LG 42LV375H Service Manual page 19

10. RS-232C(DSUB 9P) function Trouble Shooting guide
- Ext Power Out
Is the 5 V or 12 V out "Yes" on
Installation menu?
Y
Check the IC1509(12 V),
IC1508(5 V).
Y
Check the Q1506
(EXT_PWR_DET) line.
Y
Replace Main board.
- IR Out
Check the IR Waveform of
Q2401, Q2402.
Y
Check the IC702.
Y
Check the JK1100 4 Pin
connection.
11. Commercial Function Trouble Shooting guide
- Front Clock
Check the Clock display setting
"Yes" on Installation menu.
Y
Check the "Time" setting on
user menu.
Y
Is the clock cable normal?
Y
Check the +5 V_ST Line.
Y
Check the IC705.
Y
Check the LED Clock Ass'y.
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Only for training and service purposes
N
Set "Yes" on Installation menu.
N
Replace IC1509, IC1508.
N
Replace Q1506 part.
N
Replace Q2401, Q2402.
N
Replace IC702.
N
Set "Yes" on Installation menu.
N
Set Time/Clock on user menu.
N
Check the clock cable.
N
Replace the IC706.
N
Replace the IC705
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