT BLOCK

NOTE

Locate support block in 36th hole from the top.

Figure 4-7 Rear Plate Assembly of TU56

4-12

FRONT

FRONT
FRAME

REST PLATE
SUPPORT
BLOCK

REAR
REST PLATE

NOTE:
Screws A and B are located

Figure 4-8

the 36th hole from the top.

Top View of TU56 Rest Plate Assembly

Step

Procedure

Align (with help because of its weight) the bottom TU56 with the clip-nuts and
insert screws.

Tighten screws, using a long Phillips screwdriver.

1 1

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 TU56.

Connect dc cord to back of TU56 as in Table 4-5

Connect dc cord to power

supply.

CAUTION
With the TU56, the green wire is +5V, not +10V as
for the TU55. Be certain when connecting end of
cable in power supply, that green is connected to

+5V.
14

Connect ac cords 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 12, 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

Table 4-5

DC Voltage Connections
Voltage

Wire Color

-15V

Blue

GND

Black

+5V

Green

Table 4-6

TU56 Logic Cable Connections
Top TU56 Location

A06
A05

A06

A-B09
A-B10

A-B09

Mem Logic Location
E05*
E-F06

*This cable is not a 1-to-l cable.

4.3

Bottom TU56 Location

When inserting, place end marked TU56 in TU56 slot.

CHECKOUT

There are 20 prewired options for the PDP-12. The options (listed in Table 4-3) are checked out using the Adjustment Procedures in Chapter 3 and the write-ups supplied. Only the DP12-B, TC12-F, TU55, TU56 and VR12
options will be discussed here.

4.3. 1

Checkout of the DP12-B

Before commencing checkout of the DP12-B, determine the baud rate by using the following formulas.

For baud rates of 1 10 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 of M405 crystal

If the baud rate is in the

10,000 to 100,000 range, the wire from N12L2 to N12M1 is removed.

A jumper is then

Run PT08 Dataphone Test (DEC-08-D8PA-PB) for the ranges of 100 ^ 100,000.
For further information, see the PT08 test write-up (DEC-08-D8PA-PB).

installed from Nl 2L2 to Nl 1D2.

4-14

4.3.2

Checkout of TC12-F
Procedure

Step
1

Load the TC12-F diagnostic (MAINDEC-1 2-D3EA-P3) and, following the
instructions contained in the write-up, allow the test to run for ten minutes

minimum.
2

Load the TC 1 2-F conversion program PRTC 1 2-F ( 1 2-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 4-7).

Restart the LAP6-DIAL editor contained on the last converted PDP-12

format tape and type -> CL J

^AP; PRTC 2-F, 0 i
1

4
5

When the work area is clear, type

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

When the program has been added to the working area, type -> AS 2
When the program has assembled without an error, type LO }
Then depress I/O PRESET - LINC MODE - START 20. The first frame
.

of the PRTC 1 2-F program should be displayed. This completes the checkout and acceptance of the TCI 2-F option.

Table 4-7

Format Conversion Table

4.3.3

Read from Format

Block Number

Number of Blocks

Write to Format

Block Number

PDP-12
PDP-10

1000 8

526 8

PDP-10
PDP-12

Checkout of the LINCtape System

PDP-12 LINCtape Systems are comprised of the TCI 2 LINCtape Automatic Control; and,
a.

TU55 transports or,

TU56 transports or,

TU55 and TU56 transports together;

with or without a VR1 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

Display, use only the

VR12

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.

4-15

Step

Procedure

If the system has two TU55s or two TU56s, skip to Step 3.

If the system has a TU55 and TU56, check out both sections of the TU56

then do the TU55 with one TU56 section selected.

first,

Turn UNIT SELECT switches until UNIT 0 is the bottom (or right tape transport) and UNIT 1 is the top (or left tape transport).

Place LAP6-DIAL MAINTENANCE tape (DEC-12-D7AC-UO) on UNIT 0

and install a scratch tape on UNIT 1 as described in Paragraph 2.2.2.
5

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 2 program will be displayed on
1

the screen; skip to Step 10. If not, continue through Step 9.
a.

Displayed is the following:

- STD LINCTAPE FORMAT

2-128 WORD FORMAT
b.

Press Teletype key 1 for standard LINCtape format.

Press Teletype key LINE FEED to exit to

MARK 12 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).

GOOD COPY"

- 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 1 to the left about 3 ft.

1 1

When UNIT 0 stops, the following will be displayed.

