Digital Equipment PDP-8/A Service manual

EK-SA001-0P-002
PDP-Sf A OPERATOR'S HANDBOOK
digital equipment corporation •maynard.massachusetts

PDP;;;8/A OPERATOR'S HANDBOOK
digital equipment corporation •maynard.massachusetts

18t Edition, September 1975
2nd Printing (Rev), September 1976
Copyright © 1975, 1976
by Digital Equipment Corporation
The material in this manual is for informational
purposes and
is subject to change without notice.
Digital Equipment Corporation assumes no respon-
sibility for any errors which may appear in this
manual.
Printed in U.S.A.
This document was set on DIGITAL's DECset-8000
computerized typesetting system.
The following are trademarks
of Digital Equipment
Corporation, Maynard, Massachusetts:
DEC
FLIP CIllP
DIGITAL
UNIBUS
DEC US
PDP
FOCAL
COMPUTER LAB
MASSBUS

CHAPTER 1
CHAPTER 2
2.1
2.2
2.2.1
2.2.2
CHAPTER 3
3.1
3.2
3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.5
3.4.6
3.4.7
3.4.8
3.4.9
3.4.10
3.4.11
CHAPTER 4
4.1
4.2
CHAPTERS
5.1
5.2
5.3
5.4
CHAPTER 6
6.1
6.2
6.3
6.4
CHAPTER 7
7.1
CONTENTS
INTRODUCfION
PACKING AND UNPACKING INSTRUCTIONS
UNPACKING INSTRUCTIONS
PACKING INSTRUCTIONS
BA8-C Chassis Assembly .....
Other PDP-8/A Chassis Assemblies
SYSTEM DESCRIPTION
Page
2-1
2-1
2-1
2-3
GENERAL
....... . . . . . . . . . . . . . . . . . . . . .. 3-1
CHASSIS DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . .. 3-4
EXPANSION TECHNIQUES . . . . . . . . . . . . . . . . . . . . .. 3-8
PDP-8/A MODULE DESCRIPTIONS ..................... 3-9
KK8-A Central Processor Unit (CPU)
.................. 3-9
MS8-A Read/Write Random Access Memory (RAM) .......... 3-11
MR8-A Read-Only Random Access Memory (ROM)
.......... 3-12
NHvI8-AA 8K Core Memory . . . . . . . . . . . . . . 3-15
MM8-AB 16K Core Memory . . . . . . . .
...... 3-16
DKC8-AA I/O Option Board
....... . .... 3-18
K~M8=A Extended Option Board .... ... . . . . . .... 3-22
Semiconductor Memory Power Supply . . . . . . . . . . 3-25
Core Memory Power Supply Regulator
........... 3-26
Limited Function Panel
................... . .... 3-29
KC8-AA Programmer's Console
........ . . . . . . . . . . . 3-30
INSTALLATION AND INITIAL POWER TURN-ON
ENVIRONMENTAL AND POWER REQUIREMENTS
INITIAL POWER TURN-ON ............ .
TESTING PDP-8/A WITHOUT PAPER TAPE DIAGNOSTICS
4-1
4-1
PROGRAMMER'S CONSOLE ........................ 5-1
CENTRAL PROCESSOR TEST ROUTINES ................. 5-1
ENTERING TEST ROUTINES FROM PROGRAMMER'S CONSOLE .... 5-1
CENTRAL PROCESSOR TEST ROUTINES . . . . . . . . . . . . .. 5-2
LOADING THE RIM AND BINARY LOADERS
LOADING RIM LOADER
.......... .
CHECKING THE RIM LOADER
....... .
LOADING THE BINARY LOADER ..... .
LOADING BINARY FORMATIEDPAPER TAPES
. . . . . . .. 6-1
6-2
6-2
6-3
TESTING THE PDP-8/A USING MAINDEC DIAGNOSTIC PROGRAMS
CENTRAL PROCESSOR UNIT (CPU) TEST
.. 7-1
iii

