Keypad Backlight Troubleshooting - LG GM750 Service 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
Start
Key press
+VPWR
is above 2.6V?
Yes
KPD_DRV_N is 0V ?
Yes
Check an U201 SMT status
by X-ray
Exchange U201 or
Change the Main board
And Retest
LGE Internal Use Only
Key Backlight LED On
NO
Check battery
Yes
NO
Change the Main board
VPWR
KPD_DRV_N
- 148 -
+ V P W R
R v e 1 . 0 . 9 0 8 0 2 1
L D 5 3 0
R 5 0 3
2 0 2
S S C T - W H 1 4 0 H - L
E R H 0 Y 0 0 5 3 1 0
L D 5 2 0
R 5 8 1
2 0 2
S S C T - W H 1 4 0 H - L
E R H 0 Y 0 0 5 3 1 0
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Only for training and service purposes
K P D _ D R _ V N
D 5 3 0
P R S B 6 8 . C