Lenovo T420 Tablet User Manual


 
Lenovo will not provide replacement if the LCD is within specication 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
POST.
System board.
LCD backlight not working.
LCD too dark.
LCD brightness cannot be adjusted.
LCD contrast cannot be adjusted.
1. Reseat the LCD connectors.
2. LCD assembly.
3. System board.
LCD screen unreadable.
Characters missing pixels.
Screen abnormal.
Wrong color displayed.
1. See important note for “LCD-related symptoms.”
2. Reseat all LCD connectors.
3. LCD assembly.
4. System board.
Horizontal or vertical lines displayed on LCD. LCD assembly.
Chapter 4. Related service information 47