LG SJ8 Service Manual page 44

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 FB201.
2) If 3.3 VA is OK, please check OPT_IN signal(R203) when optical mode.
3) If signal is abnormal, replace MAIN Board.
2-2-3. Service hint (Any picture / Remark)
ONE POINT REPAIR GUIDE
 
< MAIN board top view >
 
JK201 JK201
   
3-9
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only for training and service purposes.