LG CM2760 Service Manual page 21

PROTECTION
4-2. S(SHUT DOWN) PROTECTION
4-2-1. Solution
Replace IC301(AMP IC) on MAIN board.
4-2-2. How to troubleshoot (Countermeasure)
1) Press the power button, the display is normal, no sound output. (D Protection or S Protection)
2) Check PVDD Voltage. (27 V)
- If PVDD abnormal Voltage, Refer to SMPS Board repair guide.
3) Check GVDD, VDD Voltage(12 V) of IC301 pin1, 22, 23, 44.
- If 12 V system abnormal Voltage, Refer to 12 V no power repair guide.
4) Check impedance (4 Ω) of speaker unit .
- If Impedance of speaker unit has 1 Ω under, replace speaker unit .
5) If check point 2, 3, 4 is ok, replace IC301(AMP IC) on MAIN board.
4-2-3. Service hint (Any picture/ Remark)
ONE POINT REPAIR GUIDE
< MAIN board top view >
IC301 (AMP IC) IC301 (AMP IC)
3-6