LG CJS98F - Speaker no Audio

3-18
ONE POINT REPAIR GUIDE
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)
< MAIN board top view >
< AMP IC > < AMP IC >
CN800
CN800
pin1, 2 : +66 V
pin1, 2 : +66 V
pin3, 4 : PGND
pin3, 4 : PGND
pin5, 6 : -66 V
pin5, 6 : -66 V
pin5 of IC
pin5 of IC


CSD
CSD