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Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
4. TROUBLE SHOOTING
Regulator
Check TP2,TP3 are 2.8V
NO
YES
Replace
U400
Regulator is OK.
CHECKING FLOW
Fig4-5. Regulator schematic
Fig4-7. Regulator output Voltage
Fig4-4. Regulator placement
U400
TP3
TP2
Check TP1 is 4v
NO
Check
U100
YES
Fig4-6. Regulator Enable voltage
TP1
4V
TP2
TP3
TP1
4.2.1.1 Regulator Circuit
K
C
O
L
B
F
R
0
5
1
1
0
4
R
9
N
I
V
1
1
T
U
O
V
8
7
2
T
U
O
V
W
Q
P
M
M
-
1
1
0
9
T
R
0
0
4
U
2
1
N
E
2
N
E
3
5
D
N
G
1
C
N
4
2
C
N
6
PGND
u
7
.
4
N
Y
S
F
R
V
_
8
V
2
9
0
4
C
E
R
O
C
F
R
V
_
8
V
2
0
0
4
R
I
N
D
T
A
B
V
u
1
1
1
4
C
O
I
V
_
8
V
1
u
7
.
4
8
0
4
C
N
E
_
O
D
L
_
T
X
E
T
P
1
T
P2
T
P3