IBM ThinkPad 380 Owner's manual

Thank you for purchasing this Factory Service
Manual CD/DVD from servicemanuals4u.com.
Please check out our eBay auctions for more great
deals on Factory Service Manuals:
servicemanuals4u

This Manual Supports:
ThinkPad 380 (2635)
ThinkPad 385 (2635)
ThinkPad 560
ThinkPad 560E (2640) (2640)
ThinkPad 760C/CD (9546)
ThinkPad 760E/ED (9546)
ThinkPad 760L/LD (9546)
ThinkPad 760EL/ELD (9547)
ThinkPad 760XL (9546)
ThinkPad 760XD
ThinkPad 765D
ThinkPad 765L
ThinkPad 770
SelectaDock III
(9547)
(9546)
(9547)
(9548, 9549)
(3547)
S05L-1270-01
IBM Mobile Systems
Hardware Maintenance Manual
Volume 4: ThinkPad Computers
September 1997
We Want Your Comments!
(Please see page 697)

S05L-1270-01
IBM Mobile Systems
Hardware Maintenance Manual
Volume 4: ThinkPad Computers
September 1997
We Want Your Comments!
(Please see page 697)
IBM

Note
Before using this information and the product it
supports, be sure to read the general information
under “Notices” on page 702.
Second Edition (September 1997)
The following paragraph does not apply to the United
Kingdom or any country where such provisions are
inconsistent with local law: INTERNATIONAL
BUSINESS MACHINES CORPORATION PROVIDES THIS
PUBLICATION “AS IS” WITHOUT WARRANTY OF ANY
KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT
NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. Some states do not allow disclaimer of
express or implied warranties in certain transactions,
therefore, this statement may not apply to you.
This publication could include technical inaccuracies or
typographical errors. Changes are periodically made to
the information herein; these changes will be incorporated
in new editions of the publication. IBM may make
improvements and/or changes in the product(s) and/or the
program(s) described in this publication at any time.
This publication was developed for products and services
offered in the United States of America. IBM may not offer
the products, services, or features discussed in this
document in other countries, and the information is subject
to change without notice. Consult your local IBM
representative for information on the products, services,
and features available in your area.
Requests for technical information about IBM products
should be made to your IBM reseller or IBM marketing
representative.
 Copyright International Business Machines
Corporation 1997. All rights reserved.
Note to U.S. Government users–Documentation related to
Restricted rights–Use, duplication, or disclosure is subject
to restrictions set forth in GSA ADP Schedule Contract
with IBM Corp.
ii IBM Mobile Systems HMM

About This Manual
This manual contains service and reference information for
IBM ThinkPad 380, 385, 560, 760, 765, 770, and
SelectaDock III products. Use this manual along with the
advanced diagnostic tests to troubleshoot problems
effectively.
The manual is divided into sections as follows:
The Introduction section provides general information,
guidelines, and safety information required to service
computers.
The product-specific sections include service,
reference, and product-specific parts information.
The Common Devices Checkout section provides
procedures for testing the devices that are commonly
attached to ThinkPad computers.
The Miscellaneous Information section contains
information about acronyms, abbreviations, terms,
and a telephone number listing.
Important
This manual is intended for trained servicers who are
familiar with ThinkPad products. Use this manual
along with the advanced diagnostic tests to
troubleshoot problems effectively.
Before servicing an IBM mobile product, be sure to
review the safety information under “Safety Notices
(Multi-lingual Translations)” on page 8 and “Safety
Information” on page 15.
iii