PIP

—

A - AUXILIARY MODE
B - BINARY MODE
S - SOURCE MODE
12

TypeA$

)

(continued on next page)

4-16

Procedure

Step
13

PIP will then display the following:
PIP

C - COPY SPECIFIED BLOCKS

D - DUPLICATE UNIT 0 ON UNIT 1
S - COPY SYSTEM
14
1 5

TypeD J

UNIT 0 will rewind. Then UNIT will rewind to block 000 and begin
The approximate copy time is 5 min. If
copying UNIT 0 on UNIT
1

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

Reverse the UNIT SELECT numbers and repeat Steps 9 through 1 5

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

4.3.4

Checkout of VR12

The VR12 is illustrated in Figure 4-3. Table 4-8 contains a description of the front knobs and adjustments. Refer
also to Paragraph 3.8 for VR12 adjustments.

Table 4-8

VR1 2 Controls
Function

Control

CHANNEL

Selects one or both channels for scope display

BRIGHTNESS

Controls level of brightness

XGAIN
XPOS
YGAIN
YPOS

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 MARK12 displays. Check the displays for the following:

4-17

Evenness of lines

Continuity of lines and characters

Clarity of lines and characters

Focus

Brightness

Flicker

Ml 1

switch settings

4-18

CHAPTER 5
TELETYPE MAINTENANCE
MODELS ASR 33 AND 35

This chapter contains information pertinent to the maintenance of the Teletype Models 33 ASR and 35 ASR, and
associated control logic.

5.1

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
Part No.

Item

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

8 oz. scale

32 oz. scale

64 oz. scale
Set of gauges
Offset screwdriver

Offset screwdriver

Handwheel
Handwheel adaptor
Contact adjustment tool

Gauge
Gauge
Gauge
Bending Tool
Extractor

Tweezer
Spring hook (push)

Spring hook (pull)

Screw holder

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

Program Test

MAINDEC-8I-D2PB

Reader

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

MAINDEC-8I-D2QB

Punch

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

MAINDEC-8I-D2RB

Keyboard

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

MAINDEC-8I-D2TB

Combination

Exercisor program used to test simultaneously the

33 and 35 ASR Teletype printer and punch

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.
3

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
1

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

2
3

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

Procedure

Step

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 Number

Page Numfc

Trip Shaft

574-122-700

Trip Lever

574-122-700

Brush Holder (Distributor)

574-122-700

Clutches

574-122-700

Code Bar Reset

574-122-700

16-24
30-34

Print Suppression

574-122-700

Blocking Levers

574-122-700

Print Suppression

574-122-700

Carriage Drive Bail

574-122-700

Print Trip Lever

574-122-700

61-62

Dashpot

574-122-700

Final Printing Alignment

574-122-700

Line Feed

574-122-700

89-95

Keyboard Trip Lever
Reader Trip Lever

574-122-700
574-124-700

6-9

Detent Lever

574-124-700

Sensing Pin

574-124-700

Tape Lid Latch Handle
Feed Pawl

574-124-700

574-125-700

Registration

574-125-700

Part

5.3

141

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

Check that the tape holes are being punched cleanly.

CORRECTIVE MAINTENANCE

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 modified to operate with the PDP-12.

During off-line operation, the key-

board distributor effectively drives the printer selector magnet. As a result, any character received from the key-

board 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 TTI clock (880 Hz) and a TTO clock (220 Hz).

5-3

o
a
G
C
o

U
>.
•+-*

RANSMI

M707

H
>-

cvj

5-4

These clocks are used to shift the bits through the transmitter and receiver buffers. Adjustment is made by
viewing the TTO 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:
a.

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.

tact disk.

Reader, keyboard, and answer-back contacts provide parallel inputs to the distributor con-

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.

ACCUMULATOR

POP-12
4

START

UNIT

UN IT

UNIT

•

N " \ 7

UNIT UNIT UNIT
UNITS OF TIME |

UNIT

UNITS

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

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 com-

puter 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

Item

Quantity

Part Number

Circuit Board

18 1821

Tape Feed Sprocket

Lever, universal

182240
120167
180979
181420
181411
181409
181007
181002

Fuse (3. 2 A)
2

Distributor Brush

Belt-Driven Gear

Drive Gear

Belt

Shaft

Bearing

5-6

o
183071

APPENDIX A

MAINTENANCE AND SERVICE OPTIONS

Digital Equipment Corporation's Field Service organization offers a wide range of services for

DEC equipment

Customers may choose from a broad selection of service contract options and Per-Call Service or Depot

users.

Repair Maintenance plans to ensure optimum operating efficiency for their DEC equipment.

SERVICE CONTRACTS

A.l

Service 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. 1 1 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.

