Open examination revealed no fracture and components within the machine the appearance of signs of damage, so the amplifier plate completely apart, to check the audio source select the IC PT2314. After power up, check power supply 9V PT2314 ① foot properly, but 25, 272 feet (namely DATA CLK) voltage is 4.2V and 0.4V respectively, obviously 27 foot 0.4V voltage is normal, check toward the CPu down 27 feet. Found a disconnect jumper next to the copper foil. Connected with the Office, everything is normal. This case was due to clock 27 foot line disconnect, PT2314 cannot appear instructions from CPU "failure".avpservice manual download site