HP Cisco MDS 9020 - Fabric Switch User manual

HP 9000 Series 500 Computers
Model
520
HP 9020 ServiceManual
Flin- HEWLETT
a:~ PACKARD

HP 9020 Service Manual
for the HP 9000 Series 500
Model520 Computer
Manual Part No. 09020-90037
This service manual is part of the HP 9000 Model 520 Service Documentation Package, part
number 09020-80038.
© Copyright 1984, 1985, Hewlett-Packard Company.
This documentcontains proprietary information which
is protected bycopyright. All rights are reserved. No part ofthis
document may be photocopied, reproduced or translated to another language without the prior written consent of
Hewlett-Packard Company. The information contained
in this document is subject to change without notice.
Restricted Rights Legend
Use, duplication, or disclosure by the Government is subject to restrictions as set forth
in paragraph (b)(3)(8) of the
Rights in Technical Data and Software clause
in DAR 7-104.9(a).
Hewlett-Packard Company
3404 East Harmony Road, Fort Collins, Colorado 80525

ii
Printing History
New editions of this manual will incorporate all material updated since the previous edition. Update
packages may
be issued between editions and contain replacement and additional pages to be
merged into the manual by the user. Each updated page will be indicated by a revision date at the
bottom ofthe page. Avertical bar
in the margin indicates the changes on each page. Note that pages
which are rearranged due to changes on a previous page are not considered revised.
The manual printing date
and part number indicate its current edition. The printing date changes
when a new edition
is printed. (Minor corrections and updates which are incorporated at reprint do
not cause the date to change.) The manual part number changes when extensive technical changes
are incorporated.
This manual obsoletes part number 09020-90038. This manual differs from the obsoleted manual
in that this manual contains updated and expanded replaceable parts lists, and numerous technical
and editorial updates.
September
1984 ...First Edition
January 1985...Update
February 1985...First Edition with update merged
Warranty Statement
Hewlett-Packard products are warranted against defects in materials and workmanship. For Hewlett-Packard computersys-
tem products sold
in the U.S.A. and Canada, this warranty applies for ninety (90) days from the date of shipment.* Hewlett-
Packard will, at its option, repairor replace equipmentwhich provesto be defective during the warranty period. This warranty
includes labor, parts, and surface travel costs, if any. Equipment returned to Hewlett-Packard for repair must be shipped
freight prepaid. Repairs necessitated by misuse of the equipment, or by hardware, software, or interfacing not provided by
Hewlett-Packard are not covered by this warranty.
HP warrants that its software and firmware designated by HP for use with a CPU will execute its programming instructions
when properly installed on that CPU.
HP does not warrant that the operation of the CPU, software, or firmware will be uninter-
rupted or error free.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. HEWLETT-PACKARD SHALL NOT
BE LIABLE FOR
CONSEQUENTIAL DAMAGES.
• For other countries, contact your local Sales and Support Office to determine warranty terms.
09020-90037. rev 1/85

Table of Contents
Chapter 1. General Information
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-2
Warnings, Cautions,
and Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-3
Repair Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-4
Ac ComponentsNoltage Conversion ............................................. 1-4
Safety
....................................................................... 1-5
General Safety Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-5
Safety Guidelines for High-Voltage Testing
.................................... 1-5
Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-6
Printer Paper Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-6
Flexible Disc Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-7
Computer Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-8
Case
.................................................................... 1-8
Air Intake Grill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-8
9130K Flexible Disc Drive Cleaning .............................................. 1-8
Chapter 2. Theory of Operation
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-1
Power Supply Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-4
Ac Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-6
Primary Board ............................................................ 2-6
Secondary Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-6
Supervisor Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-7
Status LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-8
Power Diagrams ........................................................... 2-8
Processor Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-12
Stack Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-12
Stack Boards
............................................................ 2-14
Stack Motherboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-14
Clock Board .................... '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-15
Power Interlock Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-15
Cooling
................................................................. 2-15
Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-15
Memory Organization -256K Byte
RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-15
Memory Mapping
........................................................ 2-16
Memory Organization -512K Byte
RAM Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-20
Memory Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-22
Memory Organization - 1 Megabyte
RAM Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-25
Memory Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-26
lOP Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-29
iii