Related Publications
The following mobile product publications are available
through IBM or your IBM Authorized Dealer.
Publication Part, Form Number
Mobile Systems HMM
Volume 1: Laptop,
Notebook, Portable, and
ThinkPad Computers
(Models L40, CL57, N45,
N51, P70, P75, ThinkPad
300, 350, 500, 510, 710T,
Expansion Unit, Dock I,
Dock II)
30H2356, S82G-1501-01
Mobile Systems HMM
Volume 2: ThinkPad
Computers
(Model 340, 355, 360, 370,
700, 701, 720, 750, 755)
30H2357, S82G-1502-03
Mobile Systems HMM
Volume 3: ThinkPad
Computers
(Model 365, 380, 385, 560,
760, SelecataDock
84H8099, S82G-1503-05
ThinkPad 700 (9552) HMS 42G2016, S42G-2016
ThinkPad 700 (9552) HMR 42G2015, S42G-2015
ThinkPad 700C (9552) HMS 42G2022, S42G-2022
ThinkPad 700C (9552) HMR 42G2021, S42G-2021
ThinkPad 720/720C (9552)
HMS 61G1193, S61G-1193
ThinkPad 720/720C (9552)
HMR 61G1187, S61G-1187
ThinkPad 730T (2524) HMM 82G5497, S82G-5497
ThinkPad Exp. Crtg. (3550)
HMS 42G2338, S42G-2338
ThinkPad Exp. Crtg. (3550)
HMR 42G2339, S42G-2339
PS/2 FaxConcentrator HMS 15F2262, S15F-2262
PS/2 FaxConcentrator HMR 84F8541, S84F-8541
PS/2 Comm. Cartridge I
HMS 10G5993, S10G-5993
PS/2 Comm. Cartridge I
HMR 10G5992, S10G-5992
IBM High Speed Internal,
PCMCIA Data/Fax Modems 61G1556, S61G-1556
iv IBM Mobile Systems HMM

Related Diskettes
The following diskettes are available through IBM or your
IBM Authorized Dealer.
Diskette Part, Form Number
ThinkPad 300 (2615)
Advanced Diagnostics
Diskette
33G9361, S33G-9361
ThinkPad 350, 350C, 425,
425C (2618) Advanced
Diagnostics Diskette
A211000, GA21-1000
ThinkPad 365 (2625)
Advanced Diagnostics
Diskette
76H7578, S30H-2498
ThinkPad 380, 385 (2635)
Maintenance Diskette 06J0333, S06J-0333
ThinkPad 500 (2603)
Advanced Diagnostics
Diskette
71G3702, S71G-3702
ThinkPad 510 (2604)
Advanced Diagnostics
Diskette
83G8095, S83G-8095
ThinkPad 700 (9552)
Reference Diskette 42G2017, S42G-2017
ThinkPad 700C (9552)
Reference Diskette 42G2023, S42G-2023
ThinkPad 720/720C (9552)
Reference Diskette 61G1194, S61G-1194
ThinkPad Hardware
Maintenance Diskette
(for all Models 355, 360,
560, 750, 755, 760)
78H5384, S78H-5384
ThinkPad Dock I (3545) 71G4140, S71G-4140
Docking Station (3550) 42G2428, S42G-2428
Data/Fax Modem 61G1556, S61G-1556
FaxConcentrator/A 84F8540, S84F-8540
v

vi IBM Mobile Systems HMM

Contents
Introduction . . . . . . . . . . . . . . . . . . . 1
Mobile Computer Descriptions ........... 2
Drive and Diskette Compatibility Matrix ....... 5
Important Service Information ........... 6
Safety Notices (Multi-lingual Translations) ..... 8
Safety Information . . . . . . . . . . . . . . . . 15
Laser Compliance Statement ........... 20
ThinkPad 380, 385 (2635) ............ 23
Read This First .................. 25
Checkout Guide . . . . . . . . . . . . . . . . . 29
Symptom-to-FRU Index . . . . . . . . . . . . . . 40
Related Service Procedures ............ 52
Product Overview (380, 385) . . . . . . . . . . . 57
FRU Removals and Replacements ......... 58
Locations . . . . . . . . . . . . . . . . . . . . 101
Parts Listing 380, 385 (2635) .......... 104
Common/Option Parts List ............ 115
ThinkPad 560, 560E (2640) .......... 121
Read This First ................. 123
Checkout Guide . . . . . . . . . . . . . . . . 127
Symptom-to-FRU Index . . . . . . . . . . . . . 138
Related Service Procedures ........... 150
Product Overview (560, 560E) . . . . . . . . . 154
FRU Removals and Replacements ........ 156
Locations . . . . . . . . . . . . . . . . . . . . 183
Parts Listing 560, 560E (2640) ......... 186
Common and Option Parts List ......... 193
ThinkPad 760 (9546, 9547) . . . . . . . . . . 199
Read This First ................. 202
Checkout Guide . . . . . . . . . . . . . . . . 205
Symptom-to-FRU Index . . . . . . . . . . . . . 223
Related Service Procedures ........... 236
Product Overview (760) . . . . . . . . . . . . . 241
FRU Removals and Replacements ........ 246
LCD Removal and Replacement ......... 290
LCD Unit, 12.1 SVGA (P/N 29H9226, ASM P/N
29H9029) . . . . . . . . . . . . . . . . . . . 291
LCD Unit, 12.1 SVGA (P/N 29H9226, ASM P/N
73H6599) . . . . . . . . . . . . . . . . . . . 296
LCD Unit, 10.4 SVGA (P/N 29H9227) ...... 302
LCD Unit, 10.4 VGA (P/N 46H5355) ....... 307
LCD Unit, 11.3 DSTN (P/N 39H6232) ...... 312
LCD Unit, 12.1 XGA .............. 317
LCD Unit, 12.1 SVGA (P/N 82H8496) ...... 323
LCD Unit, 12.1 SVGA (P/N 11J8867, ASM P/N
11J8855) . . . . . . . . . . . . . . . . . . . 329
LCD Unit, 12.1 SVGA (P/N 46H5725, ASM P/N
46H5723) . . . . . . . . . . . . . . . . . . . 335
 Copyright IBM Corp. 1997 vii

