IBM MT 2632 manual LCD-related symptoms, Intermittent problems

Symptom-to-FRU index

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:

vSVGA: 5 or more bright dots, 5 or more dark dots, or a total of 9 or more bright and dark dots.

vXGA: 8 or more bright dots, 8 or more dark dots, or a total of 9 or more bright and dark dots.

Note: Bright dots means pixel is always on (white or color.) Dark dots means pixel is always off (black color.)

Symptom or error		FRU or action, in sequence
No beep, power-on indicator		System board.
on, and a blank LCD during
POST.
v LCD backlight not working.		1.	Reseat the LCD
v	LCD too dark.		connectors.
v LCD brightness cannot be		2.	LCD assembly.
	adjusted.	3.	System board.
v LCD contrast cannot be
	adjusted.
v	LCD screen unreadable.	1.	See important note for
v	Characters missing pixels.		“LCD-related symptoms”.
v	Screen abnormal.	2.	Reseat all LCD connectors.
v	Wrong color displayed.	3.	LCD assembly.
		4.	System board.
Horizontal or vertical lines		LCD assembly.
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, such as cosmic radiation, electrostatic discharge, or software errors. FRU replacement should be considered only when a problem recurs.

When analyzing an intermittent problem, do the following:

1.Run the diagnostic test for the system board in loop mode at least 10 times.

2.If no error is detected, do not replace any FRUs.

46ThinkPad A21e