iv
Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-30
lOP Bus Interface
........................................................ 2-31
Miscellaneous Status
and Control ........................................... 2-31
Keyboard
and Input Device Scanning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-32
Beeper
................................................................. 2-33
RTCINVM Logic and Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-33
Power-Up/Power-Down Sense Circuitry
...................................... 2-33
Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-34
98770A and 98780A Display Interface Module (DIM) .......................... 2-34
98760A Standard Color Graphics Display .................................... 2-37
Thermal Printer
............................................................. 2-41
Logic Board
............................................................. 2-41
Motor Drive Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-44
Paper Sensor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-45
Printhead Interconnect Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-45
Printer Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-45
Mass Storage
.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-46
9130K Flexible Disc Drive Controller Card ................................... 2-47
Winchester Fixed
Disc Drive liD Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-48
Motherboard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-50
Power Supply ............................................................ 2-50
Processor Stack ........................................................ " 2-50
Fans .................................................................... 2-50
Mass Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-50
liD Backplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-50
Printer and Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-51
liD Backplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-51
Display
................................................................. 2-51
liD Bus
................................................................. 2-51
Mass Storage Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-51
Bootstrap Loader Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-52
Boot Loader
ROM .............. , ......................................... 2-52
Reserved Bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-53
liD Door Interlock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-53
Chapter 3: Testing and Troubleshooting
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1
Troubleshooting
and Repair Strategy ............................................ , 3-1
HP-CIO .................................................................. 3-1
Repair
................................................................... 3-3
Problem Isolation
............................................................ , 3-3
Self-Tests
and Diagnostics Overview ............................................ , 3-4
Module Self-Tests ........................................................ , 3-4
Self-Test Supervisory Code ................................................ , 3-4
System Functional Tests ................................................... , 3-4
()<)()20-90037, rev 1185

Module Self-Tests ............................................................. 3-5
Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-5
Processor Stack .......................................................... , 3-5
Printer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-7
Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-7
Display Interface Module
(DIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-7
98760A Standard Color Graphics Display .................................... , 3-7
98770A High Performance Color Graphics Display ............................. 3-7
98780A Monochromatic Display ............................................ , 3-8
9130K Flexible Disc Drive/Controller Card ..................................... 3-8
Winchester Fixed
Disc Drive/Controller Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-8
Bootstrap Loader Card
.................................................... , 3-8
Self-Test Supervisory
Code .................................................... , 3-9
Internal I/O Bus
.......................................................... , 3-9
Memory
................................................................. , 3-9
Printer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-10
Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-10
Display Interface Module (DIM) ............................................. 3-10
98760A Display Alpha and GraphicS' ........................................ 3-10
9130K Flexible Disc Drive/Controller Card ................................... 3-10
Winchester Fixed Disc Drive/Controller Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-10
System Functional Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-11
98760A Display Color Alignment. .............................................. 3-12
Overview of thE~ Alignment Process .......................................... 3-12
When Needed
.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-12
Required Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-12
Test Conditions
.......................................................... 3-12
How
It Works. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-13
The Intensity Adjustment Procedure
....................................... " 3-13
Early Warning/Fault Tolerance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-15
Overtemperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-15
Memory Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-15
Real-Time Clock/Non-Volatile Memory (RTC/NVM)
........................... 3-16
()9()20-90037. rev: 1;85
v

vi
Chapter 4. Assembly Access
Introduction .................................................................. 4-1
General Safety Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-2
Electrostatic Discharge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-2
Case Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-4
Side Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-4
Front Cover, including Keyboard Bezel
....................................... 4-6
Rear Cover, including Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-9
Replaceable Assemblies
...................................................... , 4-12
liD Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-12
9130K Flexible Disc Drive Controller Card ................................... 4-13
Winchester Fixed
Disc Drive Controller Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-15
Bootstrap Loader
Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-18
Processor Stack. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-18
Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-27
Display Interface Module (98770A or 98780A Displays)
........................ 4-28
Display AlphalInterface Board (98760A Display)
.............................. 4-30
Display Lid .............................................................. 4-31
Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-32
Printer .................................................................. 4-36
9130K Flexible Disc Drive ................................................. 4-47
Winchester Fixed
Disc Drive ................................................ 4-51
Power Supply Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-54
Power Cord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-57
Ac Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-59
Line Filter
............................................................... 4-61
Power Switch Assemblyl Ac Module Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-64
Processor Stack Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-65
Power Supply Fan ........................................................ 4-66
liD Card Cage Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-67
liD Backplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-70
Motherboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-72
HP 98760A Standard Color Graphics Display ............................ '" .. 4-74
Chapter 5. Replaceable Parts
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-1
Exchange Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-2
Non-Exchange Parts
.......................................................... 5-3
Product Support Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-3