Locations . . . . . . . . . . . . . . . . . . . . 341
Parts Listing 760 (9546, 9547) ......... 346
LCD Parts List ................. 382
Common or Option Parts List .......... 402
ThinkPad 765D (9546), 765L (9547) ....... 409
Read This First ................. 411
Checkout Guide . . . . . . . . . . . . . . . . 415
Symptom-to-FRU Index . . . . . . . . . . . . . 432
Related Service Procedures ........... 448
Product Overview (765D, 765L) . . . . . . . . . 453
FRU Removals and Replacements ........ 454
Locations . . . . . . . . . . . . . . . . . . . . 503
Parts Listing 765D (9546), 765L (9547) ...... 506
Common and Option Parts List ......... 514
ThinkPad 770 (9548, 9549) . . . . . . . . . . 521
Read This First ................. 523
Checkout Guide . . . . . . . . . . . . . . . . 528
Power Management Features .......... 540
Symptom-to-FRU Index . . . . . . . . . . . . . 542
Undetermined Problems . . . . . . . . . . . . . 561
Related Service Procedures ........... 562
Product Overview (770) ............. 567
FRU Removals and Replacements ........ 568
Locations . . . . . . . . . . . . . . . . . . . . 607
Parts Listing 770 (9548, 9549) .......... 610
Common and Option Parts List ......... 614
SelectaDock III (3547-003) . . . . . . . . . . . 621
Read This First ................. 622
General Preparation . . . . . . . . . . . . . . . 624
Checkout Guide . . . . . . . . . . . . . . . . 625
How to Run the Diagnostics ........... 632
Symptom-to-FRU Index . . . . . . . . . . . . . 640
Undetermined Problems . . . . . . . . . . . . . 653
Product Overview (3547-003) . . . . . . . . . . 654
FRU Removals and Replacements ........ 656
Locations . . . . . . . . . . . . . . . . . . . . 673
Parts Listing SelectaDock III (3547-003) ..... 677
Common Devices Checkout .......... 681
External Diskette Drive Test ........... 682
External Display Self-Test ............ 682
External Keyboard/Auxiliary Input Device Checkout 683
Fax/Modem Checkout . . . . . . . . . . . . . . 684
Printer Checkout . . . . . . . . . . . . . . . . 686
Port Replicator Checkout ............ 687
TrackPoint Checkout . . . . . . . . . . . . . . 688
TV Tuner . . . . . . . . . . . . . . . . . . . . 689
Miscellaneous Information . . . . . . . . . . . 695
Acronyms, Abbreviations and Terms ....... 695
Send Us Your Comments! ............ 697
viii IBM Mobile Systems HMM

