Keypad Backlight Troubleshooting - LG KU380 Service Manual

4.14 Keypad Backlight Troubleshooting

Key Pad Back Light is on as below :
Key pressing → KYBD_BACKLIGHT go to 0V → MAIN Key Backlight LED On
Start
Key press
+VPWR is above 3.2V?
KYBD_BACKLIGHT is 0V ?
Backlight LED ON?
Change the Main boa rd
LD400
SSC-SWTS1007
1
+VPWR
A
KYBD_BACKLIGHT
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Only for training and service purposes
NO
Yes
NO
Yes
YES
No
R411
2
C
100ohm
Figure.Keypad backlight LED part
4. TROUBLE SHOOTING
Check b attery
Yes
Change the Main boa rd
END
+VPWR
- 105 -
LGE Internal Use Only