LG 42LK450 Service Manual page 67

Trouble shooting guide
8. All Source Audio
Check the TV Speaker Menu
(Menu -> Sound -> TV Speaker)
On
Check AMP IC(IC501) Power
24V, 3.3V, 1.8V.
ok
Check Mstar AUDIO_MASTER_CLK
TP502
ok
Check AMP I2C Line
R506, R507
ok
Check Mstar I2S Output
R503, R504, R505
ok
Check Output Signal P501
1, 2, 3, 4 pin.
ok
Check Connector & P501
ok
Check speaker resistance
and connector damage.
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Only for training and service purposes
Off
Toggle the Menu
No
Check Regulator IC404
No
Replace Mstar(IC101) or Main Board.
No
Check signal line. Or replace Mstar(IC101)
No
Check signal line. Or replace Mstar(IC101)
No
Replace Audio AMP IC(IC501)
No
Replace connector
if found to be damaged.
No
Replace speaker.
LGE Internal Use Only