Lcd-Related Symptoms; Intermittent Problems - IBM ThinkPad X20 Hardware Maintenance Manual

The power-on password prompt A power-on password or a
The hard disk password prompt
The DOS-full screen looks
smaller.

LCD-related symptoms

Important:
The TFT LCD for the notebook computer contains many
thin-film transistors (TFTs). 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. The LCD should be replaced if
the number of missing, discolored, or lighted dots in any
background is:
v SVGA(X20, X21): 5 or more bright dots, 5 or more dark
dots, or a total of 9 or more bright and dark dots.
v XGA(X22, X23): 8 or more bright dots, 8 or more dark
dots, or a total of 9 or more bright and dark dots.
Symptom or error
No beep, power-on indicator
on, and a blank LCD during
POST
v LCD backlight not working
v LCD too dark
v LCD brightness cannot be
adjusted
v LCD contrast cannot be
adjusted
v LCD screen unreadable
v Characters missing pixels
v Screen abnormal
v Wrong color displayed
v Horizontal or vertical lines
displayed on LCD

Intermittent problems

Intermittent system hang problems can be due to a variety
of causes that have nothing to do with a hardware defect,
Chapter 3. ThinkPad X20, X21, X22, X23
supervisor password is set.
Type the password and press
Enter.
A hard disk password is set.
Type the password and press
Enter.
Start the ThinkPad
Configuration program and set
the Screen expansion
function.
FRU or action, in sequence
1. System board.
1. Reseat the LCD
connectors.
2. LCD assembly.
3. System board.
1. See important note for

"LCD-related symptoms".

2. Reseat all LCD connectors.
3. LCD assembly.
1. LCD assembly.
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