LG 42LN541C Service Manual page 17

6. All Source Audio
Check the TV Speaker Menu
(Menu -> Audio -> TV Speaker)
On
Check AMP IC(IC501) Power
24V, 3.3V
ok
Check Mstar AUDIO_MASTER_CLK
R148
ok
Check AMP I2C Line
R503, R504
ok
Check signal line, L505, L506
ok
Check Output Signal P501
1, 2, 3, 4 pin.
ok
Check Connector & P501
ok
Check speaker resistance
and connector damage.
7. Digital/Analog TV Audio
Check RF Cable & Signal
ok
Check Tuner 3.3V Power
L1003
ok
Check Tuner 1.8V Power
IC1001 2 pin : 1.8V
ok
Check IF_P/N Signal
TU1002 6 Pin
ok
Follow procedure
'7. All source audio'
trouble shooting guide.
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Only for training and service purposes
Off
Toggle the Menu
No
Replace Amp IC(IC501)
No
Replace Mstar(IC101) or Main Board.
No
Check signal line. Or replace Mstar(IC101)
No
Replace Audio AMP IC(IC501)
No
Replace C535, C537, C538, R516, R517
No
Replace connector
if found to be damaged.
No
Replace speaker.
No
Replace L1003
No
Replace IC1001
No
Bad Tuner. Replace Tuner.
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