LG 42LF20FR (CHASSIS:LP91A) Service Manual ▷ View online
- 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
)
- 18 -
801
803
805
806
804
802
550
830
540
821
400
521
530
300
120
122
510
500
901
900
200
200T
A10
A9
A2
LV1
EXPLODED VIEW
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These
parts are identified by in the Schematic Diagram and EXPLODED VIEW.
It is essential that these special safety parts should be replaced with the same components as
recommended in this manual to prevent X-RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
parts are identified by in the Schematic Diagram and EXPLODED VIEW.
It is essential that these special safety parts should be replaced with the same components as
recommended in this manual to prevent X-RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
IMPORTANT SAFETY NOTICE
THE SYMBOL MARK OF THIS SCHEMETIC DIAGRAM INCORPORATES
SPECIAL FEATURES IMPORTANT FOR PROTECTION FROM X-RADIATION.
FILRE AND ELECTRICAL SHOCK HAZARDS, WHEN SERVICING IF IS
ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR
THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC.
CVBS_LIN
MUTE_LINE
AUDIO_R
SD05
ZD100
100uF
16
16
V
C
102
SD05
ZD103
SD05
ZD105
MNT_ROUT
CVBS_VIN
SPK_R+_HOTEL
RT1C3904-T112
Q100
E
B
C
SPK_R-_HOTEL
CVBS_RIN
SD05
ZD104
10uF
16V
C101
MUTE_LINE
SD05
ZD101
SD05
ZD102
MNT_LOUT
RT1C3904-T112
Q101
E
B
C
MNT_VOUT
10uF
16V
C100
30V NON_HOTEL_OPT
D102
30V NON_HOTEL_OPT
D103
30V
D101
30V
ADUC30S03010L_AMODIODE
D100
30V
D104
30V
D105
COMP2_Y
COMP2_PB
COMP2_PR
COMP2_L
COMP2_R
S_VIDEO_DET
SIDE_Y
SIDE_C
+3.3V_MULTI_MST
OPT
READY
C104
30V
D106
30V
D107
SD05
ZD106
SD05
ZD107
PSJ014-01
JK101
S-VIDEO
GND
6
1
C-LUG1
2
C-LUG2
3
0-SPRING
4
C-LUG3
5
C-LUG4
SHIELD
7
75
R102
0
HOTEL_OPT
R103
0
HOTEL_OPT
R105
0
NON_HOTEL_OPT
R106
0
HOTEL_OPT
R101
75
R109
75
R108
75
R107
220K
R104
12K
R118
12K
R117
12K
R119
12K
R120
10K
R113
10K
R115
10K
R116
220K
R100
220K
R111
220K
R112
75
R110
75
R122
S-VIDEO
75
R121
S-VIDEO
10K
R123
100pF READY
C103
10K
R114
PPJ226-01
JK100
9A
[GN]1P_CAN
4A
[GN]O-SPRING_A
3A
[GN]CONTACT_A
9B
[BL]1P_CAN
8B
[BL]C-LUG_A
9C
[RD]1P_CAN_1
8C
[RD]C-LUG_A
9D
[WH]1P_CAN
8D
[WH]C-LUG_A_1
9E
[RD]1P_CAN_2
4E
[RD]O-SPRING_A_1
3E
[RD]CONTACT_A_1
9F
[YL]2P_CAN
4F
[YL]O-SPRING_A
3F
[YL]CONTACT_A
9G
[WH]2P_CAN
8G
[WH]C-LUG_A_2
9H
[RD]2P_CAN
4H
[RD]O-SPRING_A_2
3H
[RD]CONTACT_A_2
5J
[YL]O-SPRING_B
6J
[YL]CONTACT_B
7K
[WH]C-LUG_B
5L
[RD]O-SPRING_B
6L
[RD]CONTACT_B
1 9
2008/12/16
INPUT1
MSTAR N-EU
EAX56856904
H6 LCD MERCURY
POP NOISE
MNT_OUT
COMPONENT1
POP NOISE
AV1
COMPONENT1, AV1, MNT_OUT[JACK PACK TYPE D] : JK100
S-VIDEO(China Model)
INPUT1 : COMPONENT1, S-VIDEO
USB_DN
USB_DP
THE SYMBOL MARK OF THIS SCHEMETIC DIAGRAM INCORPORATES
SPECIAL FEATURES IMPORTANT FOR PROTECTION FROM X-RADIATION.
FILRE AND ELECTRICAL SHOCK HAZARDS, WHEN SERVICING IF IS
ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR
THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC.
