LG 37LC7D - Page 38

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- TV/CATV doesn't display
Check TU4001 Pin9(Video output)
Can you see the normal signal?
Check the input(Pin63) of AV
switch(IC5003).
Can you see the normal waveform?
Check the output(Pin56) of AV
switch(IC5003).
Can you see the normal waveform?
Check the input(Pin1) of LPF(IC4006).
Can you see the normal waveform?
YES
YES YES
NO
Could you measure voltage of TU4001 &
IIC lines?
Are they all normal?
Check the output(Pin8) of LPF(IC4006).
Can you see the normal waveform?
YES
Check the input(PinH26) of
BCM3550(IC4006).
Measure waveform at C1010 because its
more easy to check.
Can you see the normal waveform?
YES
NO
You should check power line
& IIC lines.
YES
You should replace TUNER.
NO
After checking the Power of AV switch you
should decide to replace AV switch or not.
NO
After checking the Power of AV switch you
should decide to replace AV switch or not.
NO
After checking the Power of LPF you should
decide to replace LPF or not.
NO
After checking the Power of LPF you should
decide to replace LPF or not.
YEX
This board has big problem because Main
chip(BCM3550) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM3550 or not.