LCD-related symptoms
Important
The TFTLCD 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 TFTLCD 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:
vXGA: 8 or more bright dots, 8 or more dark dots,
or a total of 9 or more bright and dark dots.
vSXGA+: 11or more bright dots, 13 or more dark
dots, or a total of 16 or more bright and dark
dots.
Note: Abright dot means a pixel is always on
(white or color.)A dark dot means a pixel is
always off (black color.)
Symptomor error FRUor action, in sequence
Nobeep, power-on indicator
on,and a blank LCD during
POST.
Systemboard.
vLCDbacklight not working.
vLCDtoo dark.
vLCDbrightness cannot be
adjusted.
vLCDcontrast cannot be
adjusted.
1. Reseatthe LCD
connectors.
2. LCDassembly.
3. Systemboard.
vLCDscreen unreadable.
vCharactersmissing pixels.
vScreenabnormal.
vWrongcolor displayed.
1. Seeimportant note for
“LCD-relatedsymptoms.”
2. Reseatall LCD connectors.
3. LCDassembly.
4. Systemboard.
Horizontalor vertical lines
displayedon LCD. LCD assembly.
Symptom-to-FRUindex
54 ThinkPad T20, T21, T22, T23 (MT 2647/2648)