LG 42LH20R, Service Manual

Page: 17 / 28

LGE Internal Use Only Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes - 17 -
BLOCK DIAGRAM
RG
B
_
P
C
PC
_
A
u
d
io
TV (R
F
)
CO
M
P
1
HD
M
I1
HD
M
I2
RS
2
3
2
TX
232
C
D
riv
e
r
S
T
3232
C
T
x
/
R
x
:
15V
p
p
P
C
_
R
/G
/B
/
H
S
/
V
S
PC
_
A
u
d
io
_
L
/
R
:
70
0m
V
rms
MNT
_
O
U
T
:
1V
p
p
SI
D
E
_
V
:
1V
p
p
SI
D
E
_
L
/
S
ID
E
_
R
:
500mV
rms
D
D
R
2(
51
2M
B)
L
_
S
PK_
O
U
T
R
_
SP
K_
O
U
T
E
EPR
O
M
24C
0
2
Co
m
p
1
_
L
/
R
:
500mV
rms
TU
N
E
R
AV
1
_
V
IN
:
1V
p
p
A
V
11_
L
IN
/
R
IN
:
50
0m
V
rms
PW
M
N
T
P
3
100L
MNT
_
O
U
T
MNT
_
LO
U
T
/
R
O
U
T
:
5
00m
V
rm
s
AV
2
(S
id
e
A
V
)
M
A
IN
S
C
A
L
E
R
T
X
D
/
R
X
D
:
5V
Di
g
it
a
l
CO
M
P
1
_
Y
/
P
b
/
P
r
:
1/
0.
7
V
p
p
CO
M
P
2
_
Y
/
P
b
/
P
r
: 1
/
0.
7
V
p
p
IR H
D
MI
_
D
AT
A_
1
H
D
MI
_
D
AT
A_
2
H
D
M
I1
_
SC
L
/
SD
A
O
U
T_
E
_
TX
_
C
L
K
O
U
T_
E
_
TX
_
E
O
U
T_
E
_
TX
_
D
O
U
T_
E
_
TX
_
C
O
U
T_
E
_
TX
_
B
O
U
T_
E
_
TX
_
A
TU
_
M
A
IN
S I
F
CO
M
P
1
_
Y
/
P
b
/
P
r
1
/
0.
7V
p
p
AV
1
_
V
IN
P
C
_A
u
d
io
_L
/
R
CO
M
P
1
_
L
IN
/
R
IN
L_
C
H
R_C
H
LV DS co nnec tor
TU
_
M
A
IN
SU
B
_
SC
L
SD
A
E
EPR
O
M
24C
0
2
E
EPR
O
M
24C
0
2
SI
F
AV
1
_
LI
N/
R
IN
MNT
_
L/
R
O
U
T
AV
1
MN
T
_
O
U
T
Co
m
p
2
_
L
/
R
:
500mV
rms
CO
M
P
2
_
Y
/
P
b
/
:
1/
0
.7
V
p
p
CO
M
P
2
_
L
IN
/
R
IN
CO
M
P
2
O
U
T_
O
_
TX
_
C
L
K
O
U
T_
O
_
TX
_
E
O
U
T_
O
_
TX
_
D
O
U
T_
O
_
TX
_
C
O
U
T_
O
_
TX
_
B
O
U
T_
O
_
TX
_
A
P
C
_
R
/G
/B
/
H
S
/
V
S
H
D
M
2
_
S
CL
/
S
DA
P
C
_
S
CL
/
S
DA
MNT
_
V
O
U
T
AV
2
_
V
IN
AV
2
_
LI
N/
R
IN
II
S
_
O
U
T
US
B
US
B
_
D
N
/
P
N
AU
D
IO
AMP
H
D
M
I3
_
SC
L
/
SD
A
E
EPR
O
M
24C
0
2
H
D
MI
_
D
AT
A_
3
