LG 42LN541C Service Manual page 18

8. AV/RGB Audio
Check AV Cable for damage
for damage or open conductor
ok
Check JK701 Signal Line
R706,R707
ok
Follow procedure
'7. All source audio'
trouble shooting guide.
9. External Speaker Out
Check AMP IC(IC901) Power 24V
L902
ok
Check Mstar External AUDIO output
R201, R202
ok
Check AMP IC(IC901) Mute High
R1924, 4pin
ok
Check AMP IC(IC1800) Output
2,12,14, 24 Pin
ok
Check Output Signal JK902
4,5 pin.
ok
Check JK902
ok
Check External Speaker
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Only for training and service purposes
No
Replace Jack
No
Replace L902
No
Replace Mstar(IC101) or Main Board.
No
Check signal line. Or replace Mstar(IC101)
No
replace AMP IC(IC901)
No
Replace Phone Jack(JK902)
No
Replace Phone Jack
if found to be damaged.
No
Replace External speaker.
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LGE Internal Use Only