VBAT
1u
C711
R711
47
1u
C710
R716
10
R717
10
R715
12K
R714 12K
LD701
LD700
R709
0
47
R712
R713
DNI
Q700
KTC4075E
2
3
1
DNI
R710
MLED
SUB_KEY_BL
UPPER_KEY_BL
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Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
5. TROUBLE SHOOTING
5.10 Keypad back light trouble
Check Points
-Signal path is connected well
-Analog SW is working properly
Slide Key Matrix and LEDs on KEY PCB
TP1
TP4
680
R706
R707
680
UP
OK
680
R708
MENU
SEND
R705
680
LEFT
CLEAR
SELECT
RIGHT
680
R703
DOWN
KP_IN(6)
KP_OUT(0)
KP_OUT(2)
KP_OUT(3)
KP_OUT(4)
KP_IN(5)
KP_OUT(1)
KP_OUT(0:4)
KP_IN(5:6)
VOUT
B4
D1
WPWMIN
LED2
C2
C1
LED3
B1
LED4
B2
LED5
LEDFL
A2
F5
SBIAS
F3
SSENS
A1
T1
T2
A6
F6
T3
T4
F1
BD6095GUL
D3
FLASHCNT
E4
GC1
GC2
E3
F2
LDO1O
LDO2O
E2
LED1
D2
U700
TP700
2.2u
C709
FLASHCNT
SUB_KEY_BL
LCD_PWM
MLED1
MLED2
MLED3
MLED4
MLED
MLED5