CHAPTER 8
S.l
S.2
S.3
S.4
CONTENTS (Cont)
ADDITIONAL DIAGNOSTIC TESTS
MEMORY TEST
......... .
DKCS-AA TEST . . . . . . . . . . .
KMS-A EXTENDED OPTION BOARD TEST
TESTING EXTENDED MEMORIES
CHAPTER 9 BASIC PDP-8/A MAINTENANCE
APPENDIX A INSTRUCTION SUMMARY
APPENDIX B DOCUMENTATION
APPENDIX C WARRANTY AND MAINTENANCE SERVICES
APPENDIX D
OMNmus LOADING
APPENDIX E POWER CONNECTION
Figure No.
2-1
2-2
2-3
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-S
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-17
3-1S
ILLUSTRATIONS
Title
SA420, SA620, SAS20 Packaging .
PDP-S/A Computer Packaging (Inner)
PDP-S/A Computer Packaging (Outer)
PDP-8/A Computer
........ .
Part of MS320 Module Showing R55, Which is Removed for SA Operation
PDP-8/A Semiconductor Chassis
.......... .
PDP-8/A Semiconductor Computer Chassis Dimensions
SA Chassis -H9300 (Transformer Cover Removed)
SA620 Chassis . . . . . . . . . . . . . .
SA420/SA620/SAS20 Chassis Dimensions
SA600/SA620 Expansion ....... .
KKS-A (MS315) CPU Module ..... .
MSS-A (MS311) Read/Write Random Access Memory
MRS-A (MS312) Read Only Memory (ROM)
MMS-AA SK Core Memory
.....
MMS-AB 16K Core Memory . . . . '. . . . .
DKC8-AA (MS316) I/O Option Board
D
Etch Revision of DKCS-AA (MS3l6) I/O Option Board
KMS-A (MS317) Extended Option Board .....
Semiconductor Memory Regulator Board (GS016)
SA Master/Slave Switch
............. .
iv
Page
S-l
S-2
S-6
S-9
Page
2-2
2-4
2-5
3-1
3-3
3-4
3-5
3-6
3-7
3-S
3-9
· 3-10
· 3-11
· 3-13
· 3-15
3-17
· 3-18
· 3-19
.. 3-20
3-25
· 3-27

Figure No.
3-19
3-20
3-21
6-1
6-2
E-l
Table No.
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
8-1
8-2
9-1
ILLUSTRA nONS (Cont)
Title
Core Memory Regulator Board (G8018)
Limited Function Panel .....
KC8-AA Programmer's Console
Paper Tape Leader ....... .
LT33 Teletype Controls
..... .
PDP-8/A Electrical Connection
TABLES
Title
PDP-8/A Computer Assemblies . . . . . . . . . .
PDP-8/A Computers, Dedicated Omnibus Slots
....
KK8-A (M8315) Central Processor Unit Switch Settings
MS8-A Read/Write Memory Switch Settings
MR8-A Read Only Memory Switch
SettLl1gs . . .
MM8-AA 8K Core Memory Jumper Installation .. . . . . .
MM8-AB 16K Core Memory Jumper Installation
DKC8-AA I/O Option Board Switch Settings, C-Etch Module
DKC8-AA Option Board Switch Settings, D-Etch Module . .
Auto-Restart Select Switch Settings .. . . . . . . . . . . .
Bootstrap Select Switch Settings for ROMs Labeled 87A2 and 88A2
Page
· 3-28
· 3-29
· 3-30
6-2
6-3
E-l
Page
3-2
3-3
· 3-10
.. 3-12
· .. 3-14
..... 3-16
· .. 3-16
· 3-20
..... 3-21
.. 3-23
· 3-23
· 3-23
· .. 3-24
Bootstrap Select Switch Settings for ROMs Labeled 158A2 and 159A2
Bootstrap Select Switch Settings for ROMs Labeled 156A2 and 157A2
Bootstrap/Auto-Restart Switch Settings . . . . . . . . . . . . .....
Bootstrap Switch Settings for ROMs Labeled 87 A2 and 88A2 (E82 and E87)
Bootstrap Switch Settings for ROMs (E82 and E87) Labeled 158A2 and 159A2
3-24
8-8
8-8
9-1
Basic PDP-8/A Troubleshooting ....................... .
v

