IBM ThinkPad 600, Hardware Maintenance Manual, Page: 68 / 124

Symptom-to-FRU Index
LCD-Related Symptoms
Important
The TFT LCD for the notebook computer contains
over 2,359,296 thin-film transistors (TFTs). A small
number of missing, discolored, or lighted dots (on all
the time) is characteristic of TFT LCD technology, but
excessive pixel problems can cause viewing concerns.
The LCD should be replaced if the number of missing,
discolored, or lighted dots in any background is 21 or
more.
Symptom / Error FRU / Action in Sequence
No beep, power-on indicator
on, and a blank LCD during
POST. 1. System board
Ÿ
LCD backlight not
working.
Ÿ
LCD too dark.
Ÿ
LCD brightness cannot
be adjusted.
Ÿ
LCD contrast cannot
be adjusted.
1. Reseat the LCD
connectors.
2. LCD assembly
3. System board
Ÿ
LCD screen
unreadable.
Ÿ
Characters missing
pels.
Ÿ
Screen abnormal.
Ÿ
Wrong color displayed.
1. See important note
for “LCD-Related
Symptoms.”
2. Reseat all LCD
connectors.
3. LCD assembly
4. System board
LCD has extra horizontal or
vertical lines displayed. 1. LCD assembly
Modem (DSP)-Related Symptoms
Symptom / Error FRU / Action in Sequence
In OS/2, DOS, or Windows
multimedia programs, no
sound comes from the
computer. (Only system
beeps are heard at
power-on.) Check that the device
driver is installed
correctly.
In OS/2, DOS, or Windows,
the modem does not work. Check that the DSP
Modem is active.
OS/2 and Windows:
Click on the DSP Modem
icon in the ThinkPad
Configuration program.
DOS:
Run the MWMODEM ON
command.
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