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No Beep Symptoms
Symptom / Error FRU / Action in Sequence
No beep, power-on indicator
not on, and a blank LCD
during POST.
1. Go to “Power
Systems Checkout”
on page 272.
2. System Board
3. Power sources
No beep, power-on indicator
on, and a blank LCD during
POST.
1. System Board
No beep, power-on indicator
on, and a blinking cursor
only during POST.
1. System Board
No beep during POST but
system runs correctly.
1. Turn the volume up
and check the
speaker.
2. Speaker
3. System Board
LCD-Related Symptoms
Important
The LCD for the notebook computer contains over
921000 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 dots satisfies the
following condition:
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
LCD backlight not
working, or
LCD too dark, or
LCD brightness cannot
be adjusted, or
LCD contrast cannot
be adjusted.
1. Reseat the LCD
connectors.
2. LCD Assembly
LCD screen
unreadable, or
Characters missing
pels, or
Screen abnormal, or
Wrong color displayed.
1. See important note
for “LCD-Related
Symptoms.”
2. Reseat all LCD
connectors.
3. LCD Assembly
4. System Board
286 IBM Mobile Systems - ThinkPad HMM Volume 3