LG SJ8 - Protection Error

3-13
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Only for training and service purposes.
ONE POINT REPAIR GUIDE
3. PROTECTION ERROR
No display or No Sound.
3-1. D(DC) PROTECTION
3-1-1. Solution
Replace AMP board.
3-1-2. How to troubleshoot (Countermeasure)
1) Check DC voltage of speaker out FL+/-, TWL+/- (CN701 pin1, 2, 3, 4), FR+/-, TWR+/- (CN702 pin1, 2, 4, 5).
2) Check capacitor crack, cold solder of OP-AMP out (C7X6, C7X7, C7Y3, C7C5).
3) If OP_AMP out is OK and speaker out (FL+/-, FR+/-, TWL+/-, TWR+/-) has DC voltage, replace AMP board.
3-1-3. Service hint (Any picture / Remark)
< AMP board top view >
CN701
CN701
CN702
CN702