Toshiba Satellite P20-25 Series User manual

Toshiba Personal Computer
Satellite P20-25 Series
Maintenance Manual
TOSHIBA CORPORATION

ii Satellite P20-25 Series Maintenance Manual
Copyright
© 2003 by Toshiba Corporation. All rights reserved. Under the copyright laws, this manual
cannot be reproduced in any form without the prior written permission of Toshiba. No patent
liability is assumed with respect to the use of the information contained herein.
Toshiba Personal Computer Satellite P20-25 Series Maintenance Manual
First edition June 2003
Disclaimer
The information presented in this manual has been reviewed and validated for accuracy. The
included set of instructions and descriptions are accurate for the P20 Series at the time of this
manual's production. However, succeeding computers and manuals are subject to change
without notice. Therefore, Toshiba assumes no liability for damages incurred directly or
indirectly from errors, omissions, or discrepancies between any succeeding product and this
manual.
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Microsoft, MS-DOS, Windows, DirectSound and DirectMusic are registered trademarks of
Microsoft Corporation.
Intel and Pentium are registered trademarks, and SpeedStep is a trademark of Intel
Corporation.
Sound Blaster is a registered trademark of Creative Technology Ltd.
Centronics is a registered trademark of Centronics Data Computer Corporation.
Photo CD is a trademark of Eastman Kodak.
All other properties are trademarks or registered trademarks of their respective holders.

Satellite P20-25 Series Maintenance Manual iii
Preface
This maintenance manual describes how to perform hardware service maintenance for the
Toshiba Personal Computer Satellite P20 Series, referred to as the P20-25 Series in this
manual.
The procedures described in this manual are intended to help service technicians isolate
faulty Field Replaceable Units (FRUs) and replace them in the field.
SAFETY PRECAUTIONS
Four types of messages are used in this manual to bring important information to your
attention. Each of these messages will be italicized and identified as shown below.
DANGER: “Danger” indicates the existence of a hazard that could result in death or
serious bodily injury if the safety instruction is not observed.
WARNING: “Warning” indicates the existence of a hazard that could result in bodily
injury if the safety instruction is not observed.
CAUTION: “Caution” indicates the existence of a hazard that could result in property
damage if the safety instruction is not observed.
NOTE: “Note” contains general information that relates to your safe maintenance
service.
Improper repair of the computer may result in safety hazards. Toshiba requires service
technicians and authorized dealers or service providers to ensure the following safety
precautions are adhered to strictly.
 Be sure to fasten screws securely with the right screwdriver. If a screw is not fully
fastened, it could come loose, creating a danger of a short circuit, which could cause
overheating, smoke or fire.
 If you replace the battery pack or RTC battery, be sure to use only the same model
battery or an equivalent battery recommended by Toshiba. Installation of the wrong
battery can cause the battery to explode.

iv Satellite P20-25 Series Maintenance Manual
The manual is divided into the following parts:
Chapter 1 Hardware Overview describes the P20-25 Series system unit and each
FRU.
Chapter 2 Troubleshooting Procedures explains how to diagnose and resolve
FRU problems.
Chapter 3 Test and Diagnostics describes how to perform test and diagnostic
operations for maintenance service.
Chapter 4 Replacement Procedures describes the removal and replacement of the
FRUs.
Appendices The appendices describe the following:
 Handling the LCD module
 Board layout
 Pin assignments
 Keyboard scan/character codes
 Key layout
 Screw torque list
 Reliability

Satellite P20-25 Series Maintenance Manual v
Conventions
This manual uses the following formats to describe, identify, and highlight terms and
operating procedures.
Acronyms
On the first appearance and whenever necessary for clarification acronyms are enclosed in
parentheses following their definition. For example:
Read Only Memory (ROM)
Keys
Keys are used in the text to describe many operations. The key top symbol as it appears on
the keyboard is printed in boldface type.
Key operation
Some operations require you to simultaneously use two or more keys. We identify such
operations by the key top symbols separated by a plus (+) sign. For example, Ctrl + Pause
(Break) means you must hold down Ctrl and at the same time press Pause (Break). If
three keys are used, hold down the first two and at the same time press the third.
User input
Text that you are instructed to type in is shown in the boldface type below:
DISKCOPY A: B:
The display
Text generated by the computer that appears on its display is presented in the type face
below:
Format complete
System transferred