CHAPTER 1
INTRODUCTION
There are two basic types of computers in the PDP-8/A family. The first type is the PDP-8/ A, which uses
semiconductor memories (MS8 and MR8). The second type
is represented by a series of computers, each of
which uses 8K or 16K core memory (MM8); this series consists of the 8A400, 8A420, 8A600, 8A620, 8A800, and
8A820 computers. When a reference applies to both types
of computers, the designation "PDP-8/ A" is used.
"PDP-8/A semiconductor" refers to the semiconductor memory computer, while "8A400," for example, refers
to a specific core memory machine and
"8A" refers to the core memory machines in general.
The
PDP-8fA Operator's Handbook includes instructions for packing, unpacking, and installing a PDP-8/A
miniprocessor. All computers and modules are tested thoroughly at DIGITAL's manufacturing facilities before
they are shipped. However, many switches andjumper wires can be arranged
by the customer for specific pur-
poses; furthermore, there
is a need both to verify system interconnections and site preparations, and to detect
possible hidden damage incurred during shipping. Consequently, a number
of initial operating tests are also
included in this handbook.
A
PD P-8 /A basic system can comprise a variety of components. The following three basic systems are the most
common:
1. A basic PDP-8/A,*a memory, and a Limited Function Panel. (This computer does not include a KM8
Extended Memory Option module and, hence, must be a PDP-8/A semiconductor.)
2. A basic PDP-8/A, a memory, a Limited Function Panel, a KM8 Extended Memory Option module,
a DKC8-AA
I/O Option module, and a Programmer's Console. (Chapter 5 describes operating tests
for this arrangement.)
3. A basic system as described in 2, but accompanied by a teletypewriter and diagnostic** programs.
(Chapter 7 describes operating tests for this arrangement.)
*A basic PDP-8fA is defmed as a Central Processor Unit (CPU) and a chassis assembly (chassis, Omnibus, and power supply).
**Diagnostics are test programs written
to fmd faults in the logic. The PDP-8fA programs are supplied on paper tape. Diagnostic pro-
grams are optional and may be ordered from the Software Distnoution Center, 146 Main St., Maynard, MA, 01754.
1-1

2.1 UNPACKING INSTRUCfIONS
CHAPTER 2
PACKING AND UNPACKING INSTRUCTIONS
All PDP-8 fA computers are packaged in two containers; the inner container holds the computer and some kind
of protective material. The steps in this section are sufficiently general to apply to any PDP-8fA.
To unpack the PDP-8fA computer, proceed as follows.
i. Open the outer carton and remove the inner carton.
2. Open the inner carton.
3. Carefully remove the cardboard from the top and sides of the computer.
4. Carefully remove the computer from the box.
5. Inspect the computer for damage. If the computer is damaged, notify the carrier immediately.
6. Unpack any other boxes included in the shipment.
7. Check that all equipment, software, manuals, etc., are present as specified on the shipping list inside
the carton.
8. Save the cartons and packing material to use if the PDP-8fA is later repacked.
9. Refer to Chapter 4 for PDP-8fA installation procedures.
2.2 PACKING INSTRUCTIONS
Two types of packages are used for the PDP-8fA computers. The type used and the applicable packing instruc-
tions depend on the type of PDP-8fA chassis assembly.
2.2.1 BA8-C Chassis Assembly
The 8A420, 8A620, and 8A820 computers use a BA8-C chassis assembly (20-slot Omnibus). Figure 2-1 illustrates
the packing procedure. The computer is first placed in the inner container (9905417), the empty space is filled
with plastic protective material (AIR CAP, SD-120), and the container is sealed. The sealed inner container is
surrounded with protective foam material which is then enclosed by the two telescope caps. Finally, the package
is secured by two plastic straps.
2-1

FULL TELESCOPE CAP
(9905647)
FOAM PAD
(9905648)
PACKAGED OPTION IN BOX
(9905417)
FULL TELESCOPE CAP
(9905647)
Figure 2-1 8A420, 8A620, 8A820 Packaging
2-2
FILL VOIDS IN CARTON
WITH AIR CAP SD-120
FOAM CORRUGATED
SIDE
WALL ASS'Y
(9905641 )
ust: (2) PLASTIC STRAPS
(1) IN EACH DIRECTION
TO HOLD CONTAINER
TOGETHER.
08-1789