2 consecutive hours of on-call coverage

6 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.

work week.

The services of a resident engineer consist of 40 hours of coverage during the normal

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.

mum charge

A mini-

No inspection is required for service agreements
that are scheduled to commence immediately after the expiration of a standard DEC warranty or service contract.
is

associated with the pre-service contract inspection.

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

form 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 in-

form the DEC Field Service Office servicing the equipment of any special billing instructions related to the use of

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 deterper-call coverage.

mined 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,

future, incurred as a result of the performance of per-call service.

now in force or enacted in the

Installations enjoying tax exemption are re-

quested 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 options.

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:
a.

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.

charge is associated with a field installation.

A-3

A minimum

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.l

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-1 2 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 schematics, 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.
tions.

An acceptance procedure and accessory checklist are provided for such op-

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.

B.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-1 2 programs have been previously checked and
certified as being error free.

Successful completion of Sections B.4 and B.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 Acceptance 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. 1

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 equip-

ment 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.

CA DECUS INFORMATION
The DECUS information and introductory letter familiarizes the user with the Digital Equipment Computer Users
Society.

C.5

The letter invites membership and includes application forms.

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:
a.

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/, 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-1 2 System. The Key Sheet should be used to reference the
Master Drawing List (MDL) for each subsection (I/O, 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-1 2 Software, designating exactly what tapes and write-ups are involved in the
PDP-1 2 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-1 1). For a complete discussion of user programs available on the PDP-1 2, refer to Chapter 7 of PDP-1 2 System Reference Manual (DEC-1 2-SRZA-D) (note that later
revisions may be shipped).

PDP-12 SOFTWARE

NOTE
Document
-DN Document Change Notice
-D

-PA Paper Tape ASCII
-PB Paper Tape BINARY
-PM Paper Tape READ-IN-MODE
-UO LINCtape

LINC-8 PROGRAMMING MANUAL

I-L85

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

DEC-1 2-SE2D-UO
DEC-1 2-SE3A-UO
DEC-1 2-SE4A-UO
DEC-1 2-SE5A-UO

DEMO PROGRAMS

DEC- 1 2-UXZ A-UO
DEC- 1 2-MRZA-UO
MAINDEC- 1 2-D7AC-UO

MAINTENANCE PROGRAMS

MAINDEC-1 2-D8GA-UO
PDP-12 SIGNAL PROC. MANUALS
DEC-1 2-UW1A-D
DEC- 1 2-UW1 A-DL
DEC- 1 2-UW2 A-D
DEC-1 2-UW3A-D
DEC-12-UW4A-D
DEC-1 2-UW5 A-D
DEC-1 2-UZSA-D
DEC-1 2-UZ1 A-D

CATACAL
CATACAL ADDENDUM
ADTAPE AND ADCON
TISA
SINPRE

MAGSPY
SIGNAL AVERAGER USER'S GUIDE

(continued on next page)
D-1

PDP-12 SYSTEMS-DEMO MANUALS
PDP-12 SYSTEM REFERENCE MANUAL

DEC-12-SRZA-D
DEC-12-SE2D-D
DEC-12-FISA-D
DEC-12-FZFA-D
DEC-12-FZDA-D
DEC-12-ESYB-D

LAP6-DIAL MANUAL

FRED
MILDRED
CONVERT
LINC-8 SIMULATOR TRAP PROCESSOR

DEC-12-SI1B-D

MARK 12PATCH
CREF12
PRTC12-F

DEMO 12 USER'S GUIDE
DEMO 12 USER'S GUIDE ADDENDUM
DEMO 12 MONITOR SYSTEM TECHNICAL REFERENCE
MANUAL

DEC-12-Y1TA-D
DEC-12-YU2A-D
DEC-12-FRZA-D
DEC-12-YIYA-D
DEC-12-UXZA-D
DEC- 1 2-UXZ A-DN

DEC-12-MRZA-D

PDP-8 SYSTEM SOFTWARE

SOFTWARE PERFORMANCE SUMMARY

VOLUME 2: #3

SYSTEM USER'S GUIDE

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 -LB A A-D

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

DEC-08-LHAA-D
DEC-08-LRAA-D
DEC-08 -AFCO-D
DEC-08 -PMPO-D
DEC-08 -YXY A-D
DEC-08-YPPA-D

BINARY PUNCH
OCTAL MEMORY DUMP
PDP-12 MAINTENANCE MANUALS
PDP-12 CP TEST 2 (SKIP AND DATA HANDLING)

