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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 FRU service procedures before replacing
any FRUs.
Be extremely careful during write operations
(copying, saving, or formatting). Drives in the
computer that you are servicing might have been
rearranged, or the drive startup sequence might
have been 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 FRU part number are correct
by referring to the parts list.
FRUs 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. FRU replacement should be
considered only when a recurring problem exists.
If this is suspected, clear the error log and run
the test again. Do not replace any FRUs if log
errors do not reappear.
Be careful not to replace a nondefective FRU.
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 cause subsequent error codes to be false. If no error
code is displayed, see if the error symptom is listed in the
“Symptom-to-FRU Index” on page 542.
Port Replicator Problems: If you suspect a
problem with the Port Replicator, see “Common Devices
Checkout” on page 681.
How to Diagnose Multiple FRUs: If the adapter
or device has more than one FRU, the error code could be
caused by any one of them. Before replacing multiple
FRUs, try removing or exchanging each FRU, one by one
in the designated sequence, to see if the symptoms
change.
ThinkPad 770 (9548, 9549)
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