LG 42LT760H-SA (CHASSIS:LJ3AZ) Service Manual ▷ View online
- 21 -
AV / RGB-PC Audio in Trouble Shooting guide
Check input signal format.
Is it supported?
Y
Check AC cable for damage
For damage or open conductor
Y
Check JK4600/JK3604
Can you see the normal waveform?
Y
Check the input of MTK(IC105).
Measure waveform at C610, C611, C319, C320 because it’s more easy to check.
Can you see the normal waveform?
Y
This board has big problem because Main chip (MTK) have some troubles.
After checking thoroughly all path once again, You should decide to replace MTK or not.
Replace JK4600/JK3604
N
Check Audio AMP output
L5402,L5403,L5404,L5405
Replace L5402,L5403,L5404,L5405
N
Y
HDMI Audio in Trouble Shooting guide
Check input signal format.
Is it supported?
Y
Check AC cable for damage
For damage or open conductor
Y
Check JK3301/JK3302/JK3303
Can you see the normal waveform?
Y
This board has big problem because Main chip (MTK) have some troubles.
After checking thoroughly all path once again, You should decide to replace MTK or not.
Replace JK3301, JK3302, JK3303
N
Check Audio AMP output
L5402,L5403,L5404,L5405
Replace
L5402,L5403,L5404,L5405
N
Y
- 22 -
BLOCK DIAGRAM
LG
E2
11
2
(EU
C
C
om
m
erc
ia
l)
SP
D
IF
O
U
T
N
A
N
D
Fla
sh
(2
G
b)
U
SB
C
VB
S(M
)
Se
ria
l T
S D
ata
U
S
B
1
P
C
-R
G
B
E
x
t. S
P
K
S
P
D
IF
LA
N
SY
ST
EM
D
D
R
3 X
4
(2
G
b)
H
D
M
I3
H
D
M
I2
Si
de
R
ea
r
Eth
ern
et
C
VB
S
SY
ST
EM
E
EP
R
O
M
X
1
(2
56
K
b)
H
D
M
I
S
/W
LV
D
S
Eth
ern
et
H
U
B
IC
R
F
N
TSC
PA
L-M/
N
SIF
Pro
:id
io
m
R
S-2
32
C
A
/V
D
em
od
Ex
t S
PK
A
M
P
51
P
(F
H
D
)
30
P(H
D
D
)
H
D
M
I1
PC
A
ud
io
W
i-F
i
S
pe
ak
er
I2
S
O
ut
A
ud
io
A
M
P
H
D
C
P
EE
PR
O
M
PH
Y
C
hip
IR
&
K
ey
A
U
X
L
A
N
42
32
L
R
R
ea
r
In
te
llig
en
t
Se
ns
or
N
EC
Su
b M
ico
m
C
LO
C
K
D
isp
lay
TS
U
R
A
T
R
G
B
, H
/V
Ex
t. S
pe
ak
er R
/L
Vo
l+/-
Ex
t. Sp
ea
ke
r
L/R
O
U
T
Vo
l C
on
tro
l
R
G
B
PC
R
G
B
,H
/V
A
ud
io
C
LK
S/W
U
S
B
2
M
a
g
ic
W
O
L
R
e
a
lte
k W
O
L
T
o
M
IC
O
M
TS
_S
eri
al_
IN
C
VBS,
L/
R
- 23 -
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.
IMPORTANT SAFETY NOTICE
LV
1
30
0
20
0
80
0
54
0
52
1
53
0
40
1
55
0
81
0
12
0
50
0
57
0
50
1
51
0
40
0
90
0
91
0
A2
A4
A1
0
* Set + Stand * Stand Base + Body
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.
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.
