Sound (Optical) - LG LAS350B Service Manual

5. NO SOUND (OPTICAL)
5-1. Solution
Replace IC401 on MAIN board.
5-2. How to troubleshoot (Countermeasure)
1) Please check 3.3 V of 3.3 VA at L505 in USB board
If you can check 3.3 V, please confirm OPT_DET signal (R428) in MAIN board when optical mode.
2) In spite of process 1), set has abnormal output, then replace IC401.
5-3. Service hint (Any picture / Remark)
ONE POINT REPAIR GUIDE
CON502
D503
1 KDS226
P_R
2
P_L
3
P_DET
4
P_GND
5
SPDIF
6 R503
GND
0R
7
5V
8 L506
0R
D+
R504
9 L507
0R
D-
0R
10
GND
L505 L505
< USB board bottom view >
< MAIN board top view >
9
8
L501 600RH 4
L502 600RH
5
L503 600RH 7
6
L504
600RH 1 2 3
R317
0R
C316
R316 NC
10NF
C504 R318
100R 100R
1 OUT
2 GND
L505 600RH
3 VCC
L508
600RH
C505 C317
C506
10PF 100PF
100NF
IC401 IC401
3-6
R
L
JK504
JK502
R428 R428