LG 32LD340H Service Manual page 45

AV Video Trouble shooting guide
Check input signal format.
Is it supported?
YES
Check AC cable for damage
For damage or open conductor
YES
Check JK3100
Can you see the normal waveform?
YES
Check the input of Mstar(IC101).
Measure waveform at C227 because it's more easy to check.
Can you see the normal waveform?
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Only for training and service purposes
NO
JK3100 may have problem. Replace this Jack.
YES
This board has big problem because Main chip (Mstar) have some troubles.
After checking thoroughly all path once again, You should decide to replace Mstar or not.
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