Samsung SCH-3500 series Service Manual page 35

Trouble Shooting
8-1-3 Abnormal Backlight Operation
Press any button on the phone.
'H' level outputted
from U908 pin 147?
'H' level
from U908 pin 147 drive
Q4 through R35?
Normal Q5 operation?
The voltage applied
to LCD pins 46, 47?
Backlight LED on
NO
YES
NO
YES
NO
YES
NO
YES
SAMSUNG Proprietary-Contents may change without notice
Check U908 pin 147. Replace if required.
Check R34, R35, and Q4.
Replace if required.
Check R28, R29, R30 and
Q5. Replace if required.
Resolder R31 and R32.
8-3