LG OM4560 Service Manual page 34

PROTECTION
6-2. S(Shut down) Protection
6-2-1. Solution
Replace IC701(AMP IC) on MAIN top board.
6-2-2. How to troubleshoot (Countermeasure)
1) After main set power off, check red LED blink at intervals of 1 second. (D Protection or S Protection)
2) Turn main set power on again.
3) Check PVDD voltage (34 V) of CN600 pin4, 5, 6.
- If PVDD voltage has 25 V under, refer to SMPS board repair guide.
4) Check GVDD, VDD voltage (12 V) of IC701 pin1, 22.
- If GVDD, VDD voltage has 8.5 V under, refer to 12V no power repair guide.
5) Check impedance (3 ohm) of speaker unit.
- If Impedance of speaker unit has 1 ohm under, replace speaker unit.
6) If check point 3, 4, 5 is ok, replace IC701(AMP IC) on MAIN top board
6-2-3. Service hint (Any picture/ Remark)
CN600 CN600
ONE POINT REPAIR GUIDE
< Main board top view >
3-17
IC701 (AMP IC) IC701 (AMP IC)