Lenovo ThinkPad T431s Hardware Maintenance Manual - Page 43

No-beep symptoms, LCD-related symptoms

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Table 4. Beep symptoms (continued) Symptom or error Five short beeps One long and two short beeps FRU or action, in sequence Replace the system board. Replace the system board. No-beep symptoms Table 5. No-beep symptoms Symptom or error No beep, power-on indicator on, LCD blank, and no POST. No beep, power-on indicator on, and LCD blank during POST. The power-on password prompt appears. The hard-disk password prompt appears. FRU or action, in sequence 1. Ensure that every connector is connected tightly and correctly. 2. Reseat memory module. 3. Replace the system board. 1. Reseat memory module. 2. Replace the system board. A power-on password or a supervisor password is set. Type the password and press Enter. A hard disk password is set. Type the password and press Enter. LCD-related symptoms Important: The TFT LCD for the notebook computer contains many thin-film transistors (TFTs). The presence of 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.If the LCD you are servicing has two or less visible defective pixels, it should not be considered faulty. However, if the LCD has three or more visible defective pixels, it will be deemed as defective by Lenovo and it should be replaced. Notes: • This policy applies to all ThinkPad notebooks purchased on 1 January, 2008 or later. • Lenovo will not provide warranty replacement if the LCD is within specifications because 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 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. FRU or action, in sequence Replace the system board. 1. Reseat the LCD connectors. 2. Replace the LCD assembly. 3. Replace the system board. 1. See important note for "LCD-related symptoms." 2. Reseat all LCD connectors. 3. Replace the LCD assembly. 4. Replace the system board. Replace the LCD assembly. Chapter 4. Related service information 37

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Table 4. Beep symptoms (continued)
Symptom or error
FRU or action, in sequence
Five short beeps
Replace the system board.
One long and two short beeps
Replace the system board.
No-beep symptoms
Table 5. No-beep symptoms
Symptom or error
FRU or action, in sequence
No beep, power-on indicator on, LCD blank, and no
POST.
1.
Ensure that every connector is connected tightly
and correctly
.
2. Reseat memory module.
3. Replace the system board.
No beep, power-on indicator on, and LCD blank during
POST.
1.
Reseat memory module
.
2. Replace the system board.
The power-on password prompt appears.
A power-on password or a supervisor password is set.
Type the password and press
Enter
.
The hard-disk password prompt appears.
A hard disk password is set. Type the password and
press
Enter
.
LCD-related symptoms
Important:
The TFT LCD for the notebook computer contains many thin-film transistors (TFTs). The
presence of 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.If the LCD you are servicing has
two or less visible defective pixels, it should not be considered faulty. However, if the LCD has three or more
visible defective pixels, it will be deemed as defective by Lenovo and it should be replaced.
Notes:
• This policy applies to all ThinkPad notebooks purchased on 1 January, 2008 or later.
• Lenovo will not provide warranty replacement if the LCD is within specifications because 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.
Replace the 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. Replace the LCD assembly.
3. Replace the 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. Replace the LCD assembly.
4. Replace the system board.
Horizontal or vertical lines displayed on LCD.
Replace the LCD assembly
.
Chapter 4
.
Related service information
37