INSTRUCTION TEST PART
PDP-12 CP TEST 3
JMP SELF

PDP-12 CHECKERBOARD

FLOAT

& O'S THROUGH MEMORY
PDP-1 2 TAPE CONTROL TEST (PART of 2)
1 'S

VR12 DISPLAY TEST
A TO D TEST
PDP-12 RELAY REGISTER TEST
PDP-12 OPERATING PROCEDURE

MAINDEC-1 2-DOAB-D
MAINDEC-1 2-DOBA-D
MAINDEC-1 2-DOC A-D
MAINDEC-1 2-D1BA-D
MAINDEC- 2-D D A-D
MAINDEC- 2-D EA-D
MAINDEC-1 2-D3AE-D
MAINDEC-1 2-D6BA-D
MAINDEC-1 2-D6CB-D
MAINDEC- 12-D8AB-D
MAINDEC-1 2-D9C A-D
1

INSTRUCTION TEST
INSTRUCTION TEST 2

M AINDEC-8I-DO C-D

PDP-8 INSTRUCTION TEST PART 2B

MAINDEC-08-DO2B-D
MAINDEC-08-DO4B-D
M AINDEC-08-DO5 B-D

MAINDEC-8I-D02B-D

RANDOM JMP TEST
RANDOM JMP-JMS TEST

(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
FAMILY-OF-ASR 33/35 TELETYPE TESTS PART 1
FAMILY-OF-ASR 33/35 TELETYPE TESTS PART 2

MAINDEC-08-DO7B-D
MAINDEC-08-D1BO-D
MAINDEC-08-D1LO-D
MAINDEC-08-D1AC-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-AFC1-PB
DEC-08-AFA2-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 1 E-PB

PAL III
PAL III EXTENDED SYMBOLS

DEC-08-ASC1-BP
DEC-08-ASC2-PA

DDT-8

MACRO-8 LOW SPEED

DEC-08-CDDB-PB
DEC-08-CM A 1 -PB

ODT (LOW)
ODT (HIGH)

DEC-08-COC1-PB
DEC-08-COC2-PB

SYMBOLIC EDITOR

DEC-08-ESAC-PB

BINARY LOADER (2 COPIES)

DEC-08 -LB A A-PM

HELP BOOTSTRAP LOADER
HELP GENERATOR

DEC-08-LH A 1 -PB
DEC-08-LHA2-PB

READ-IN-MODE (RIM) PUNCH

LOW MEMORY -33
HIGH MEMORY RIM PUNCH -33

DEC-08-PMP1-PB
DEC-08 -PMP2-PB

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

DEC-08-YPPA-PB
DEC-08 -YX 1 A-PB

PDP-8 FLOATING POINT PACKAGE
BASIC PACKAGE (BASIC I/O PLUS
PACKAGE
1

INTERPRETER

PACKAGE 2: BASIC PACKAGE PLUS CONTROLLER
PACKAGE 3: BASIC PACKAGE PLUS EXTENDED FUNCTIONS
PACKAGE 4: BASIC PACKAGE PLUS CONTROLLER &
EXTENDER FUNCTIONS

DEC-08-YQ1B-PB
DEC-08 -YQ2B-PB
DEC-08-YQ3B-PB

DEC-08-YQ4B-PB

PDP-12 DIAGNOSTICS

MAINDEC- 12-DOAB-PB
MAINDEC- 12-DOBA-PB
MAINDEC- 12-DOCA-PB
MAINDEC- 12-D1BA-PB
MAINDEC- 12-D1DA-PB
MAINDEC- 12-D1EA-PB
MAINDEC- 12-D3AE-PB

PDP-1 2 CP TEST 2 (SKIP AND DATA TEST)

INSTRUCTION TEST 1
CP TEST III
JMP SELF
PDP-1 2 CHECKERBOARD
FLOAT 1 'S and O'S THROUGH MEMORY

TAPE CONTROL TEST

(continued on next

D-3

DISPLAY TEST (VR12)

DR12 RELAY REGISTER TEST

MAINDEC-1 2-D6BA-PB
MAINDEC-1 2-D6CB-PB
MAINDEC-1 2-D8AB-PB

INSTRUCTION TEST

M AINDEC-8I-DO C-PB

A-TO-D TEST

INSTRUCTION TEST PART 2B

MAINDEC-08-DO2B-PB

RANDOM TMP TF^T

iVl-rVirN LJIZiK^

m ATNnFr-na-noAR-PR
UO-L/vJH-DT D

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
FAMILY OF 8 ASR 33/35 TELETYPE TEST PART 2
TAPE CONTROL TESTS PART
PART 2
1