Do You Need Technical References? ...... 698
Problem Determination Tips ........... 699
Phone Numbers, U.S. and Canada ........ 700
Notices . . . . . . . . . . . . . . . . . . . . . 702
Contents ix

xIBM Mobile Systems HMM

Introduction
Mobile Computer Descriptions ........... 2
Drive and Diskette Compatibility Matrix ....... 5
Important Service Information ........... 6
How to Use Error Messages .......... 7
How to Read POST Error Messages ...... 7
Safety Notices (Multi-lingual Translations) ..... 8
Safety Information . . . . . . . . . . . . . . . . 15
General Safety . . . . . . . . . . . . . . . . 15
Electrical Safety . . . . . . . . . . . . . . . . 16
Safety Inspection Guide ............ 17
Handling Electrostatic Discharge-Sensitive Devices 19
Grounding Requirements . . . . . . . . . . . . 19
Laser Compliance Statement ........... 20
 Copyright IBM Corp. 1997 1

Mobile Computer Descriptions
Models N51, CL57, and P70/75 and Thinkpads 700x and
720x are Micro Channel systems. All others are AT/ISA
bus systems.
Model Type Processor Memory Hrd Dsk
Model L40SX 8543-044 386SX-20 2M/18M 60M
Model N45 SL 2614-065 386SL-25 2M/8M 80M
2614-067 386SL-25 2M/8M 120M
Model N51 SLC 8551-025 386SLC-16 2M/10M 80M
Model N51 SX 8551-033 386SX-16 2M/10M 40M
Model CL57 SX 8554-045 386SX-20 2M/16M 80M
Model P70 386 8573-031 80386-16 2M/8M 30M
8573-061 80386-20 2M/8M 60M
8573-121 80386-20 2M/8M 120M
Model P75 486 8573-161 80486-33 8M/16M 160M
8573-401 80486-33 8M/16M 400M
ThinkPad 300 2615-065 386SL-25 4M/12M 80M
2615-067 386SL-25 4M/12M 120M
ThinkPad 340 2610 486SLC2-50/25 4M/12M 125M
ThinkPad 340CSE 2610 486SLC2-50/25 4M/12M 200M
ThinkPad 340CSE 2610 486SLC2-66/33 4M/12M 360M
ThinkPad 345 2610 486DX4-75 4M/20M 360M
ThinkPad 345CS 2610 DX4-75 4M/20M 540M
ThinkPad 350 2618-AOE 486SL-25 4M/20M 85M
2618-JOA 486SL-25 4M/20M 125M
2618-LOA 486SL-25 4M/20M 250M
ThinkPad 350C 2618-NOA 486SL-25 4M/20M 125M
2618-POA 486SL-25 4M/20M 250M
ThinkPad 355 2619 486SX-33 4M/16M 125M
ThinkPad 355C 2619 486SX-33 4M/16M 125M
2619 486SX-33 4M/16M 250M
ThinkPad 355Cs 2619 486SX-33 2M/16M 170M
2619 486SX-33 2M/16M 250M
ThinkPad 360 2620 486SX-33 4M/16M 170M
2620 486SX-33 4M/16M 340M
ThinkPad 360C 2620 486SX-33 4M/16M 170M
2620 486SX-33 4M/16M 340M
ThinkPad 360Cs 2620 486SX-33 4M/16M 170M
2620 486SX-33 4M/16M 340M
ThinkPad 360Ce 2620 486DX2-50/25 4M/16M 170M
2620 486DX2-50/25 4M/16M 340M
2620 486DX2-50/25 4M/16M 540M
ThinkPad 360Cse 2620 486DX2-50/25 4M/16M 170M
2620 486DX2-50/25 4M/16M 340M
2620 486DX2-50/25 4M/16M 540M
ThinkPad 360P 2620 486SX-33 4M/16M 170M
2620 486SX-33 4M/16M 340M
ThinkPad 365C 2625-205 486DX4-75 8M/24M 340M
2625-x05 486DX4-75 8M/24M 540M
ThinkPad 365E 2625 5x86-100/33 8M/24M 540M
ThinkPad 365ED 2625 5x86-100/33 8M/24M 540M
ThinkPad 365X/XD 2625 Pentium-100 8M/24M 540M
2625 Pentium-100 8M/24M 810M
2625 Pentium-100 8M/24M 1.0G
ThinkPad 365X/XD 2625 Pentium-120 8M/24M 540M
2625 Pentium-120 8M/24M 810M
2625 Pentium-120 8M/24M 1.0G
ThinkPad 365X/XD 2625 Pentium-133 8M/40M 810M
2625 Pentium-133 8M/40M 1.0G
2625 Pentium-133 8M/40M 1.3G
ThinkPad 370C 9545 486DX4-75/25 4M/32M 340M
9545 486DX4-75/25 4M/32M 540M
9545 486DX4-75/33 4M/32M 810M
C Color
M Megabyte
P Pen
T Tablet
TPF ThinkPad File
2IBM Mobile Systems HMM