SIDE_LIN
SIDE_RIN
5.6B
ZD203
SIDE_V
PPJ218-01
JK201
5C
[RD]CONTACT
2C
[RD]U_CAN
4C
[RD]O_SPRING
2B
[WH]U_CAN
3B
[WH]C_LUG
2A
[YL]U_CAN
5A
[YL]CONTACT
4A
[YL]O_SPRING
5.6B
ZD202
USB DOWN STREAM
KJA-UB-4-0004
SIDE_USB
JK204
1
2
3
4
5
IR_OUT
+3.3V_MST
TXD
4.7K
R204
ST3232CDR
IC200
3
C1-
2
V+
4
C2+
1
C1+
6
V-
5
C2-
7
T2OUT
8
R2IN
9
R2OUT
10
T2IN
11
T1IN
12
R1OUT
13
R1IN
14
T1OUT
15
GND
16
VCC
4.7K
R205
RXD
KCN-DS-1-0088
JK200
1
2
3
4
5
6
7
8
9
10
+3.3V_MST
+5VST_MST
6630TGA004K
KCN-DS-1-0089
JK202
1
RED
2
GREEN
3
BLUE
4
GND_1
5
DDC_GND
6
RED_GND
7
GREEN_GND
8
BLUE_GND
9
NC
10
SYNC_GND
11
GND_2
12
DDC_DATA
13
H_SYNC
14
V_SYNC
15
DDC_CLOCK
16
SHILED
SD05
ZD200
DSUB_SDA
PC_VS
SD05
ZD201
ENKMC2837-T112
D211
A
A C
C
PC_B
ENKMC2837-T112
D210
A
A C
C
PEJ024-01
JK203
6B
T_TERMINAL2
8
SHIELD_PLATE
7B
B_TERMINAL2
5
T_SPRING
4
R_SPRING
7A
B_TERMINAL1
6A
T_TERMINAL1
3
E_SPRING
DSUB_SDA
PC_AUD_R
PC_G
DSUB_SCL
CAT24C02WI-GT3
IC201
3
A2
2
A1
4
VSS
1
A0
5
SDA
6
SCL
7
WP
8
VCC
ENKMC2837-T112
D212
A
A C
C
DDC_WP
PC_HS
PC_AUD_L
+5V_MULTI
DSUB_SCL
PC_R
CDS3C30GTH
30V
D202
CDS3C30GTH
30V
D203
ADUC30S03010L_AMODIODE 30V
D200
ADUC30S03010L_AMODIODE 30V
D201
30V
D206
30V
D205
ADUC30S03010L_AMODIODE
30V
D204
ADUC30S03010L_AMODIODE
30V
D209
30V
D208
READY
30V
D207
READY
USB_DL_N
USB_DL_P
0
REAR_USB
R229
0
REAR_USB
R230
USB DOWN STREAM
UB01123-4HHS-4F
JK205
REAR_USB
1
2
3
4
5
0.1uF
C203
0.1uF
C200
0.1uF
C201
0.1uF
C202
0.01uF
C205
0.1uF
C204
0.1uF
C206
0.1uF
C207
100
R202
100
R203
75
R227
220K
R223
READY
220K
R222
READY
12K
R226
12K
R228
75
R211
75
R212
75
R213
4.7K
R214
4.7K
R215
220K
R231
220K
R232
10K
R233
10K
R234
12K
R235
12K
R236
4.7K
R220
4.7K
R221
100
R216
100
R217
100
R218
0.1uF OCP_READY
C208
MIC2009YM6-TR
OCP_READY
IC202
3
ENABLE
2
GND
4
FAULT/
1
VIN
6
V
OUT
5I
L
IM
IT
10uF OCP_READY
C209
120OHM
OCP_READY
L200
+5V_USB
1K
OCP_READY
R209
4.7K OCP_READY
R210
0
Non_OCP
R237
10uF
6.
3V
C210
USB_DL_N
USB_DL_P
68
R207
68
R208
68pF
C213
68pF
C211
4.7K
R219
READY
0
R200
0
R201
500
L201
220uF
16V
C212
100uF
16V
C214
KDS226
D213
OCP_READY
A
AC
C
510 OCP_READY
R238
160
OCP_READY R206
10K
R224
10K
R225
IR_OUT
2 9
INPUT2
MSTAR N-EU
2008/12/16
INPUT2 : PC,RS-232C,SIDE AV,USB
USB
EAX56856904
H6 LCD MERCURY
Itís possibel to 27~47ohm
** 1A Design
SIDE AV
RS-232C (CI ITEM)
PC EDID
PC
PC SOUND
Pin to Pin with
EAN43439401
Close to SIDE_USB
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