M AINDEC-08-DO5 B-PB
MAINDEC-08-DO7B-PB
MAINDEC-08-D1AC-PB
MA1NDEC-08-D1B1-PM
MAINDEC-08-D 1 B2-PM
MAINDEC-08-D1L1-PM
MAINDEC-08-D1 L2-PM
MAINDEC-08-D2PE-PB
MAINDEC-08-D2QD-PB
MAINDEC-1 2-D3AC-PB
MAINDEC-1 2-D3AC-D

Table D-l

Options Diagnostics

Mnemonic

DEC Number

PDP-12 Extended Memory

EXTMC12
writeup

DEC-12-D1AC-PB
DEC-12-D1AC-D

Tests Control Logics

Control

DEC-08-D1CA-PB
DEC-08-D1CA-D

Tests Control Logics

DEC-08-D 1 DA-PB
DEC-08-D 1 DA-D

Tests Extended Memory

DEC-08-D 1 H A-PB
DEC-08-D1HA-D
DEC- 12-D8E A-PB

Tests Addressing for

DEC-12-D8LB-PB
DEC-12-D8CB-D

Tests all Igoic for

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

Plotter Test

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

Plotter subroutine

writeup

EAE 3A

DEC-08 -DO A A-PB

Tests Extended

writeup

DEC-08-DOAA-D

Arithmetic Control

Option and Program Name

Use

MCI 2

Extended Memory

EXTMC

Control (81)

writeup

Extended Memory

EXTCB

Checkerboard

writeup

Extended Memory

EXTAT

Address Test

writeup

KW12-B-C

clock

KW12

KW12 D8CB

Clock Control test

writeup

Calcomp 1

Calcomp
writeup

Calcomp 2

OCALCOMP

for Extended Memory

Stacks for noise

Extended Memory Stacks

KW12

Tests

KE12

EAE Test, Part 3A

logic

EAE Test, Part 3B

EAE 3 B
writeup

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

More extensive test
of EAE Control logic
(continued on next page)

D-4

Table D-l (Cont)

Option Diagnostics

Mnemonic

DEC Number

FOCAL 4K

DEC-08-AFCO-PB
DEC-08-AFLO-D

Memory

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

Memory

Option and Program Name

FOCAL
FOCAL 4K

writeup

FOCAL 8K

writeup

PNRFAIL

KP12

Use

FOCAL using 4K of

FOCAL using 8K of

DEC-08-DIK1-PB
DEC-08-D1K1-D

writeup

Tests ability to retain

anu restart progrdin di tcr

power failure

KT12

Hardware test
Monitor Man.

DEC-T8-D8AA-PB^
DEC-T8-D8AA-D
DEC-T8-D8BB-D
DEC-T8-D8BB-PB
DEC-T8 -M RFB-D J i

Teletype tests

DEC-08-D2AA-PB'>

writeup

DEC-08-D2AA-D

Option test
writeup
writeup

DP12-A

Tests Time Sharing

System control logic
and hardware

Tests Dataphones
|

Extended Tape

rrmtrnl locric and

punch and read logic

writeup

DEC-08-D8PA-PB
DEC-08-D8PA-D J

PRTC12-F

DEC-1 2-YIYA-UO

Tape Conversion Test

TCV12-F

DEC-1 2-D3EA-PB

Tests TC12-F logic

Program

DEC-1 2-YIYA-D
DEC-1 2-D3EA-D

PT08 Test

DP12-B

Control

Extended Tape
Control

TC12-F writeup

Diagnostic

User Programs

DEC-12-SE2D-UO
Binary

Source

Name

BLKS

470
246
504

PIP

L8SIM
DIAL-MS

MAGSPY

BLKS

247

656

122

MARK 12

171

PATCH
PRTC 2-F

542
566

CONVERT

142

DIAL V2
DIAL-MS4

245

47
24
65

DIAL-MS3
DIAL-MS2

114

20
(continued on next page)

D-5

DEC-12-SE2D-UO (Cont)
Binary

Source

Name

BLKS

DTAL-MS1

GENASYS
CATACAL
SIGAVG

711

SINPRE

CNTRL2
CNTRL4
DIALMS

653

BLKS

54
240
665

20
5

DEC-12-SE3A-UO

Name

Binary

Source

BLKS

PIP

MARK 12
FOCAL4K
FOCAL8K

173

172

534

L8SIM

QANDA
CONVERT
MAGSPY
DIALV2

FORCOM
FRED
FORSYS
BINLOAD
PATCH

226
206
702
205
201

FMC8-PA

FMDA-PA
FMEA-PA
FMFC-PA
FMGB-PA
FMHA-PB
FMIA-PA
FMJA-PA

FMKA-PA
IOUASCII
11UASCII
15UASCII
14UASCII

7
;

