Keypad Backlight Troubleshooting - LG KS20 Operating Instructions Manual

4. TROUBLE SHOOTING

4.15 Keypad Backlight Troubleshooting

Key Pad Back Light is on as below :
Key pressing -> KPD_DRV_N go to 0V -> Key Backlight LED On
Start
Key press
+VPWR is above 2.6V?
KPD_DRV_N is 0V ?
Check an U100 SMT status
by X-ray
Exchange U100 or
Change the Main board
And Retest
VPWR
LGE Internal Use Only
NO
Yes
NO
Yes
VPWR
KPD_DRV_N
- 122 -
Check battery
Yes
Change the Main board
or Check the Key FPCB
Power Keypad LED
100ohm R100 LD101
SSC-TWH104-HLS
100ohm R101 LD102
SSC-TWH104-HLS
100ohm R102 LD103
SSC-TWH104-HLS
100ohm R103 LD104
SSC-TWH104-HLS
D107
PRSB6.8C
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Only for training and service purposes
KPD_DRV_N