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