116
207

213
520
216

553
525

154

202

Z't J

230

617

642

176
573

577

145

607

142

2
1

635

112

645

21-U-BIN

21UASCII
19UASCII
18UASCII

631

247
470
477

530

227
626
532
212

BLKS

PRTC12-F

FMAA-PA
FM8A-PA

107

103

(continued on next page)

D-6

DEC-12-SE3A-UO (Cont)

Name
22 UAoCll
O^TT A QPTT
O/ITT A C/^TT

OOT
T A QfTT
2yUAS>Cll
CT T \ OPTT
25UAaCll
28UASCII
<-)

Source

Binary

BLKS

652
76

BLKS

742
20

655
64

663

673

MILDRED
YQIA-PB
YQ2A-PB
YQ3A-PB
YQ4A-PB
25F-EAE1
25F-EAE2
25F-EAE3
25F-EAE4

745
55
45

756

7
7

DEC-12-SE4A-UO

Name

Binary

Source

BLKS

252

242
232
220
536

ADTAPE

ADCON

470

SIGAVG1
SIGAVG2
SIGAVG4

NMRSIM

NMR2
NMR3

556

40
52

CAT2
CAT3

630

160

SINPRE

10
12

715
727

CAT IE
CAT1

736

DEC-12-SE5A-UO

Name

Binary

Source

BLKS

470

TIP2

173

MILDRED
NMRSIME
CATACALE

563

TISA
TIP1

BLKS

250

153

132

(continued on next page)

D-7

Demonstration Programs

DEC- 1 2-UXZ A-UO
Binary

Source

Name

BLKS

LOADER.
SEG01-3.

SEG11-4.
INITLIZ.

A
4
1

GREETIN.

BALLOON.

9
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SEG04-4.

1 /

DMOINDX.

99
ZZ

9
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Q AND A.
.DA-DTST

•

9
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Z4
9A
Z4

A
4

.DFRQANA

.DDIAL
.FFREQ12

1
1

63
UJ

46
50
52

170

173

176

201

206
210
216
220
993
996

.DDATA12
.DMAGSPY

.EWAVES
.EB.BALL

.EBASMEM
.FSOLACE

.FMUSIC
.FKALEID

54
56
J
KJ

.FDRAW12
.FECHASK
.FSPCWAR

j i

9
z

.TDAYCOM

.TSTPWCH
.TCLOCK
SCRATCH.

9
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H/ 1

IKJj

1 £1

263

522

GREETING
INDEXSRC
DIAL-V2

£ 1 1
J
1 1

Aid
4 U

AD DEMO

^?
1

6
O

PIP
i

2
3

9^n
ZjU
Zjo
/

jZo
cot/
DZ

MARK12
EX.PROG.

JZU

ZI
9
Z

014

BINLOAD

JjJ

L8SIM

JH-U

CONVERT
FOCAL8K
FOCAL4K
CAROLS
LOADER

543

635

INITLIZE

641

SEGO

663

SEG1

725

550
573
617
637
660
717
763
771

BALLOON
04-01-70

527

21
11

2
3

(continued on next page)

D-8

DEC-12-MRZA-U0
Source

Name

OMAGSPY
T\ T» A 117 1 <~\

DRAW 12
KALIED

Binary

BLKS
u l rv

160

540
520

REMAKE
BALLOON
H-DIAL
"nn
X
H-FRQANA

514
515

H-FREQ12

521

T A

H-B.BALL

517

H-ECHASK

523
527

H-DAYCOM
H-STPWCH
H-DRAW12
H-SOLACE
H-CLOCK

H-BASMEM
H-MAGSPY

141

507

2
1

530

531

533

534

561

137

H-A-DTST

136

DATA 12
ECHASK

244

535

H-DATA12

621

MARK 12

127

PIP

470

EX.PROG.