MODEL_OPT_2
JTRST#
STB_SCL
SOC_RX
0 . 1 u F
C116
1K
R150
MODEL_OPT_0
1K
OPT
R147
2.7K
R166
OPT
EMMC_CLK
1K
R151
OPT
OSDA0
OSDA1
+3.3V_NORMAL
MODEL_OPT_8
MODEL_OPT_6
1K
R148
JTMS
SOC_TX
4.7K
R103
EMMC_DATA[2-7]
4.7K
R168
OPT
4.7K
OPT
OPT
R157
33
R158
OPT
MODEL_OPT_1
JTDI
MODEL_OPT_1
LED_PWM0
MT5369_XTAL_OUT
SDA_NVRAM
MT5369_XTAL_IN
AVDD_33SB
JTCLK
MODEL_OPT_5
A_DIM
AVDD_33SB
MODEL_OPT_3
MODEL_OPT_10
1K
R153
OPT
LED_PWM1
JTDO
0 . 1 u F
C118
OSCL0
VDD3V3
LED_PWM1
33
R136
MODEL_OPT_5
MODEL_OPT_3
MODEL_OPT_0
ERROR_OUT
MODEL_OPT_6
+3.3V_NORMAL
MODEL_OPT_9
10K
R174
OPCTRL3
EMMC_CLK
10K
R169
OPT
22
R171
22
R170
OSCL1
PWM_DIM2
33
R137
4.7K
R161
OPT
4.7K
OPT
OPT
R178
PWM_DIM1
LED_PWM0
IR
1K
R154
0 . 1 u F
C117
SCL_NVRAM
STB_SDA
27MHz
X100
MT5369_XTAL_OUT
MT5369_XTAL_IN
+3.3V_NORMAL
33
R143
MTK_JTAG
JTMS
+3.3V_NORMAL
10K
R144
1K
R152
MTK_JTAG
JTDO
JTRST#
JTCLK
JTDI
10K
AR100
10K
R149
MTK_JTAG
10K
R146
MTK_JTAG
10K
R145
MTK_JTAG
+3.3V_NORMAL
2.7K
R139
OSDA2
I2C_SDA2
33
R117
+3.3V_NORMAL
33
R115
I2C_SDA6
2.7K
R188
I2C_SCL4
I2C_SDA4
OSCL2
I2C_SCL5
33
R122
2.7K
R160
33
R116
I2C_SDA5
2.7K
R142
OSCL0
I2C_SCL2
STB_SDA
33
R111
33
R123
2.7K
R134
I2C_SDA1
I2C_SCL3
33
R114
33
R110
OSCL1
I2C_SCL6
I2C_SDA3
33
R113
2.7K
R164
OSDA1
2.7K
R173
2.7K
R156
33
R118
2.7K
R185
OSDA0
2.7K
R177
33
R112
I2C_SCL1
33
R121
STB_SCL
10K
R176
10K
R162
10K
R163
/TU_RESET
EXT_SPK_DET
OPCTRL3
DSUB_DET
OPCTRL_1_SCL
OPCTRL_11_SCL
/S2_RESET
4.7K
MTK_DVB_T2_TUNER
R140
4.7K
MTK_Int_FRC/URSA5
R106
4.7K
MTK_CP_BOX
R135
4.7K
MTK_FRC3/URSA5
R101
4.7K
MTK_EPI
R189
4.7K
MTK_DVB_C2_TUNER
R186
4.7K
MTK_OPTIC_Tx_IC
R125
4.7K
MTK_3D_DEPTH_IC
R130
4.7K
MTK_FHD
R108
4.7K
MTK_DVB_S_TUNER
R175
4.7K
MTK_DDR_768MB
R132
4.7K
MTK_NON_EPI
R190
4.7K
MTK_NON_OPTIC_Tx_IC
R127
4.7K
MTK_DDR_DEFAULT
R133
4.7K
MTK_NON_3D_DEPTH_IC
R129
4.7K
MTK_NON_DVB_T2_TUNER
R141
4.7K
MTK_NO_FRC/Int_FRC
R102
4.7K
MTK_NON_CP_BOX
R138
4.7K
MTK_HD
R109
4.7K
MTK_NON_DVB_C2_TUNER
R187
4.7K
MTK_NON_DVB_S_TUNER
R184
4.7K
MTK_NO_FRC/FRC3
R107
OPCTRL_0_SDA
OPCTRL_10_SDA
OPCTRL_1_SCL
OPCTRL_11_SCL
OPCTRL_0_SDA
OPCTRL_10_SDA
0 . 1 u F
16V
C101
22
R191
+3.3V_NORMAL
22
R192
I2C_SCL1
4.7K
R181
I2C_SDA1
+3.3V_NORMAL
+3.3V_NORMAL
4.7K
R159
12507WS-12L
P100
MTK_JTAG
1
2
3
4
5
6
7
8
9
10
11
12
13
2 . 2 u F
10V
10V
C120
OPT
10K
R193
NON_EU
/S2_RESET
1.2K
R128
1.2K
R131
EMMC_DATA[0]
EMMC_DATA[1]
EMMC_CMD
24pF
C115
24pF
C113
LGE2112
IC105
JTCK
AP14
JTDI
AM14
JTDO
AR14
JTMS
AR15
JTRST
AN14
OSDA0
AP12
OSCL0
AN12
OSDA1
AP15
OSCL1
AN15
XTALI
AT34
XTALO
AU34
