LCD Related Symptoms
The TFT LCD of the notebook computers contain 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. Excessive pixel
problems can cause viewing concerns. The LCD should
be replaced if the number of missing or discolored, or
lighted dots in any colored background is 21 or more.
Symptom/Error FRU/Action
No beep, power-on indicator
on, and a blank LCD during
POST.
1. System Board
2. DC/DC Card
3. Processor Card (370C,
750Ce, 755C, and
755Cs)
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
3. Interposer Card
4. DC/DC Card
LCD screen
unreadable, or
Characters missing
pels, or
Screen abnormal, or
Wrong color displayed.
1. See the preceding
important note.
2. Reseat the all LCD
connectors
3. LCD Assembly
4. System Board
5. Interposer Card
LCD has extra horizontal or
vertical lines displayed.
1. LCD Assembly
Keyboard/TrackPoint II Related
Symptoms
Symptom/Error FRU/Action
Keyboard (one or more
keys) does not work.
1. Reseat the three
keyboard cables.
2. Keyboard
3. Interposer Card
4. System Board
TrackPoint II does not work. 1. Go to “TrackPoint II
checkout” on
page 204.
2. Keyboard
3. Interposer Card
4. System Board
Pointer moves automatically
or does not work correctly.
1. See “TrackPoint II
checkout” on
page 204.
ThinkPad 355x, 360x, 370C, 750x, 755C, 755Cs 223