Lenovo T420i LCD-related symptoms, Symptom or error, FRU or action, in sequence, System board

•Lenovo will not provide replacement if the LCD is within specification as we cannot guarantee that any replacement LCD will have zero pixel defects.

•One pixel consists of R, G, B sub-pixels.

Table 6. LCD-related symptoms

Symptom or error		FRU or action, in sequence
No beep, power-on indicator on, and a blank LCD during		System board.
POST.
• LCD backlight not working.		1.	Reseat the LCD connectors.
•	LCD too dark.	2.	LCD assembly.
• LCD brightness cannot be adjusted.		3.	System board.
• LCD contrast cannot be adjusted.
•	LCD screen unreadable.	1.	See important note for “LCD-related symptoms.”
•	Characters missing pixels.	2.	Reseat all LCD connectors.
•	Screen abnormal.	3.	LCD assembly.
•	Wrong color displayed.	4.	System board.
Horizontal or vertical lines displayed on LCD.		LCD assembly.

Chapter 4. Related service information 47