LG SH4 - B(Burnt) Protection

3-11
ONE POINT REPAIR GUIDE
9. D(DC) PROTECTION
9-1. Solution
Replace IC702, IC703 (AMP IC) on MAIN board.
9-2. 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_P/N, TWL_P/N (CN703 pin1, 2, 3, 4) and FR_P/N, TWR_P/N
(CN704 pin1, 2, 4, 5).
4) Check resistor crack, cold solder of PWM IC out (R710 ~ R717).
5) If PWM IC out is ok and speaker out (FL+/-, FR+/-, TWL+/-, TWR+/-) has DC voltage,
replace IC702, IC703 (AMP IC) on MAIN bottom board.
9-3. Service hint (Any picture / Remark)
< MAIN board top view >
< MAIN board bottom view >
CN703
CN703
CN704
CN704
IC701
IC701
(PWM IC)
(PWM IC)
R710 ~ R717
R710 ~ R717
IC703
IC703
IC702
IC702