Extender Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-4
Documentation ............................................................. " 5-4
Printer Paper. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-5
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-6
Covers
........................................ , .......................... 5-7
Chassis Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-8
Printer ...... , ........................................................... , 5-11
Processor Stack ......................................................... , 5-13
I/O Cage .... , ........................................................... , 5-15
AC Module .. ,. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-16
Winchester Fixed
Disc Drive ............................................... , 5-17
Flexible
Disc Drive ................... , ................................... , 5-18
Keyboard
... , .......................................................... , 5-19
98760 Display .......................................................... , 5-20
Keyboard Configurations .................................................... , 5-22
Appendix A. Technical Data
Appendix B. Installation and Test (09020-90012)
Appendix C. Error Messages
Appendix D. Motherboard Pinout
Data
Appendix E. I/O Backplane Pinout Data
Appendix F. Option Installation Notes
Appendix G. Sales and Support Offices (5955-6587)
Appendix
H. Site Preparation (09000-90040)
Appendix I. 98770A Service Manual (98770-90031)
Appendix J. 98780A Service Manual (98780-90030)
09020-90037, rev: 1185
vii

viii
Figures
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
2-16
2-17
2-18
2-19
2-20
2-21
2-22
2-23
2-24
2-25
2-26
3-1
3-2
3-3
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
Computer Block Diagram
............................................... " 2-2
Computer Interconnection Diagram
...................................... " 2-3
Power Supply Assembly Block Diagram ................................... " 2-5
Power Distribution Diagram ............................................. " 2-9
Voltage Sensing Diagram
................................................ 2-10
Safety Grounding Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-11
Processor Stack Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-13
256K
RAM Finstrate Block Diagram ....................................... 2-16
256K Memory Mapping Organization
...................................... 2-17
256K Memory Mapping Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-18
256K Memory Healing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-20
512K
RAM Board Block Diagram ......................................... 2-21
512K Memory Mapping Organization
...................................... 2-22
512K Memory Mapping Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-23
512K Memory Healing
.................................................. 2-24
1 Megabyte Memory Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-25
1 Megabyte Memory Mapping Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-26
1 Megabyte Memory Healing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-28
Keyboard Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-31
Display Interface Module
(DIM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-35
Alpha/Interface Board Block Diagram
..................................... 2-38
Graphics/Digital Video Board Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-39
Printer Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-42
Flexible
Disc Drive Controller Card Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . .. 2-47
Winchester Fixed
Disc Drive I/O Card Block Diagram . . . . . . . . . . . . . . . . . . . . . . .. 2-49
Bootstrap Loader Card Block Diagram
.................................... 2-53
Power-up Sequence ................................................... " 3-2
Video Board Pots
and Test Points ......................................... 3-13
Sweep Board Adjustments ............................................... 3-14
Side Doors ........................................................... " 4-4
Opening Side Door .................................................... " 4-5
Removing Side Door
..................................................... 4-6
Removing Keyboard Bezel
.............................................. " 4-7
Releasing Front Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-8
Removing Front Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-9
Unlatching Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-10
Lifting Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-11
Removing Rear Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-11
Opening I/O Door ...................................................... 4-12
Disconnecting I/O Cable
................................................. 4-12
Removing Mass Storage Cover
........................................... 4-13
Removing Flexible
Disc Drive Controller Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-14
Removing Fixed Disc Drive Controller Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-15
Disassembling Fixed
Disc Drive Controller Assembly, View 1 .................. 4-16
Disassembling Fixed
Disc Drive Controller Assembly, View 2 .................. 4-17
Removing Upper Board, View 1
.......................................... 4-18
Removing Upper Board, View 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-19