TM
D
S
TM
D
S
TM
D
S
HD
M
I3
US
B
Fo
r D
/
L
E
E
PR
O
M
(2
5
6
K)
S
e
ri
al
F
las
h
(8
M
B
y
te
)
RG
B
_
P
C
PC
_
A
u
d
io
TV (R
F
)
CO
M
P
1
HD
M
I1
HD
M
I2
RS
2
3
2
TX
232
C
D
riv
e
r
S
T
3232
C
±
P
C
_
R
/G
/B
/
H
S
/
V
S
PC
_
A
u
d
io
_
L
/
R
:
70
0m
V
rms
MNT
_
O
U
T
:
1V
p
p
SI
D
E
_
V
:
1V
p
p
SI
D
E
_
L
/
S
ID
E
_
R
:
500mV
rms
D
D
R
2(
51
2M
B)
E
EPR
O
M
24C
0
2
Co
m
p
1
_
L
/
R
:
500mV
rms
TU
N
E
R
AV
1
_
V
IN
:
1V
p
p
A
V
11_
L
IN
/
R
IN
:
50
0m
V
rms
PW
M
N
T
P
3
100L
MNT
_
O
U
T
MNT
_
LO
U
T
/
R
O
U
T
:
5
00m
V
rm
s
AV
2
(S
id
e
A
V
)
M
A
IN
S
C
A
L
E
R
T
X
D
/
R
X
D
:
5V
Di
g
it
a
l
CO
M
P
1
_
Y
/
P
b
/
P
r
:
1/
0.
7
V
p
p
CO
M
P
2
_
Y
/
P
b
/
P
r
: 1
/
0.
7
V
p
p
H
D
MI
_
D
AT
A_
1
H
D
MI
_
D
AT
A_
2
_
O
U
T_
E
_
TX
_
C
L
K
±
O
U
T_
E
_
TX
_
±
O
U
T_
E
_
TX
_
±
O
U
T_
E
_
TX
_
C
±
O
U
T_
E
_
TX
_
B
±
O
U
T_
E
_
TX
_
A
±
TU
_
M
A
IN
S I
F
CO
M
P
1
_
Y
/
P
b
/
P
:
1
/
0.
7V
p
p
AV
1
_
V
IN
P
C
_A
u
d
io
_L
/
R
CO
M
P
1
_
L
IN
/
R
IN
L_
C
H
R_C
H
LV DS co nnec tor
TU
_
M
A
IN
/
E
EPR
O
M
24C
0
2
E
EPR
O
M
24C
0
2
SI
F
AV
1
_
LI
N/
R
IN
MNT
_
L/
R
O
U
T
AV
1
MN
T
_
O
U
T
Co
m
p
2
_
L
/
R
:
500mV
rms
CO
M
P
2
_
Y
/
P
b
/P
r
1/
0
.7
V
p
p
CO
M
P
2
_
L
IN
/
R
IN
CO
M
P
2
O
U
T_
O
_
TX
_
C
±
O
U
T_
O
_
TX
_
E
±
O
U
T_
O
_
TX
_
D
±
O
U
T_
O
_
TX
_
C
±
O
U
T_
O
_
TX
_
B
±
O
U
T_
O
_
TX
_
A
±
P
C
_
R
/G
/B
/
H
S
/
V
S
P
C
_
S
CL
/
S
DA
P
C
_
S
CL
/
S
DA
MNT
_
V
O
U
T
AV
2
_
V
IN
AV
2
_
LI
N/
R
IN
II
S
_
O
U
T
US
B
US
B
_
D
N
/
P
N
AU
D
IO
AMP
H
D
M
I3
_
SC
L
/
SD
A
H
D
M
I3
_
SC
L
/
SD
A
E
EPR
O
M
24C
0
2
H
D
MI
_
D
AT
A_
3
TM
D
S
TM
D
S
TM
D
S
HD
M
I3
US
B
Fo
r D
/
L
E
E
PR
O
M
(2
5
6
K)
S
e
ri
al
F
las
h
(8
M
B
y
te
)