LG 32LT670H-UA Service Manual page 19

Composite Video Trouble Shooting guide
Check input signal format.
Is it supported?
Y
Check AC cable for damage
For damage or open conductor
Y
Check JK1700
Can you see the normal waveform?
Y
Check the input of Mstar(IC101).
Measure waveform at C217 because it's more easy to check.
Can you see the normal waveform?
Y
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.
HDMI Video Trouble Shooting guide
Check input signal format.
Is it supported?
Y
Check AC cable for damage
For damage or open conductor
Y
Check JK800/JK801/JK802
Can you see the normal waveform?
Y
Check HDCP key NVRAM(IC103)
Power & I2C signal
Y
Check the input of Mstar(IC101).
Measure waveform at R4024, R4025 because it's more easy to check.
Can you see the normal waveform?
Y
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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Only for training and service purposes
N
Replace JK1700
N
Replace JK800, JK801, JK802
N
Replace IC103
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