Model Type Processor Memory Hrd Dsk
ThinkPad 380 2635 Pentium-150 16M/48M 1.08G
2635 Pentium-150 16M/48M 1.35G
2635 Pentium-150 16M/48M 2.10G
2635 Pentium MMX-150 16M/48M 2.10G
2635 Pentium MMX-166 16M/48M 2.10G
ThinkPad 385 2635 Pentium-150 16M/48M 1.08G
2635 Pentium-150 16M/48M 1.35G
2635 Pentium-150 16M/48M 2.10G
2635 Pentium MMX-166 16M/48M 2.10G
ThinkPad 500 2603-081 486SLC2-50/25 4M/12M 80M
2603-171 486SLC2-50/25 4M/12M 170M
ThinkPad 560 2630 Pentium-100 8M/40M 540M
2630 Pentium-100 8M/40M 810M
2630 Pentium-100 8M/40M 1.0G
ThinkPad 560 2630 Pentium-120 8M/40M 540M
2630 Pentium-120 8M/40M 810M
2630 Pentium-120 8M/40M 1.0G
ThinkPad 560 2640 Pentium-130 8M/40M 540M
2640 Pentium-130 8M/40M 810M
2640 Pentium-130 8M/40M 1.0G
ThinkPad 560E 2640 Pentium MMX-150 8M/80M 2.1G
2640 Pentium MMX-166 8M/80M 2.1G
2640 Pentium-130 8M/40M 1.0G
ThinkPad 700 9552-300 486SLC-25 4M/16M 80M
9552-301 486SLC-25 4M/16M 120M
ThinkPad 700C 9552-30B 486SLC-25 4M/16M 120M
ThinkPad 701C 2630 486DX2-25/50 4M/32M 360MB
2630 486DX2-25/50 4M/32M 540MB
2630 486DX4-25/75 8M/32M 360MB
2630 486DX4-25/75 8M/32M 540MB
ThinkPad 701Cs 2630 486DX2-25/50 4M/32M 360MB
2630 486DX2-25/50 4M/32M 540MB
2630 486DX4-25/75 8M/32M 360MB
2630 486DX4-25/75 8M/32M 540MB
ThinkPad 710T 2523-09Y 486SLC2-25 4M/12M TPF
2523-302 486SLC2-25 4M/12M 60M
2523-303 486SLC2-25 4M/12M 60M
ThinkPad 720 9552-307 486SLC-25/50 4M/16M 120M
9552-308 486SLC-25/50 4M/16M 160M
ThinkPad 720C 9552-30J 486SLC-25/50 4M/16M 160M
ThinkPad 730T 2524 486SLC2-25 4M/12M 0M
2524 486SLC2-25 4M/12M 60M
ThinkPad 750 9545-006 486SL-33 4M/20M 170M
9545-008 486SL-33 4M/20M 340M
ThinkPad 750C 9545-306 486SL-33 4M/20M 170M
9545-308 486SL-33 4M/20M 340M
ThinkPad 750Ce 9545 P24S-50/25 4M/20M 340M
ThinkPad 750Cs 9545 486SL-33 4M/20M 170M
9545 486SL-33 4M/20M 340M
ThinkPad 750P 9545-40C 486SL-33 4M/20M 170M
9545-40E 486SL-33 4M/20M 340M
ThinkPad 755C 9545 486DX4-50/25 4M/32M 170M
9545 486DX4-50/25 4M/32M 340M
9545 486DX4-50/25 4M/32M 540M
9545 486DX4-75/25 4M/32M 170M
9545 486DX4-75/25 4M/32M 340M
9545 486DX4-75/25 4M/32M 540M
ThinkPad 755CD 9545 486DX4-100/33 8M/32M 540M
9545 486DX4-100/33 8M/32M 810M
ThinkPad 755CDV 9545 486DX4-100/33 8M/32M 540M
9545 486DX4-100/33 8M/32M 810M
ThinkPad 755Ce 9545 486DX4-100/33 8M/32M 340M
9545 486DX4-100/33 8M/32M 540M
9545 486DX4-100/33 8M/32M 810M
C Color
M Megabyte
P Pen
T Tablet
TPF ThinkPad File
Introduction 3

