Speaker No Audio - LG CM9550 Service Manual

9. SPEAKER NO AUDIO

Speaker No Audio
9-1. AMP IC
9-1-1. Solution
Please check and replace IC700 ~ IC705 on MAIN board.
9-1-2. How to troubleshoot (Countermeasure)
1) Check supply voltage of AMP(CN110) & PWM signal
Normal Supply voltage and signal  Check AMP IC.
Poor supply voltage  Check SMPS Assy.
Poor signal  Check PWM IC.
2) Check CSD of FET driver IC (IRS2092 : EAN60778301).
CSD has about 5 V on normal state.
When AMP has problem, CSD is LOW state or keep change LOW to HIGH.
9-1-3. Service hint (Any picture / Remark)
ONE POINT REPAIR GUIDE
# 5 P IN of IC → CSD
3-24
C N 110 P IN1, 2 : - 66 V
P IN3, 4 : P GND
P IN5, 6 : +66 V