LG 42LV375H Service Manual page 15

3. Analog RF Video Trouble Shooting guide
Check RF Cable.
(TU2701 RF Cable)
Y
Check TU2701 Pin 11(Video
out put). Can you see the
normal signal?
Y
Check the input(PinAD9) of
BCM3556(IC100).
Measure waveform at
C110 or R2112 because it's
more easy to check.
Can you see the normal
waveform?
Y
This board has big problem
because Main chip(BCM3556)
have some troubles.
After checking thoroughly all
path once again, You should
decide to replace BCM3556 or
not.
4. Digital RF Trouble Shooting guide
Check RF Cable.
MPI to TU2701 RF Cable
Y
Check TU2701 power
Pin 16 (2.5 V), Pin 13(1.2 V)
Y
Check IIC signal TU2701
Pin 17, 18
Y
Check FE_TS_DATA[0].
Y
Check Power of IC2802 (3.3 V /
1.8 V / 5 V).
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Only for training and service purposes
N
You should replace Cable.
Could you measure voltage of
N
TU2701 & IIC lines?
Are they all normal?
You should replace TUNER.
N
You should replace Cable.
N
Check IC2701.
N
Check IIC Line
SCL2_3.3 V/SDA3_3.3 V
N
Replace TU2701.
N
Check IC2800/ IC2803.
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N
Y
N
N
You should check power line &
IIC line.
Replace IC2701.
Check IC2800/ IC2803.
LGE Internal Use Only