Electricity boot, observed the machine image is normal, just in the vocal tract, analysis considered voice processing circuit has a problem. Open the machine cover, remove the AV board, check the sound track of jack J8004 contact resistance, normal. Check jack resistor, capacitor in the peripheral circuit also is normal. This machine by the audio decoder IC4001 (MN67730MH) 48 of the 49 feet, 55, the output of the digital audio signal, via IC4211 (PCM1710) after conversion, / a output from 13 feet, 16 feet, then through connectors P24101 5 feet, 26 feet to IC4221 (NJM4580M) 2 feet and 6 feet after amplification processing output from jack. Use oscilloscope to observe P24101 5 feet with normal audio signal waveform, IC4221 1 foot, 2 feet waveform is also normal, as shown in chart 2, but when measuring its six or seven feet waveform, found the feet abnormal waveform. Examine IC4221 6 or 7 feet peripheral components, found the capacitance C4243 failure, replace a 16 v / 47 u F electrolytic capacitor, electricity boot, troubleshooting.JWnservice manual download site