4-19 Removing Trim Piece ................................................... 4-20
4-20 Removing Processor Stack Door. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-21
4-21 Disconnecting lOP Cables
............................................... 4-22
4-22 Removing Processor Stack Clock Board
................................... 4-24
4-23 Removing Processor Stack Cover Plate
.................................... 4-25
4-24 Disconnecting Processor Stack Fan Cable
.................................. 4-26
4-25 Removing Processor Stack
............................................... 4-26
4-26 Removing Casting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-28
4-27 Removing
DIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-29
4-28 Removing Alpha/Interface Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-30
4-29 Removing Lid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-31
4-30 Releasing Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-32
4-31 Removing Keyboard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-33
4-32 Removing Keycap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-34
4-33 Disassembling Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-35
4-34 Releasing Printer
....................................................... 4-37
4-35 Removing Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-37
4-36 Disassembling Printer
................................................... 4-38
4-37 Removing Transparent Cover
............................................ 4-38
4-38 Releasing Head Load Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-39
4-39 Removing Head Load Bar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-39
4-40 Removing Printhead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-40
4-41 Removing Heat Sinks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-41
4-42 Removing Head Backing Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-42
4-43 Removing Chip Carrier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-43
4-44 Removing Printhead Interconnect Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-43
4-45 Disconnecting Cables from
Logic and Motor Drive Boards . . . . . . . . . . . . . . . . . . .. 4-44
4-46 Removing Logic and Motor
Drive Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-45
4-47 Separating Logic and Motor
Drive Boards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-45
4-48 Removing Paper Sensor Board and Switches Assembly . . . . . . . . . . . . . . . . . . . .
.. 4-46
4-49 Releasing Flexible
Disc Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-47
4-50 Removing Flexible Disc Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-48
4-51 Disassembling Flexible
Disc Drive, View 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-49
4-52 Disassembling Flexible
Disc Drive, View 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-50
4-53 Releasing Fixed Disc Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-51
4-54 Removing Fixed
Disc Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-52
4-55 Disassembling Fixed
Disc Drive, View 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-53
4-56 Disassembling Fixed
Disc Drive, View 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-53
4-57 Discharging Power Supply Assembly
...................................... 4-55
4-58 Releasing Power Supply Assembly
........................................ 4-56
4-59 Removing Power Supply Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-57
4-60 Removing Ac Power Cord. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-58
4-61 Releasing
Ac Module ................................................... 4-59
4-62 Removing
Ac Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-60
4-63 Removing Display Connector Assembly .................................... 4-61
4-64 Removing
Ac Module Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-62
4-65 Disconnecting Line
Filter Wires. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-63
4-66 Removing Line Filter
.................................................... 4-63
4-67 Removing Power Switch Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-64
ix

x
4-68 Removing Processor Stack Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-65
4-69 Disconnecting Power Supply Fan Cable
................................... 4-66
4-70 Removing Power Supply Fan .......................................... " 4-66
4-71 Removing Rear Card Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-68
4-72 Disconnecting
I/O Card Cage Fan Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-68
4-73 Removing
I/O Card Cage Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-69
4-74 Removing Front Card Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-70
4-75 Removing I/O Backplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-71
4-76 Removing
"H" Casting ................................................. 4-72
4-77 Removing Motherboard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-73
4-78 Removing Top Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-75
4-79 Removing Top
Lid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-76
4-80 Releasing Display Power Supply Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-77
4-81 Removing Display Power Supply Board
................................... 4-78
4-82 Releasing Sweep Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-79
4-83 Removing Sweep Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-80
4-84 Anode Orientation ...................................................... 4-81
4-85 Removing Display Motherboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-82
4-86 Removing
RFI Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-83
4-87 Opening Cage Door
.................................................... 4-83
4-88 Removing Graphics/Digital Video Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-84
4-89 Removing Video Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-85
4-90 Removing Front Bezel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-87
4-91 Removing CRTNoke Assembly
.......................................... 4-87
4-92 Preparing Degaussing Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-88
4-93 Placement of Degaussing Cable on
CRT Noke Assembly . . . . . . . . . . . . . . . . . . . .. 4-89
4-94 Yoke Support Plate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-89
4-95 Replacing Front Bezel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-90
4-96 Removing Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-91
5-1 Covers Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-6
5-2 Chassis Components Exploded
View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-9
5-3 Printer Exploded
View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-10
5-4 Printhead Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-10
5-5 Processor Stack Exploded View .......................................... 5-12
5-6
I/O Cage Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-14
5-7
AC Model Exploded View ............................................... 5-16
5-8 Winchester Fixed
Disc Drive Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-17
5-9 Flexible
Disc Drive Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-18
5-10 Keyboard Exploded View ................................................ 5-19
5-12
ASCII Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-23
5-13 French Keyboard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-23
5-14 Spanish Keyboard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-23
5-15 German Keyboard
..................................................... 5-24
5-16 Katakana Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-24
5-17 Swedish/Finnish Keyboard
............................................... 5-24
D-1 Motherboard Connectors Locator Drawing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. D-2
E-1 I/O Backplane Connectors Locator Drawing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. E-2

