Lcd-Related Symptoms - IBM ThinkPad R40 Hardware Maintenance Manual

Symptom-to-FRU index

LCD-related symptoms

Im p o rta n t
The TFT LCD for the notebook com puter contains
many thin-film transistors (TFTs). A sm all num ber of
dots that are missing, discolored, or always lighted
is characteristic of TFT LCD technology, but
excessive pixel problem s can cause viewing
concerns. The LCD should be replaced if the
num ber of missing, discolored, or lighted dots in any
background is:
• XG A: 8 or more bright dots, 8 or more dark dots,
or a total of 9 or more bright and dark dots.
• SX G A+: 11 or more bright dots, 13 or more dark
dots, or a total of 16 or more bright and dark
dots.
N ote: A bright dot means a pixel is always on
(white or color.) A dark dot means a pixel is
always off (black color.)
Sym ptom o r error
No beep, power-on indicator
on, and a blank LCD during
POST.
• LCD backlight not working.
• LCD too dark.
• LCD brightness cannot be
adjusted.
• LCD contrast cannot be
adjusted.
• LCD screen unreadable.
• Characters missing pixels.
• Screen abnormal.
• Wrong color displayed.
Horizontal or vertical lines
displayed on LCD.
5 8 ThinkPad R40
FRU o r actio n, in sequence
System b o ard.
1. Reset the LCD
c o n n e c to rs.
2. LCD assembly.
3. System board.
1. See im portant note for
" LCD-related sym p tom s."
2. Reset all LCD connectors.
3. LCD assembly.
4. System board.
LCD asse m bly.