525

AD DEMO

LOADER

526
630
635

INITLIZE

102

557
546

SEGO

637

613

SEG1

44
217
562
263

36
25

551

KW12SUBC

STPWCH

FROANA
INDEXSRC

31
5

Maintenance Programs

DEC-12-D7AC-UO (basic diagnostics)

Name

Binary

Source

BLKS

251

470
477
502

MARK 12

604
603

RIMLDR

605

BINLDR
CBL
CBH

606
607
104

505
245

ADDRSLO

612

510

PIP

3
3
3

(continued on next page)

D-9

DEC-12-D7AC-UO (Cont)
Binary

Source

Nornp

BLKS

ADDRSHI
ADDRS12

103

241

611

513

RANISZ

101

515

n
A XT TTkjf T*
RANJMF

102

235

522
233

1
1

231

2
13

526
217
203

541

547

JMPJMS
T7 T T?
JMPSLLr
T ft <f"r»0

MbMDAATA
1

AyrTTTi/TlA

T\TCT 1

1NST1

TMCTO A
TXTCTOD

t? A

COD

100
610
613
614
77
726
602
106

1
1

105

CPTSTl
CPTST2
CPTST3

TTY1

TTY2
TC12F
DP12A
PWRFAIL

EXTMC
EXTAT
EXTCB

EXTMC
TAPECNTL
ADTST
RELAYTST
1

712
713
725
714
715
30
27
716
717
720

167

564

146

131

I
1

721

799

570

615

121

630
577

14
3

113

644
654

10
11

107
S6

34
723

665

672

DISPTST

KW12TST
KW12BC

724
727
32

676
46
702
707

ONOFF
CALCOMP

4
10
5

DEC-12-D8GA-UO (option diagnostics)
Binary

Source

Name

BLKS

PIP

251

MARK 12

RIMLDR
BINLDR

470
477
502
505

DB12
DC02
DC04

HSRDPUN
DF32DD

40
250

242
512
230
523

147
155

154
150

3
3

6
11

12
21

(continued on next page)

D-10

DEC-12-D8GA-UO (Cont)

Name

DF32DL
T> T?f\0 T\T\

Source

BN
i

Binary

BLKS

604

]

BLKS

216
203
544

RF08MD
LINEPNTR

605

177

CARDREAD

151

PECITRE

146

PECITIT

145

PECITDRT
PECITDT

144

557
170
565
156
576

152

143

D-ll

6
7
11

12
6

INDEX

Customer Programs, B-l

D/A (AD 12) Adj. & Checks, 3-26
D/A Adj. Procedures, 3-27

Diagnostics, B-l

Daily Maintenance, 2-4

Software, B-2

Data Forms, Customer, C-l

Acceptance

Forms, Customer, C-l

DECUS Information, C-2

Testing, B-l

Demonstration Programs, List, D-8
Acoustical Damping, 1-4

Depot Repair, A-2

A/D Adjustments, 3-30
A/D Sample & Hold Adj., 3-30
Adjustments, Chapter 3, 3-1

Diagnostics

Memory, 3-8
Prewired Option Software List, D-l

Memory Current & Strobe, 3-1
Air Conditioning, 1-4

Display
Brightness & Preset Adj., 3-29

Analog Adj., Extended, 3-33

Size

Analog and Display Adj. & Checks, 3-26

(VR12) Adjust. & Checks, 3-26

Analog Channel Adj., External, 3-32

& Position Adj., 3-29

DP12-B Checkout, 4-14

B
BIN, Loading, 1-17

E
8-Mode Processing, 2-9
Environmental Consideration, 1-4

Equipment
Checklists, Optional, C-2

Cabinet

Maintenance, 2-1
Installation, 1-13, 1-5

Inspection, 1-13

Unpacking, 1-12
Cabling, 1-11
Checklist, Software, C-2

Checkout, 1-15

Expanded Equipment Layout, 1-7
Expansion, System, 1-6

Extended Analog Adj. (AG12, AM12), 3-33
Extended Memory MCI 2 Adjustments, 3-7
External Analog Chan. Adj., 3-32

Checks

Console, 2-7

8-Mode Processing, 2-9

LINC-Mode Processing, 2-8
TCI 2 Console, 2-10
TCI 2 Tape Sub processor, 2-9
Circuit Breaker CB1, 1-15
Cleanliness, 1-5

Configurations, System, 1-5

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-l

Console Checks, 2-7

Constraints, Installation, 1-4

Corrective Maintenance, 2-5

Teletype, 5-3

Customer Acceptance, B-l

Humidity, 1-4

INDEX (Cont)

