Speaker No Audio - LG CJ87 Service Manual

8. SPEAKER NO AUDIO

Speaker no audio.
8-1. AMP IC (IC700 ~ IC702, IC800 ~ IC802)
8-1-1. Solution
Replace IC700 ~ IC702, IC800 ~ IC802 on MAIN board.
8-1-2. How to troubleshoot (Countermeasure)
1) Check supply voltage of AMP(CN800) & 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.
8-1-3. Service hint (Any picture/ Remark)
pin5 of IC pin5 of IC   CSD
< AMP IC >
ONE POINT REPAIR GUIDE
CSD
< MAIN board top view >
pin1, 2 : +66 V pin1, 2 : +66 V
pin3, 4 : PGND pin3, 4 : PGND
pin5, 6 : -66 V pin5, 6 : -66 V
3-18
CN800 CN800
< AMP IC >