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LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
LGE Internal Use Only
START
YES
Are all LEDs
Working?
NO
YES
Backlight will work properly.
Replace or resolder
component
CHECKING FLOW
Power save mode?
YES
NO
YES
NO
Is the Duty cycle of LED
(60%)?
Are all LEDs
not Working?
Check the soldering
each R and LED
NO
Resolder U103
If on, R121,R122,R123,R124
R125,R126,R127,R128 =0~500mV?
Resolder U103,CN301,CN103
NO
NO
YES
YES
500us
300us
T19
WDDI
WDDQ
T18
R19
WUDI
WUDQ
R18
T20
UCLK
P18
USB_DM
N18
USB_DP
M13
USB_ID
TCK
A9
TDI
B12
LIGHT1
F18
LIGHT2
G17
LIGHT3
G18
KEYON
K22
KEYOUT
L20
KEY_BACKLIGHT2
KEY_BACKLIGHT3
USB_P
USB_N
POWERKEY
KEY_ROW4
B
o
t
B
Y
E
K
O
T
N
I
A
M
3
0
3
D
C
8
.
6
B
S
R
P
3
4
5
6
7
8
9
1
0
3
N
C
G
7
4
1
0
2
7
K
X
A
1
0
5
9
1
0
0
Y
B
N
E
1
1
1
0
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
1
2
0
2
MSMF05C-P
EDTY0008604
D302
T
A
B
V
EDTY0008604
D304
MSMF05C-P
6
0
0
1
_
E
D
O
I
D
_
I
N
D
5
0
3
D
3
W
O
R
_
Y
E
K
1
W
O
R
_
Y
E
K
0
W
O
R
_
Y
E
K
2
W
O
R
_
Y
E
K
4
W
O
R
_
Y
E
K
1
L
O
C
_
Y
E
K
4
L
O
C
_
Y
E
K
3
T
H
G
I
L
K
C
A
B
_
Y
E
K
Y
E
K
R
E
W
O
P
2
T
H
G
I
L
K
C
A
B
_
Y
E
K
3
L
O
C
_
Y
E
K
5
W
O
R
_
Y
E
K
2
L
O
C
_
Y
E
K
0
L
O
C
_
Y
E
K
U103