2.2.2 Other PDP-8/ A Chassis Assemblies
CAUTION
The G8016 Regulator Board assembly used on PDP-8/A
semiconductor computers contains a battery. This battery,
while not of sufficient t'oltage to cause electrical shock,
represents a possible hazard if shorted. If repacking this
type computer, ensure that there is no loose metal, such as
solder, wire, or sheet metal parts, inside the cabinet.
The PDP-8fA semiconductor computer and the 8A400, 8A600, and 8A800 computers use a chassis assembly that
has a lO-s10t or 12-s10t Omnibus. To pack these computers, proceed as follows.
1. Place the computer in the smaller of the two shipping cartons with the back (side with power cord) of
the computer against the side of the carton.
2. Place the beveled die-cut sheet with foam protector (part number 9905675) in front of the computer
(Figure 2-2). If the Limited Function Panel and a pop panel are on the computer, the beveled edge
should be down inside the carton. If the computer has a Programmer's Console, the beveled edge
should be up so that the cut-out in the cardboard fits the Programmer's Console.
3. Place the die-cut sheet with foam saddle (part number 9905677) downward over the computer. The
end with two pieces of foam should be fitted around the fans and the other end should be positioned
so that the cardboard fits behind the cabinet mounting flange and the foam is against the side of the
carton.
4. Close the flaps and seal the carton with tape.
5. Surround the sealed carton with protective foam material and enclose with telescope caps (Figure 2-
3).
6. Strap in both directions using steel or plastic strapping.
2-3

DIE -CUT SHEETS
WITH FOAM BEZEL
PROTECTOR
(9905675J
DIE-CUT SHEET
WITH FOAM SADDLE
(9905667]
REGULAR SLOTTED
CARTON (9905649)
08-1494
Figure 2-2 PDP-8fA Computer Packaging (Inner)
2-4

FULL TELESCOPE CAP
(9905662)
FOAM PAD
(9905663)
PACKAGED OPTION IN BOX
(9905649)
FOAM PAD
(9905663)
FOAM CORRUGATED
SIDE WALL ASS'Y
~ (9905661)
~
Figure 2-3 PDP-8fA Computer Packaging (Outer)
, 2-5
08-1790

3.1 GENERAL
CHAPTER 3
SYSTEM DESCRIPTION
A PDP-8/ A computer is pictured in Figure 3-1, which shows both the Limited Function Panel (the panel on the
bottom with three switches and three indicators) and the Programmer's Console. The Programmer's Console can
be located remotely from the chassis; in such a case,
or when the system does not include a console, a blank panel
is attached instead. Both the panel and the console are latched to the chassis; they can be removed by pulling
them off the latches. (Do not pull too vigorously; the panels are attached by cables to interior points.) When the
panels
are removed, the module boards are visible.
7288-5
Figure 3-1 PDP-8/A Computer
3-1

