LG 32LG70 (CHASSIS:LA86B) Service Manual ▷ View online
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(2) TV/CATV
Check TU1 Pin 16 (Video out put).
Can you see the normal signal?
Check the input (Pin 1) of LPF (IC808).
Can you see the normal waveform?
Could you measure voltage of TU1 & IIC
lines? Are they all normal?
You should replace TUNER.
Yes
No
Yes
Yes
Check the input (PinAN16) of BCM355x
(IC100). Measure waveform at C658
because it;s more easy to check.
Can you see the normal waveform?
You should check power line
& IIC lines
No
After checking video signal line & the Power of
LPF you should decide to replace item or not.
No
Check the output (Pin 1) of LPF(IC808).
Can you see the normal waveform?
Yes
Yes
After checking Power of LPF you should decide
to replace item or not.
No
This board has big problem because Main chip
(BCM355x) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM355x or not.
No
(3) AV
Check JK701, JK707.
Can you see the normal waveform?
Check the input (PinAN17, AM19) of BCM355x
(IC100). Measure waveform at C651, C652
because it’s more easy to check.
Can you see the normal waveform?
JK701, JK707 may have problem.
Replace this Jack.
No
This board has big problem because Main chip
(BCM355x) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM355x or not.
Yes
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Yes
(4) Component
Check JK700, JK702.
Can you see the normal waveform?
Check the input and output of BCM355x (IC100).
Measure waveform at C638, C639, C640 and C628,
C629, C630 because it’s more easy to check
Can you see the normal waveform?
JK700, JK702 may have problem.
Replace this Jack.
No
This board has big problem because Main chip
(BCM355x) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM355x or not.
Yes
Yes
(5) RGB_PC
Check JK705.
Can you see the normal waveform?
Check the input(Pin AK16, AN15, AM15, AH16, AJ16 of
BCM355x (IC100). Measure waveform at C635, C636,
C637 and R755, R758 because it’s more easy to check.
Can you see the normal waveform?
JK705 may have problem.
Replace this Jack.
No
This board has big problem because Main chip
(BCM355x) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM355x or not.
Yes
Check DDC communication lines.
(IC601, IC602,IC603, IC701)
Yes
Check the output of PI3HDMI341ATR(IC600).
Can you see the normal waveform?
After checking the Power of this chip, you
should decide to replace this or not.
No
Check the input connect JK600, JK601, JK602, JK708.
Can you see the normal waveform?
Yes
JK600, JK601, JK708 may have problem
Replace this Jack.
No
Check HDCP communication lines. (IC102)
Yes
After checking the Power of this chip, you
should decide to replace this or not.
No
This board has big problem because Main chip
(BCM355x) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM355x or not.
No
(6) HDMI
2. AUDIO
(1) Audio path
- 19 -
AT/NT
Tuner
BCM355x
SIF
IF_VSB/QAM
SD_SIF1
EDSAFE_IF_N
EDSAFE_IF_P
PI3HDMI341ART
HDMI
HDMI_RX_0_CLK_N
HDMI_RX_0_CLK_P
HDMI_RX_0_DATA0_N
HDMI_RX_0_DATA0_P
HDMI_RX_0_DATA1_N
HDMI_RX_0_DATA1_P
HDMI_RX_0_DATA2_N
HDMI_RX_0_DATA2_P
CS5345-CQZR
(Audio SW)
MC33078
(AMP)
CS5340
(A/D)
AV1
AV2
COMP1
COMP2
RGB
I2S_CLK_IN
I2S_DATA_IN
I2S_LR_IN
I2S_CLK_OUT
I2S_DATA_OUT
I2S_LR_OUT
NTP3000
(D-AMP)
AUD_SPDIF
buffer
SPDIF out
Coaxial out
AUD_LEFT_P
AUD_RIGHT_P
MNT out
TMDS141
HDMI4
(2) TV/CATC - Audio (In)
- 20 -
Check TU1 Pin 14 (SIF).
Can you see the normal signal?
Check the input (Pin AN23) of BCM355x (IC808).
Can you see the normal waveform?
Could you measure voltage of TU1 & IIC
lines? Are they all normal?
You should replace TUNER.
Yes
No
Yes
You should check power line
& IIC lines.
No
After checking audio signal line, you
should decide to replace item or not.
No
(3) AV/ Component/ RGB-PC - Audio (In)
Check the input (Pin 7,8,9,10,11,12,21,22,26,27) of
CS5345(IC500). Can you see the normal waveform?
Yes
Check the input (Pin INPUT1-,INPUT2-) of MC33078DR2G
(IC504).Can you see the normal waveform?
After checking audio signal line, you should
decide to replace item or not.
No
Check JK701, JK707, JK700, JK702, JK703.
Can you see the normal waveform?
Yes
JK701, JK707, JK700, JK702, JK703 may
have problem. Replace this Jack.
No
Check the Output (Pin LOUT1,ROUT1) of CS5345
(IC500). Can you see the normal waveform?
Yes
After checking the Power of this chip, you
should decide to replace this or not.
No
After checking audio signal line, you should
decide to replace item or not.
No
Check the Output (Pin OUTPUT1,OUTPUT2) of MC33078DR2G
(IC504).Can you see the normal waveform?
Yes
Check the Output (Pin SDOUT,SCLK,LRCK) of CS5340
(IC502).Can you see the normal waveform?
After checking the Power of this chip, you
should decide to replace this or not.
No
Yes
Check the input (Pin AINL,AINR) of CS5340(IC502).
Can you see the normal waveform?
Yes
After checking audio signal line, you should
decide to replace item or not.
No
After checking the Power & MLCK & reset of this
chip, you should decide to replace this or not.
No
Check the input (Pin AH24,AJ24,AK24) of BCM355x (IC100).
Measure waveform at R559,R560,R561 because it’s more
easy to check.Can you see the normal waveform?
Yes
After checking audio signal line, you should
decide to replace item or not.
No
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