Test Programs, 2-2
Tools, Teletype, 5-1

I/O Interface, 1-6
Initial

Memory Current Adjustments, 3-1

Initial Strobe Adjustments, 3-2

Mark Clock Adj., 3-16

Memory
Current Adjustments, Initial, 3-2

Inspection

Current Adjustments, Final, 3-4
Cabinet, 1-13

Current and Strobe Adjustments, 3-1

Peripheral Equipment, 1-15

Diagnostics, 3-8

Installation, 1-1

Extended, Adjustments, 3-7
Margins & Final Strobe Adjustments, 3-6

Cabinet, 1-13

Options, 1-15

Strobe Adjustments, 3-2

Prewired Options, 4-1

Tests, 1-16

Teletype, 1-14

Module Troubleshooting, 2-12

Constraints, 1-4

Mounting LINCtape, 2-3

L
LAP6-DIAL Maintenance, 3-29

LAP6-DIAL MAINTENANCE Tapes, Mounting, 2-3
Lighting, 14

O
Operating Checks, Preliminary, 1-15

Option
Checkout, 4-14

LINC-Mode Processing, 2-8

Installation, 1-15

LINCtape

Module and Cable List, 4-3

ACIP Delay Adj., 3-14

Optional Equipment Checklists, C-2

Adjustments, 3-9

Options

LTD Tape Fail Delay Adj., 3-13
LTD TTOK Delay Adj., 3-12
LTD XTLK Delay Adjustments, 3-1

DEC Field Installation, A-3
MAINDEC list, 4-1

System Checkout, 4-15
P

Loading
BIN, 1-17

Packing Details, 1-8

RIM Loader, 1-16

Panels & Cables, Installation of, 4-6

Log Book, 2-14

Pedestal Type Flooring, 1-1

Logic Troubleshooting, 2-12

Peripheral Inspection, 1-15

Planning, Installation, 1-1

M
MAINDECs, Loading, 1-17
Maintenance, Chapter 2,2-1
Corrective, 2-5
Daily, 2-4

LAP6-DIAL, 3-29
Preventive, 2-3

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

Scheduled, 2-4

Weekly, 2-4
Service Options, A-l

Predelivery Preparation, 1-6

Preliminary Operating Checks, 1-15

Equipment, 2-1

Preparation, Predelivery Procedures, 1-6

Programs, list of, D-9

Preventive Maintenance, 2-3

Programs, Teletype, 5-2

Teletype, 5-2

Tasks, Preventive, 2-4

Tasks, 2-4

INDEX (Cont)

P (cont)

Space Requirements, 1-1
Special Mounting Considerations, 1-4

Prewired Options
Specifications, Power Supply, 2-5
Installation, 4-1, 1-15

Software Diagnostics, D-l

Standard Configurations, 1-5

List of, 4-1

Strobe Adjustments, 3-2

Unpacking, 4-1

System

Checkout, 4-14

Configurations, 1-5

Printer/Punch Corrective Maintenance, 5-5

Expansion, 1-6
Layout, Planning, 1-3

Programs

Power Requirements, 1-9

Customer, B-l

Demonstration list of, D-8

Troubleshooting, 2-6

Maintenance list of, D-9

Maintenance Test, 2-2
User list of, D-5

Tape Timing Pulses Adjustment, 3-9

TC12-F Checkout, 4-15

TCI 2
Raceway Type Flooring, 1-2

Console Checks, 2-10

Receiving Constraints, 1-8

Tape Subprocessor Checks, 2-9
Teletype

Receptacles, Power, 1-10

Repairs & Replacements, 2-13

Clock Adjustments, 3-8

Requirements, Power,

Console Installation, 1-14

1-9

Corrective Maintenance, 5-3

RIM Loader, Loading, 1-16
Running MAINDECs, 1-17

Equipment, 5-1
Installation, 1-14

Keyboard Spares, 5-6
S

Maintenance, 5-1

Maintenance Programs, 5-2
Safety and Fire Precautions, 1-3

Scheduled Maintenance, 2-4
Service Contracts

Depot Repair, A-2
Eligibility, A-2
Options, A-l
Per-Call Coverage, A-2

Service Outlets, AC, 1-11

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,

Shipping and Receiving Constraints, 1-8

Computer Memory, 1-16

Shipping Methods

Teletype, 1-16

Domestic & North America, 1-8
Overseas & Air Freight, 1-9
Site Considerations, Planning, 1-1

Software

Validation, 2-14

Trouble Reports, Software, C-l
Troubleshooting
Logic, 2-12

Acceptance, B-2

System, 2-6

Prewired Option Diagnostics,, D-l

Modules, 2-12

Checklist, C-2

Trouble Reports, C-2

Techniques, 2-6

TU55

Soldering Techniques, 2-14

Brake Adj., 3-18

Source Power Requirements, 1-9

Head Installation, 3-22

INDEX (Cont)

T (cont)
TU55 (cont)
Head Removal, 3-22
Head Skew Adj., 3-22
Interconnections, 4- 1

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, 4-1

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, 4-17
Deflection Adj., 3-30

Display Focus Adj., 3-30
Size

& Position Adj., 3-29

Unit and Cable Installation, 4-8

W
Weekly Maintenance, 2-4