LG 55LS675H (CHASSIS:LA2AG) Service Manual ▷ View online
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7. RGB-PC Video Trouble shooting guide
Check P900
Can you see the normal waveform?
NO
P900 may have problem. Replace this Jack.
Check the input of Mstar(IC101).
Measure waveform at R4042, R4025
because it’s more easy to check.
Can you see the normal waveform?
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.
YES
Check input signal format.
Is it supported?
YES
Check AC cable for damage
For damage or open conductor
YES
8. Analog RF Audio Trouble shooting guide
Check RF Cable & Signal
Check Audio AMP output
L503,L504,L505,L506
Y
Check TU3001 Pin1 (SIF Output)
Can you see the normal signal?
Y
Could you measure voltage of TU3001& IIC lines?
Are they all normal?
N
You should check
power line & IIC lines.
N
You should replace TUNER.
Y
Check IC501
Y
Replace IC501
N
Replace L503,L504,L505,L506
N
Check the input of Mstar (IC101).
Measure waveform at C250
because it’s more easy to check.
Can you see the normal waveform?
Y
After checking audio signal line,
you should decide to replace item or not.
N
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9. AV/Component/RGB-PC Audio(in)Trouble shooting guide
Check input signal format.
Is it supported?
Check JK1700, P900
Can you see the normal
waveform?
Replace JK1700, P900
Y
N
Check AC cable for damage
For damage or open conductor
Y
Y
Check the input of Mstar(IC101).
Measure waveform at C236, C237, C244, C245 because it’s more easy to check.
Can you see the normal waveform?
Y
Check Audio AMP output
L503,L504,L505,L506
Y
Replace L503,L504,L505,L506
N
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.
10. HDMI Audio(in) Trouble shooting guide
Check input signal format.
Is it supported?
Check JK800/JK801/JK802
Can you see the normal
waveform?
Replace JK800/JK801/JK802
Y
N
Check AC cable for damage
For damage or open conductor
Y
Y
Check Audio AMP output
L503,L504,L505,L506
Y
Replace L503,L504,L505,L506
N
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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11. Audio out Trouble shooting guide
Check the output of Mstar(IC101).
Measure waveform at R148, R503, R504.
because it’s more easy to check.
Can you see the normal signal?
YES
NO
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.
Check Audio AMP output L503,L504,L505,L506
Can you see the normal waveform?
NO
YES
After checking the Power & I2C & Reset of this chip,
you should decide to replace this or not.
Check the speaker output wafer P501.
Can you see the normal waveform?
NO
YES
After checking audio signal line,
you should decide to replace item or not.
Check the connector & Speaker
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BLOCK DIAGRAM
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