Tables
1-1
4-1
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5-13
5-14
5-15
5-16
C-l
D-l
D-2
E-l
E-2
Computer Service Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-2
Keyboard Language Resistor Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-36
Exchange Parts
......................................................... 5-2
Non-Exchange Parts
..................................................... 5-3
Product Support Tools ............ ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-3
Extender Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-4
Product Support Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-4
HP Printer Replacement Paper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-5
Covers Parts
List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-7
Chassis Components Parts
List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-8
Printer Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-11
Processor Stack Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-13
liD Cage Parts List ..................................................... 5-15
AC Module Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-16
Winchester Fixed
Disc Drive Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-17
Flexible
Disc Drive Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-18
Keyboard Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-19
98760 Display Parts List. ................................................ 5-20
Self Test Error 1 Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C-4
Motherboard Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. D-l
Motherboard Signal Definitions ............................................ D-4
liD Backplane Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. E-l
liD Backplane Signal Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. E-5
xi

xii

Table of Contents
Chapter 1. General Information
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-2
Warnings, Cautions,
and Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-3
Repair Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-4
Ac ComponentsN oltage Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-4
Safety
....................................................................... 1-5
General Safety Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-5
Safety Guidelines for High-Voltage Testing
.................................... 1-5
Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-6
Printer Paper Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-6
Aexible
Disc Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-7
Computer Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-8
Case
................ , .......... " .... , ............... , ................ ,. 1-8
Air Intake Grill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-8
9130K Aexible Disc Drive Cleaning .............................................. 1-8

General Information
Introduction
Note
Hewlett-Packard assumes no responsibility for customer repairs
or
modifications.
Chapter
1
This manual contains servicing information for the Hewlett-Packard (HP) 9000 Model 520
Computer (hereinafter referred to as the computer). HP supports repairing the computer to the
assembly level, that
is, isolating the problem to the replaceable assembly. Then the defective
assembly
is exchanged for a new or rebuilt assembly.
This chapter contains general information about the computer and
its servicing.
Additional information
in this manual includes:
• Theory of Operation
• Troubleshooting Procedures
• Assembly Access Procedures
• Replaceable Parts
• Data
Sheet (Specifications and Options)
• Installation
and Test
• Error Messages
• Motherboard and liD Backplane Pinout Data
• Option Installation Notes
• Sales and Support Offices
Note that the computer specifications and options are contained in Appendix A. Also, installation
information
is not contained in this chapter but is found in Appendix B.
Detailed servicing information is not provided for the following assemblies: 98770A Color Graphics
Display, 98780A Monochromatic Display, and 9130K Flexible
Disc Drive. To service one of these
assemblies, refer to the appropriate manual listed
in Table 1-1.
1-1

1-2 General Information
Table 1-1. Computer Service Documentation
Manual Title Part Number
98770A Color Graphics Display Service Manual 98770-90031
98780A Monochromatic Display Service Manual 98780-90030
9130K Flexible
Disc Drive Service Manual 09130-90030
Note
If you are unfamiliar with the computer, read the Installation and Test
Manual contained
in Appendix B of this manual.
Description
The computer is a 32-bitsystem with integral processor stack, power supply, ac module, keyboard,
display, printer, mass memory, and input/output
(I/O) backplane. The printer and mass memory
are optional assemblies.
The computer has
one of two operating systems: BASIC or UNIX. Both systems are random-access
memory
(RAM) based and loaded from disc.
The computer processor consists of an NMOS-III based processor stack that, at a minimum,
contains a central processor unit (CPU), an
I/O processor (lOP), and memory assemblies. The
CPU, lOP, and memory boards reside in the stack and communicate via the common memory
processor bus
(MPB).
The boards may be finstrates or polystrates. Finstrates are copper cored boards with the NMOS
chips bonded to them. They provide the combined functions of cooling fins and ceramic substrates.
Cooling air
is drawn through the stack between the boards to dissipate heat from the chips. The
boards are accessible from the left side of the computer.
Polystrates (from polyimide and finstrate) are polyimide boards without the copper core. However,
copper heat sinks are mounted on the circuit side of the boards, to dissipate heat from the chips.
The CPU chip
is a microprogrammed 32-bit processor. The lOP chip interfaces to the system I/O
bus. Each lOP supports eight select codes. Up to three lOPs can be included in the computer. The
RAM chips are addressed by a memory controller chip that corrects all single-bit errors. Memory
can
be made up of 256K, 512K, or 1 Megabyte RAM memory boards (1M byte RAM boards must
be used in pairs).
The mainframe includes the motherboard,
I/O backplane, interconnecting cables, power supply,
and three cooling fans. The top covers, side covers, and keyboard bezel are also part of the basic
computer.

