LG OM7550 - Speaker no Audio

3-8
ONE POINT REPAIR GUIDE
7. SPEAKER NO AUDIO
Speaker No Audio
7-1. AMP IC (IC700, IC701, IC705)
7-1-1. Solution
Replace IC700, IC701, IC705 on MAIN board.
7-1-2. 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).
CSD has about 5 V on normal state.
When AMP has problem, CSD is LOW state or keep change LOW to HIGH.
7-1-3. Service hint (Any picture / Remark)
< MAIN board top view >
< MAIN board top view > < MAIN - AMP circuit >
CN110
CN110
pin1, 2 : +66 V
pin1, 2 : +66 V
pin3, 4 : PGND
pin3, 4 : PGND
pin5, 6 : -66 V
pin5, 6 : -66 V
pin5 of ICs
pin5 of ICs


CSD
CSD