Samsung SCH-A310 Service Manual page 51

8-1-3 Abnormal Backlight Operation
Press any button on the phone
'L' level outputted
from U500 pin 15?
YES YES YES YES
'L' level fro m
R558,R559
YES YES
YES YES
END
NO NO NO NO
NO NO NO NO
SAMSUNG Proprietary-Contents may change without notice
Check U500. Replace if required.
Check R588,R559. Replace if required.
8-3
Trouble Shooting