AVDD33_XTAL_STB
AK27
AVSS33_XTAL_STB
AH26
AVDD33_VGA_STB
AK18
AVSS33_VGA_STB
AK17
AVDD33_PLLGP
AK23
AVSS33_PLLGP
AM27
AVDD10_LDO
AJ20
GPIO0
H32
GPIO1
F37
GPIO2
F36
GPIO3
G37
GPIO4
G36
GPIO5
G35
GPIO6
G34
GPIO7
H34
GPIO8
L34
GPIO9
L32
GPIO10
K33
GPIO11
K32
GPIO12
H33
GPIO13
L35
GPIO14
K36
GPIO15
J 3 2
GPIO16
J 3 4
GPIO17
K34
GPIO18
K35
GPIO19
K37
GPIO20
J 3 6
GPIO21
J 3 7
GPIO22
J 3 5
GPIO23
J 3 3
GPIO24
G33
GPIO25
H35
GPIO26
H31
GPIO27
F34
GPIO28
E36
GPIO29
N33
GPIO30
P32
GPIO31
M35
GPIO32
M37
GPIO33
M33
GPIO34
F35
GPIO35
E35
GPIO36
E37
GPIO37
N32
GPIO38
M34
GPIO39
M36
GPIO40
M32
GPIO41
L33
GPIO42
E33
GPIO43
E32
GPIO44
F32
GPIO45
A29
GPIO46
D31
GPIO47
C31
GPIO48
E30
GPIO49
E31
GPIO50
F31
GPIO51
E29
GPIO52
AP9
GPIO53
AT9
GPIO54
AR9
GPIO55
AU9
ADIN0_SRV
AN23
ADIN1_SRV
AN24
ADIN2_SRV
AP23
ADIN3_SRV
AR23
ADIN4_SRV
AU23
ADIN5_SRV
AT23
ADIN6_SRV
AM24
ADIN7_SRV
AM23
U0TX
AR18
U0RX
AP18
U1RX
AU16
U1TX
AT16
POWE
A35
POOE
C33
POCE1
B34
POCE0
D33
PDD7
D29
PDD6
C30
PDD5
D30
PDD4
B31
PDD3
A31
PDD2
B32
PDD1
A32
PDD0
C32
PARB
D32
PACLE
A34
PAALE
C34
EMMC_CLK
C29
OPWRSB
AM20
ORESET
AM22
OIRI
AU21
FSRC_WR
D27
STB_SCL
AT21
STB_SDA
AR21
DEMOD_RST
T34
DEMOD_TSCLK
T32
DEMOD_TSDATA0
T36
DEMOD_TSDATA1
U36
DEMOD_TSDATA2
T33
DEMOD_TSDATA3
T30
DEMOD_TSDATA4
V33
DEMOD_TSDATA5
V32
DEMOD_TSDATA6
V31
DEMOD_TSDATA7
V30
DEMOD_TSSYNC
T35
DEMOD_TSVAL
T31
CI_INT
N36
CI_TSCLK
T37
CI_TSDATA0
R35
CI_TSSYNC
R37
CI_TSVAL
R36
PVR_TSCLK
R34
PVR_TSVAL
R32
PVR_TSSYNC
R33
PVR_TSDATA0
P33
PVR_TSDATA1
P34
SPI_CLK1
N37
SPI_CLK
P35
SPI_DATA
N34
SPI_CLE
N35
OPWM2
AU12
OPWM1
AT12
OPWM0
AR12
SD_D0
A37
SD_D1
C35
SD_D2
A36
SD_D3
B35
SD_CMD
B36
SD_CLK
B37
LDM_CS
AT11
LDM_CLK
AU11
LDM_VSYNC
AR10
LDM_DO
AM9
LDM_DI
AP10
LED_PWM1
AN22
LED_PWM0
AP21
OPCTRL11
AU20
OPCTRL10
AT20
OPCTRL9
AN18
OPCTRL8
AP20
OPCTRL7
AM18
OPCTRL6
AN19
OPCTRL5
AP19
OPCTRL4
AR19
OPCTRL3
AN21
OPCTRL2
AM19
OPCTRL1
AN20
OPCTRL0
AR20
MTK_NEC_TX
MTK_NEC_RX
LAN1_DET
0 . 1 u F
C106
OPT
0 . 1 u F
C102
OPT
1K
PWM1_PULL_DOWN_1K
R197
1K
PWM2_PULL_DOWN_1K
R198
USB_CTL1
/USB_OCD1
100
R1010
100
R1016
100
R1025
/USB_OCD2
USB_CTL2
0 . 1 u F
OPT
C123
0 . 1 u F
OPT
C122
M24C16-R
HDCP_EEPROM_ST
IC100
3
NC_3
2
NC_2
4
VSS
1
NC_1
5
SDA
6
SCL
7
WC
8
VCC
24LC16B
HDCP_EEPROM_MICRO
IC100-*1
3
A2
2
A1
4
VSS
1
A0
5
SDA
6
SCL
7
WP
8
VCC
I2C_SCL4
I2C_SDA4
33
OPT
R1030
33
OPT
R1031
2 . 2 u F
10V
C107
2 . 2 u F
10V
10V
C108
HDMI_CEC
0
OPT
R1014
+3.5V_ST
+3.5V_ST
AV_DET
OPC_EN
M24M01-HRMN6TP
IC104
3
E2
2
E1
4
VSS
1
NC
5
SDA
6
SCL
7
WP
8
VCC
WARM_MODE
10K
R1002