Model Type Processor Memory Hrd Dsk
ThinkPad 755Cs 9545 486DX4-50/25 8M/32M 170M
9545 486DX4-50/25 8M/32M 340M
9545 486DX4-50/25 8M/32M 540M
9545 486DX4-75/25 8M/32M 170M
9545 486DX4-75/25 8M/32M 340M
9545 486DX4-75/25 8M/32M 540M
ThinkPad 755Cse 9545 486DX4-100/33 8M/32M 340M
9545 486DX4-100/33 8M/32M 540M
9545 486DX4-100/33 8M/32M 810M
ThinkPad 755CV 9545 486DX4-100/33 8M/32M 540M
9545 486DX4-100/33 8M/32M 810M
ThinkPad 755CV 9545 486DX4-100/33 8M/32M 540M
9545 486DX4-100/33 8M/32M 810M
ThinkPad 760C/CD 9546 Pentium-90 8M/40M 360M
9546 Pentium-120 8M/40M 720M
9546 Pentium-90 8M/40M 810M
9546 Pentium-120 8M/40M 1.2G
ThinkPad 760E/ED 9546 Pentium-120 8M/80M 810M
9546 Pentium-133 8M/80M 1.0G
9546 Pentium-150 8M/80M 1.2G
9546 Pentium-166 8M/80M 1.3G
9546 Pentium-166 8M/80M 2.1G
ThinkPad 760EL/ELD9547 Pentium-100 8M/80M 810M
9547 Pentium-100 8M/80M 1.0G
9547 Pentium-100 8M/80M 1.2G
9547 Pentium-120 8M/80M 810M
9547 Pentium-120 8M/80M 1.0G
9547 Pentium-120 8M/80M 1.2G
9547 Pentium-133 8M/80M 810M
9547 Pentium-133 8M/80M 1.0G
9547 Pentium-133 8M/80M 1.2G
ThinkPad 760L/LD 9546 Pentium-90 8M/40M 810M
9546 Pentium-90 8M/40M 1.1G
9546 Pentium-90 8M/40M 1.2G
9546 Pentium-120 8M/40M 810M
9546 Pentium-120 8M/40M 1.1G
9546 Pentium-120 8M/40M 1.2G
ThinkPad 760X 9546 Pentium-150 32M/80M 3.0G
ThinkPad 760XD 9546 Pentium-166 32M/80M 3.0G
ThinkPad 760XL 9547 Pentium-166 16M/80M 2.1G
9547 Pentium-166 16M/80M 3.0G
ThinkPad 765D 9546 Pentium MMX-166 32M/104M 3.0G
ThinkPad 765L 9547 Pentium MMX-166 32M/104M 3.0G
ThinkPad 770 9548, 9549 Pentium MMX-233 32M/256M 3.2G
ThinkPad 770 9548, 9549 Pentium MMX-233 32M/256M 4.0G
ThinkPad 770 9548, 9549 Pentium MMX-233 32M/256M 5.1G
C Color
M Megabyte
P Pen
T Tablet
TPF ThinkPad File
4IBM Mobile Systems HMM