General Information 1-3
The thermal printer is an optional module. Other hardware options include displays and mass
storage devices.
One of three displays can be selected, and flexible disc and fixed disc storage
devices are available. Various combinations of CPU, lOP, and
RAM memory boards can configure
the processor stack. Also, several types of HP-IO cards are available for various interfacing require-
ments. Refer to Appendix A for additional information on options.
The HP-IO cards and mass storage controller cards are accessible from the right side of the
computer, and the processor stack cards from the left side. The computer rests on three rubber feet
at the front and two platen-like rollers at the rear. Thus,
it can easily be moved for service
accessibility by lifting slightly at the front and rolling forward or backward.
CAUTION
THE WINCHESTER FIXED DISC DRIVE CAN BE DAMAGED WHEN
SUBJECTED TO A SHOCK OF lOG OPERATING OR 20G NON-
OPERATING. TO PREVENT DAMAGE, LOWER COMPUTER GENT-
L
Y AFTER MOVING IT ON ITS ROLLERS.
Three dc box fans provide cooling for the computer. The fans draw the air through a grill under the
keyboard
and exhaust the air out the back of the computer. One fan is integral to the processor
stack. The other fans are mounted to the chassis,
one in the power supply area and one in the I/O
card cage area. The 1/0 card cage fan operates at constant speed. The other two fans are variable,
increasing
in speed as the temperature increases. The computer shuts down if the temperature rises
to 100°C
in the stack or to 97°C in the power supply.
Warnings, Cautions, and Notes
Warnings, cautions, and notes are used throughout this manual. Warnings call attention to potential
hazards for personnel. Cautions call attention to potential hazards for equipment. Notes emphasize
important information or instructions.
Although
all warnings, cautions, and notes are important, one warning and one caution are in-
cluded here to acquaint you with computer considerations.
WARNING
DISCHARGE POWER SUPPLY CAPACITORS USING POWER
SUPPLY DISCHARGE TOOL, PART NUMBER 09855-67004, BE-
FORE REMOVING POWER SUPPLY FROM COMPUTER. FAILURE
TO FOLLOW THIS PROCEDURE COULD RESULT IN EXPOSURE
TO LETHAL SHOCK HAZARD.
CAUTION
TO PREVENT DAMAGE DUE TO ELECTROSTATIC DISCHARGE
(ESD), FOLLOW THE PROCEDURES PROVIDED IN CHAPTER
4.

1-4 General Information
Repair Philosophy
The computer repair philosophy consists of early warning of probable failures, three overlapping
levels of diagnostics, service utilities,
and most assembly replacement within 15 minutes.
The computer
is repaired at an assembly replacement level. Parts that are most commonly replaced
are exchange parts
and are on the Computer Support Division (CSD) exchange program. When an
exchange part fails, it should be returned to CSD for repair, and a rebuilt part should be obtained. If
a new part is purchased instead, it is unnecessary to return the failed part. Chapter5 contains lists of
all replaceable parts. Tables in Chapter 5 also list exchange parts with new and rebuilt part
numbers.
In addition to the standard three levels of Field Service Inventory (FSI) sets, several other sets are
available depending
on the selected options. These are as follows:
• GP-IO liD Card FSI
• HP-IB I/O Card FSI
• ASI I/O Card FSI
• PSI I/O Card FSI
• MUX liD Card FSI
• LAN liD Card FSI
• 98760A Standard Color Graphics Display FSI
• 98770A High Performance Color Graphics Display FSI
• 98780A Monochromatic Display FSI
• 9130K Flexible Disc Drive FSI
Ac ComponentsNoltage Conversion
WARNING
IF IT IS NECESSARY TO REPlACE THE POWER CORD, THE RE-
PlACEMENT CORD MUST HAVE THE SAME POlARITY AS THE
ORIGINAL CORD. OTHERWISE, ASHOCK HAZARD MIGHT EXIST
WHICH COULD RESULT IN INJURY OR DEATH. ALSO, THE
EQUIPMENT COULD BE SEVERELY DAMAGED IF EVEN A RE-
lATIVELY MINOR INTERNAL FAILURE OCCURRED.
The ac module has an attached 6-foot power cord that plugs into an ac outlet to provide primary
power to the computer. Besides the power cord, the ac module contains a line
filter, ac module
cable,
and the on/off power switch/circuit breaker.
The computer
is wired for either 110V or 220V and can be converted from one to the other in the
field. Conversion requires changing the power cord, ac module cable, and power switch. Chapter4
provides procedures for replacing
all ac components.