Power Amp Part Check - LG CM4740 Service Manual

AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE

6. POWER AMP PART CHECK

POWER AMP PART CHECK
Check
CN501 Pin10: +12 V
Pin1,2,3: 37 V.
Check IC701, IC702
Pin29, 30, 31, 36, 37, 38 input voltage.
Check IC701, IC702
Pin2: +12 V input.
Check PWM Modulator input
IC701 Pin5, 6, 14, 15 / IC702 Pin5, 6.
Check IC701, IC702
Pin27, 28, 32, 35, 39, 40.
Check output
line coil.
OK
YES
YES
YES
YES
YES
YES
YES
NO
Refer to SMPS troubleshooting.
NO
Check each line resistor output voltage.
NO
3-24
Replace the coil.