LG LAS454B - D(DC) Protection

3-8
ONE POINT REPAIR GUIDE
7. D(DC) PROTECTION
7-1. Solution
Replace IC703 (AMP IC) on MAIN board.
7-2. How to troubleshoot (Countermeasure)
1) After MAIN SET power off, check Red LED blink at intervals of 1 sec. (D Protection or S Protection)
2) Turn MAIN SET power on again.
3) Check DC Voltage of speaker out FL+/- (CN703 pin1, 2), FR+/- (CN704 pin1, 3).
4) Check resistor crack, cold solder of PWM IC out (R751, R753, R759, R761).
5) If PWM IC out is ok and speaker out (FL+/-, FR+/-) has DC Voltage,
Replace IC703 (AMP IC) on MAIN bottom board.
7-3. Service hint (Any picture / Remark)
< MAIN board top view >
< MAIN board bottom view >
CN703
CN703
CN704
CN704
IC701 (PWM IC)
IC701 (PWM IC)
IC703 (AMP IC)
IC703 (AMP IC)
R761, R759
R761, R759
R753, R751
R753, R751