LG 42LB7DF (CHASSIS:LJ81A) Service Manual ▷ View online
- 25 -
Check RF Cable
Check TP Clock, Data, Sync
R925 (38.1MHz), R804, R803
Maybe Tuner(TU800) has problems
Check BCM3553 Output TP Clock,
Data, Sync
R153, R155, R152
Check BCM7412 Clock,
Hsync
, Vsync
R1088 (
Typ
. 74.25MHz), R1087, R1086
Y
Y
N
Check Tuner 5V Power
IC810 #3 Pin
Replace IC810
Y
N
Y
Maybe BCM3553(IC100) has problems
N
Maybe BCM7412(IC1000) has problems
N
Check PLD Clock,
Hsync
, Vsync
R1102 (
Typ
. 74.25MHz), R1100, R1101
Y
Redownload
PLD file or replace
N
Maybe BCM3553(IC100) has problems
Y
Check D805 color
Bad Tuner. Replace Tuner.
None
red
Check BCM7412 Input Clock
R107 (27MHz)
Replace it
N
Y
TROUBLESHOOTING
3. Digital TV Video
3-2. Troubleshooting
- 26 -
Flash
(32MB)
DDR1(128MB)
(16Mx16x4)
DDR1(128MB)
(16Mx16x4)
TEA6420
Audio
SW
MTV416
(M
icom
)
NTP3000
(Digital AMP)
64Bit I/F
RGB-PC
HDMI
1/2/3
COMP 1
COMP 2
AV1
AV2
RGB-PC
I2S
MCLK
Digital out
COMP1
COMP2
AV1
AV2
BCM7412
(MPEG4
Decoder)
Analog
/Digital
Tuner
TC90512
DVI
I2S
SIF
SPDIF Out
CVBS
CVBS/Y/C
Y/
Cb
/Cr
R/G/B
DDR1
(64MB)
CS5340
L/R
Serial TP
20bits
12bit YC 4:2:2
NIM TUNER
TMDS_RX+-
EPM240F
MNT out (Audio Only)
TMDS341A
(3x1,S/W)
CVBS/Y/C
MC33078
(AMP)
L/R
RS232
RX/TX
DVI
4:2:2 20bit YC
Full HD(1080P)
WXGA(768P)
RF
Switch
DM1/DP1
Serial
TP
74HC04
SPDIF Out
(Coaxial)
Video
Front
End
Dual
HDMI
Rx
HD/SD
Video
Encoder
Audio
DSP
USB2.0
PKT
HSX
PCI/
EBI
HD-DVI
IB0
Parse2
RSBUF
XCBUF
RMX0
BCM3553
Local KEY
24C16
74LVC14APW
X-tal(54M)
Reset
KIA7029
NVRAM
I2C
TROUBLESHOOTING
4. Analog TV Video
4-1. Block Diagram of Troubleshooting
- 27 -
Check RF Cable
Check CVBS signal
TU800 #17 Pin
Maybe Tuner(TU800) has problems
Check CVBS signal
IC808 #8 Pin
Check CVBS signal
C658
Y
Y
N
Check Tuner 5V Power
IC810 #3 Pin
Replace it
Y
N
Y
Replace IC808 or check L800 5V power
N
Replace it
N
Y
Maybe BCM3553(IC100) has problems
TROUBLESHOOTING
4. Analog TV Video
4-2. Troubleshooting
- 28 -
Flash
(32MB)
DDR1(128MB)
(16Mx16x4)
DDR1(128MB)
(16Mx16x4)
TEA6420
Audio
SW
MTV416
(M
icom
)
NTP3000
(Digital AMP)
64Bit I/F
RGB-PC
HDMI
1/2/3
COMP 1
COMP 2
AV1
AV2
RGB-PC
I2S
MCLK
Digital out
COMP1
COMP2
AV1
AV2
BCM7412
(MPEG4
Decoder)
Analog
/Digital
Tuner
TC90512
DVI
I2S
SIF
SPDIF Out
CVBS
CVBS/Y/C
Y/
Cb
/Cr
R/G/B
DDR1
(64MB)
CS5340
L/R
Serial TP
20bits
12bit YC 4:2:2
NIM TUNER
TMDS_RX+-
EPM240F
MNT out (Audio Only)
TMDS341A
(3x1,S/W)
CVBS/Y/C
MC33078
(AMP)
L/R
RS232
RX/TX
DVI
4:2:2 20bit YC
Full HD(1080P)
WXGA(768P)
RF
Switch
DM1/DP1
Serial
TP
74HC04
SPDIF Out
(Coaxial)
Video
Front
End
Dual
HDMI
Rx
HD/SD
Video
Encoder
Audio
DSP
USB2.0
PKT
HSX
PCI/
EBI
HD-DVI
IB0
Parse2
RSBUF
XCBUF
RMX0
BCM3553
Local KEY
24C16
74LVC14APW
X-tal(54M)
Reset
KIA7029
NVRAM
I2C
TROUBLESHOOTING
5. Component Video
5-1. Block Diagram of Troubleshooting
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