Lenovo ThinkPad T400s, Hardware Maintenance Manual

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LCD-related symptoms
Table 6. LCD-related symptoms
Symptom or error FRU or action, in sequence
No beep, power-on indicator on, and a
blank LCD during POST. System board .
v
LCD backlight not working.
v
LCD too dark.
v
LCD brightness cannot be adjusted.
v LCD contrast cannot be adjusted.
1.
Reseat the LCD connectors .
2. LCD assembly.
3. System board.
v LCD screen unreadable.
v
Characters missing pixels.
v Screen abnormal.
v
Wrong color displayed.
1. See important note for “LCD-related
symptoms.”
2. Reseat all LCD connectors.
3. LCD assembly.
4.
System board.
Horizontal or vertical lines displayed on
LCD.
LCD assembly
.
Important: The TFT LCD for the notebook computer contains many thin-film
transistors (TFTs). The presence of a small number of dots that are missing,
discolored, or always lighted is characteristic of TFT LCD technology, but
excessive pixel problems can cause viewing concerns.
If the LCD you are servicing has two or less visible defective pixels, it should not
be considered faulty. However, if the LCD has three or more visible defective
pixels, it will be deemed as defective by Lenovo and it should be replaced.
Notes:
v
This policy applies to all ThinkPad Notebooks purchased on 1 January,
2008 or later.
v
Lenovo will not provide replacement if the LCD is within specification as
we cannot guarantee that any replacement LCD will have zero pixel defects.
v
One pixel consists of R, G, B sub-pixels.
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ThinkPad T400s Hardware Maintenance Manual