LG GD330 - Main Key Backlight LED Trouble Shooting

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4. TROUBLE SHOOTING
4.18. Main Key Backlight LED Trouble Shooting
z Keypad backlight LED Operation scheme is shown below.
z Backlight operation
- Keypad backlight LED is controlled with LED_BC signal
- LED_BC signal from DBB(U100)
- The LEDs are forward biased and turned on
z Check Point
- VBAT level ( 3.35 ~4.2V)
-LEDs
- Main key, Main, Main FPCB connection
TP1_F TP2_F
TP1
TP2
10
6
R
0
1
0
06
D
L
T
A
B
V
0
1
1
06D
L
0
06R
C_DEL_M
U
N
1
00
6
R
106R
1
10
6
DL
0
06D
L
C
_
D
E
L
_
I
V
A
N
A_
D
E
LM