Try to input the AV signal commissioning, everything is normal, judge fault parts in the sound signal processing circuit. The machine sound signal processing circuit as shown in the appended drawings, IC101 (M52034SP) {} 17 feet output video signal, the X202 (6.5 MHz and 233 (6.0 MHz) filter to select the 6.5 MHz and 6.0 MHz from {12} feet input sound signal, through the internal limiting amplifier and FM detector, the output audio signal from {10} feet.} {9 feet external FM detector coil L228. In addition, the CPU {4} the feet, through the Q102, D201, D203, D204 PAL I/D conversion of audio formats. Measuring IC101 {12} feet normal voltage (V) 3, {10} feet between 1.6 ~ 2.4 V voltage changes, and the normal value should be 2.8 V, IC101 {9} feet voltage from 3.8 V to 4.4 V, and the normal value should be 3.2 V or so. Key check IC101 {9} feet peripheral components, found C209 (30 pf adjustable capacitors) has serious leakage. With a capacity of 17 pf ceramics capacitors instead of sound back to normal.H2Qservice manual download site