General Descriptions; Read This First - IBM ThinkPad X21 2660 Hardware Maintenance Manual

General descriptions

This chapter includes descriptions for any ThinkPad model
that has the PC-Doctor DOS diagnostics program. Some
descriptions might not apply to your particular computer.

Read this first

Before you go to the checkout guide, be sure to read this
section.
Important notes
Only certified trained personnel should service
the computer.
Read the entire FRU removal and replacement
page before replacing any FRU.
Use new nylon-coated screws when you replace
FRUs.
Be extremely careful during such write operations
as copying, saving, or formatting. Drives in the
computer that you are servicing may have had their
start sequence altered. If you select an incorrect
drive, data or programs might be overwritten.
Replace FRUs only for the correct model. When
you replace a FRU, make sure the model of the
machine and the FRU part number are correct by
referring to the FRU parts list.
A FRU should not be replaced because of a
single, unreproducible failure. Single failures can
occur for a variety of reasons that have nothing to do
with a hardware defect, such as cosmic radiation,
electrostatic discharge, or software errors. Consider
replacing a FRU only when a problem reoccurs. If you
suspect that a FRU is defective, clear the error log
and run the test again. If the error does not recur, do
not replace the FRU.
Be careful not to replace a nondefective FRU.
Service applied by an unauthorized/trained Thinkpad
technician may potentially void your warranty
What to do first: When you do return a FRU, you must
include the following information in the parts exchange
form or parts return form that you attach to it:
1. Name and phone number of servicer
2. Date of service
3. Date on which the machine failed
4. Date of purchase
5. Failure symptoms, error codes appearing on the
display, and beep symptoms
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General descriptions