The PDP-SI A computers have three different mechanical assemblies that can be characterized by the number of
available Omnibus slots; that is, the PDP-SI A semiconductor computer assembly has a IO-slot Omnibus, while
the
SA computer assemblies have either a 12-slot or a 20-slot Omnibus. Table 3-1 relates the various PDP-SIA
computers to some of the basic system components. Note that the SA400 can be considered to be the basic SA
computer, having a core memory, an SA CPU, and a 12-slot Omnibus. Thus, the SA420 differs only in that it has
a 20-slot Omnibus; the SA600 differs in
that it has a PDP-S/E CPU; the SA620 differs in that it has a PDP-S/E
CPU and a 20-s10t Omnibus; the SASOO differs in that it has an FPP-SA (not indicated in Table 3-1); and, the
SAS20 differs in that it has an FPP-SA and a 20-s10t Omnibus. Also, note that only the SA computers that use a
PDP-S/E CPU can be expanded.
Table
3-1
PDP-8fA Computer Assemblies
Computer
CPU
Memory* Basic Power Assembly Omnibus Expandable ?
PDP-8fA
KK8-A Semiconductor H763 H9192
(1 O-sIot)
No
8A400
KK8-A Core H9300 H9194 (12-s10t)
No
8A420
KK8-A Core
BA8-C
H9195 (20-slot) No
8A600
KK8-E Core
H9300 H9194 (12-slot)
Yes - as many as 20
slots can be added
8A620
KK8-E Core BA8-C
H9195 (20-slot)
Yes - as many as 20
slots can be added
8A800 KK8-A Core H9300 H9194 (12-slot)
No
8A820
KK8-A
Core
BA8-C H9195 (20-slot)
No
*A KMS-A (or KMS-E) Extended Memory Option module must be included in all the SA computers, since their basic memory capacity
is SK or 16K; the KMS is optional with the PDP-SfA semiconductor computer, since the basic memory capacity can be less than,
greater than, or equal to 4K.
In addition to the CPU, most DIGITAL PDP-S/E options will operate with the PDP-S/A computers. The
following will not:
1. KPS-E Power Faill Auto-Restart option
2. DKS-EA Line Frequence Real-Time Clock option
3. MMS-E 4K Core Memory
4. MMS-EJ SK Core Memory
The KES-E option (Extended Arithmetic Element) and the TDS-E DECtape Control will operate only with the
SA600 and SA620 computers.
Moduies
can be inserted in almost any PDP-SI A Omnibus slot. There are, however, some restrictions and these
are summarized in Table 3-2.
Notice that an MS320 module (Bus Loads) is inserted in slot 1 of the SA600 and SA620 computers. This module
must be modified before it can be used in the SA600 and SA620 computers.
If the modification has been accom-
plished, R55 (Figure 3-2) will have been removed;
if R55 is present, carry out the procedure outlined in DEC
ECO MS320-00007.
3-2

Table 3-2
PDP-SfA Computers, Dedicated Omnibus Slots
PDP-8/A Semiconductor,
Omnibus Slot SA600 SA600 +KES-E SA620 SA620 +KES-E SA400, SA420,
SASOO, SAS20
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
IS
19
20
NOTES:
I M8320
M8316
M8317
I I
I
M8300 I
M8310
M8330
M8320 I
M8316
M8317
I
M8300
M8310
M8341
M8340 I
M8330
I
M8320
M8316
M8317
MS300
MS310
MS330
M8320
M8316
M8317
MS300
MS310
MS341
MS340
MS330
I
I
I
I
1. MS316 and MS317 are interchangeable in slots 2 and 3.
2. Module numbers are related
to options as follows:
MS315
MS316
MS317
MS320
MS300 }
MS310
MS330
CPU (KKS-A)
I/O Option Board (DKCS-AA)
Extended Option Board (KMS-A)
Bus Loads I
CPU
KKS-E Timing Generator
KKS-E
08 -1785
Figure 3-2 Part of M8320 Module Showing R55,
Which is Removed for 8A Operation
3-3
M8315
M8316
M8317

3.2 CHASSIS DESCRIPTIONS
Three chassis types are available. The PDP-8/ A semiconductor computer chassis is illustrated in Figure 3-3. (The
front panels have been removed.) Modules are inserted in the Omnibus from the front
of the unit. Both quad-and
hex-size modules can be inserted;
the fingers on connectors E and F of the hex size modules do not carry
Omnibus signals. (Some hex modules
do not have connectors E and F.) Figure 3-4 illustrates the dimensions of
the same computer, as well as indicating the ac line and fuse locations.
G8016
REGULATOR
ASSEMBLY
POWER
CONTROL
FUSE
MASTER-SLAVE
SWITCH
Figure 3-3 PDP-8/A Semiconductor Chassis
3-4
LIMITED FUNCTION
PANEL
7.2884

NOTE: This circuit breaker controls dc power
applied
to the OMNIBUS. It does not remove
ac power from the power transformer or fans.
If you are servicing the power supply, you are
advised
to:
1. Turn PDP-8/A off.
2. Unplug the power cord.
3. Remove metal jewelry that could short
the battery, heat up, and
cause burns.
'\9 in. l48. 26cm)
Figure 3-4 PDP-8fA Semiconductor Computer Chassis Dimensions
3-5
4A(110V
OPERATION) OR 2A
(220V OPERATION)
SLOW BLOW FUSE
08-1146