OPT
0 . 1 u F
16V
16V
C114
MMBT3904(NXP)
Q1001
OPT
E
B
C
+3.3V_NORMAL
100
R1003
OPT
22
R172
10K
R155
OPT
SOC_RESET
LAN2_DET
33
R1015
4.7K
R105
OPT
4.7K
R104
OPT
2.7K
R182
2.7K
R183
8pF
50V
50V
1 2 p F C r y s t a l
C115-*1
27.0MHZ
1 2 p F C r y s t a l
X100-*1
8pF
50V
50V
1 2 p F C r y s t a l
C113-*1
RF_SWITCH_CTL
100
R1034
OPT
FE_TS_CLK
FE_TS_SYNC
FE_TS_VAL_ERR
TS_S_IN_0_SYNC
TS_S_IN_0_DATA
TS_S_IN_0_VAL
TS_S_IN_0_CLK
TS_S_OUT_VAL
TS_S_OUT_SYNC
TS_S_OUT_DATA
TS_S_OUT_CLK
SERIAL_TS_DATA
22
R1035
22
R1036
22
R1038
22
R1037
0
R1005
RF_SWITCH_CTL
MDS62110205
M24
MDS62110213
M22
MDS62110213
M20
MDS62110213
M23
MDS62110213
M21
EMMC_DATA[7]
EMMC_DATA[6]
EMMC_DATA[4]
EMMC_DATA[2]
EMMC_DATA[3]
EMMC_DATA[5]
8
MID_MAIN_1
2 0 1 1 . 0 9 . 2 9
LG FRC2
3D DEPTH
T 2 T u n e r
M O D E L O P T I O N 8 i s j u s t f o r C P B o x
I t s h o u l d n o t b e a p p i l e d a t M P
NON_3D_Depth_IC
S T u n e r
SoC
i n t e r n a l
FRC
NON_OPTIC
MODEL_OPT_9
OPTIC
1
MODEL_OPT_7
MODEL_OPT_3
S u p p o r t
FHD
W r i t e P r o t e c t i o n
- L o w : N o r m a l O p e r a t i o n
- H i g h : W r i t e P r o t e c t i o n
D i s a b l e
R e s e r v e d
DDR_768MB
EPI
R e s e r v e d
MODEL_OPT_2
DDR
MODEL_OPT_6
HIGH
MODEL_OPT_8
MODEL_OPT_0
N o t S u p p o r t
D e f a u l t
1
N o t S u p p o r t
CP BOX
MODEL_OPT_5
0
0
S u p p o r t
E n a b l e
LOW
1
NO_FRC
NVRAM
M o d e l O p t i o n
0
C l o s e t o e M M C F l a s h
( I C 8 1 0 0 )
MODEL_OPT_10
0
HD
S T R A P P I N G L E D _ P W M 0 L E D _ P W M 1 O P C T R L 3
I C E m o d e + 2 7 M + S e r i a l b o o t 0 0 0
I C E m o d e + 2 7 M + R O M t o N a n d b o o t 0 0 1
I C E m o d e + 2 7 M + R o m t o e M M C b o o t 0 1 0
f r o m e M M C p i n s ( s h a r e p i n s w / s N A N D )
I C E m o d e + 2 7 M + R O M t o e M M C b o o t 0 1 1
f r o m S D I O p i n s
DDR_Default
MODEL_OPT_1
1
MODEL_OPT_4
3D_Depth_IC
X-TAL
JTAG
I2C
I2C_1 : AMP, L/DIMMING,HDCP KEY
I2C_2 : T-CON
I2C_3 : MICOM
I2C_4 : S/Demod,T2/Demod, LNB
I2C_5 : NVRAM
I2C_6 : TUNER_MOPLL(T/C,ATV)
HDCP EEPROM
S u p p o r t
N o t S u p p o r t
5 V T o l e r a n c e
MODEL_OPT_4
MODEL_OPT_4
C r y s t a l M a t c h i n g T e s t r e s u l t
: 2 7 p F - > 2 0 p F - > 2 4 p F
EAX6509280* : LJ3AC (32/42LT760H-SA)
xxLT760H-UA
1 2 p F C r y s t a l & l o a d c a p .
S O C - > P r o : I d i o m
P r o : I d i o m - > S O C
TUNER -> SOC
P l a c e C l o s e t o M T K 5 3 6 9 ( I C 1 0 5 )
Click on the first or last page to see other 42LT760H-SA (CHASSIS:LJ3AZ) service manuals if exist.