Drive and Diskette Compatibility Matrix
The following table provides identification information for
3.5-inch drives.
Diskette
Drive Identifying Mark
3.5-Inch - 1.44MB 1.44 on the eject button
3.5-Inch - 2.88MB 2.88 on the eject button
The following table provides compatibility information for
3.5-inch diskettes and 3.5-inch diskette drives.
The following table provides identification information for
5.25-inch diskette drives.
Diskette
Capacity 1.44MB Drive 2.88MB Drive
1.0MB Read/Write Read/Write
2.0MB Read/Write Read/Write
4.0MB Not Compatible Read/Write
Diskette
Drive Identifying Mark
5.25-Inch - 360KB (External) Asterisk on bezel
5.25-Inch - 1.2MB (Internal) 1.2 on the eject button
The following table provides compatibility information for
5.25-inch diskettes and 5.25-inch diskette drives.
Note: A 360KB diskette written to or formatted on a
1.2MB drive can be read reliably only on a 1.2MB
drive.
Diskette
Capacity 360KB Drive 1.2MB Drive
360KB Read/Write Read/Write
1.2MB Not Compatible Read/Write
Introduction 5

Important Service Information
Important
Diskette fixes are customer installable. The diskette
fixes are located on the PC Company Bulletin Board
Service (BBS). The direct phone line for modem
connection is 919-557-0001 or tieline 255-0001.
Advise customers to contact the PC Company
HelpCenter at 800-772-2227 if they need assistance in
obtaining or installing any diskette fixes.
Customers in Canada should call IBM HelpPC at
800-565-3344 for assistance or down-load information.
The Canadian BBS phone numbers are:
Montreal 514-938-3022
Toronto 905-316-4255
Vancouver 604-664-6464
Winnipeg 204-934-2735
FRU Replacement Strategy
Before Replacing Parts
Ensure that all diskette fixes are installed prior to
replacing any FRUs listed in this manual.
Use the following strategy to prevent unnecessary FRU
replacement and service expense:
If you are instructed to replace a FRU and that
does not correct the problem, reinstall the original
FRU before you continue.
Some computers have both a processor board and a
system board. If you are instructed to replace either
the processor board or the system board, and the first
board that you replaced does not correct the problem,
reinstall the original board, then replace the other
(processor or system) board.
If an adapter or device consists of more than one
FRU, an error code may be caused by any of the
FRUs. Before replacing the adapter or device,
remove the FRUs, one by one, to see if the
symptoms change. Replace only the FRU that
changed the symptoms.
Attention
A customized setup configuration (other than default
settings) may exist on the computer you are servicing.
Running Automatic Configuration may alter those
settings. Note the current configuration settings (using
the View Configuration option) and verify that the
settings are in place when service is complete.
6IBM Mobile Systems HMM

The advanced diagnostic tests are intended to test only
IBM products. Non-IBM products or modified options can
give false errors and invalid responses.
Hard Disk Drive Replacement Strategy:
Always try to run a low-level format before replacing a hard
disk drive.
Attention
The drive startup sequence in the computer you are
servicing might have been changed. Be extremely
careful during write operations such as copying,
saving, or formatting. Data or programs can be
overwritten if you select an incorrect drive.
How to Use Error Messages
Use the error codes displayed on the screen to diagnose
failures. If more than one error code is displayed, begin
the diagnosis with the first error code. The cause of the
first error code can result in false error codes being
displayed. If no error code is displayed, see if the error
symptom is listed in the Symptom-to-FRU Index for the
computer you are servicing.
How to Read POST Error Messages
POST error messages are displayed on the screen as
three, four, five, or eight digits. The error messages that
can be displayed as shorter POST messages are
highlighted in this index. Some digits will represent
different information for SCSI errors versus non-SCSI
errors.
The following example shows which digits display the
shorter POST error messages and also defines the SCSI
information in an eight-digit error message.
Shorter POST Messages
┌────┬────┬────┬────┐
│ │ │ │ │
┌────┬────┬────┬────┬────┬────┬────┬────┐
│ ð│ ð│ ð│ ð│ ð│ ð│ ð│ ð│
└────┴────┴────┴────┴────┴────┴────┴────┘
│ │ │ │ │ │ │ │
Reserved ││││││Size (SCSI)
└────┴────┘ │ │ Slot Number (SCSI)
Device Code │ Logical Unit Number (SCSI)
ID (SCSI)
All SCSI devices are set to a different SCSI ID.
Duplicate SCSI ID settings can generate a false error
message. Use the SCSI ID to determine whether the error
message is coming from an internal or an external device.
Introduction 7