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Hitachi VT-M757E (DH) video appeared like sound on small, silent failure repair method to record TV programs

Time£º2014-07-20 09:24:43  Source£ºNetwork  Author£ºUnknown  Clicks£º1180
  

By the phenomenon analysis, fault should be in the audio playback system. In the condition of video reproduction, inject body induction signal from the audio playback head, but the small voice in the speaker. The brand video recorder of most of the failure are almost electrolytic capacitor. So in a 4.7 & mICro; F / 16 v electrolytic capacitor, follow the audio signal, on both ends of the signal coupling capacitance of the capacitor parallel individually, when in parallel to the audio output capacitance C482 (4.7 (including 35 v/F) at both ends, the sound suddenly increase to normal. Remove the capacitance measurement, found has completely without the capacity. After the replacement troubleshooting. tVVservice manual download site
So why C482 failure can make the video reproduction of sound small and lead to video at the same time silent? By the local circuit, the audio playback in the condition of video, audio signal after C482 output part and the R402 from record/audio processing block IC401 (XRA7767A) 20 feet into the internal REC/AMP switch, selected from 25 feet after the output, then the C407, R408 into record/put heads were recorded. Obviously, when C482 capacity loss, cannot stay recorded audio signal into record/put heads, lead to record the show are silent.tVVservice manual download site