LG SN4A - Page 39

3-10
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ONE POINT REPAIR GUIDE
NO SOUND
2-2. OPTICAL
2-2-1. Solution
Replace MAIN board.
2-2-2. How to troubleshoot (Countermeasure)
1) Please check 3.3 VA at R209.
2) If 3.3 VA is ok, please check OPT_IN signal (C208) when OPTICAL mode.
3) If signal is abnormal, replace MAIN board.
2-2-3. Service hint (Any picture / Remark)
< MAIN board top view >
OPTICAL JACK,96KHz
3.3VA
JK202
1
OUT
2
GND
3
VCC
R209
82
R202 100
C208
15pF
R201
560
DGND DGND
OPT_IN
OPT_DET
C207
1uF
C224
100pF
MPEG
MICOM
OPTICAL
R209
R209
C208
C208
JK202
JK202