Trying to repair Yamaha RX-V473, service manual is at elektrotanya.com/yamaha_rx-v473_htr-4065_sm.pdf/download.html,
On all inputs, all active speaker channels, there is a static-y white noise (a bit like the test tones, but quieter) with distorted audio, except on analogue inputs in Direct mode, when it sounds fine. Digital inputs in Direct mode still have the static noise and distorted audio.
When no input connected, analogue inputs just have the static noise; digital inputs (and tuner, USB etc) are silent. I've done factory reset, firmware update and basic checking of power supplies and regulator voltages, all OK. Also replaced the HDMI board's regulator electrolytic capacitors just in case.
I think that the analog inputs go through DIR/ADC, then to DSP, then to DAC and finally to audio amplifier, except in Direct mode where they presumably bypass ADC, DSP and DAC.
Digital inputs go to through DIR (no ADC needed), then to DSP, then to DAC and finally to audio amplifier. Direct mode presumably just bypasses DSP, as DAC would still be needed.
The DSP functions (sound fields) do appear to work, with correct speaker configuration (and shown on the display), but with the static / distortion on all active speaker channels.
So I'm thinking the problem is likely to be with the DAC or DSP chip, but not sure how to test or check this, or determine which one.
Any help or insights greatly appreciated.
TIA, Jon.
On all inputs, all active speaker channels, there is a static-y white noise (a bit like the test tones, but quieter) with distorted audio, except on analogue inputs in Direct mode, when it sounds fine. Digital inputs in Direct mode still have the static noise and distorted audio.
When no input connected, analogue inputs just have the static noise; digital inputs (and tuner, USB etc) are silent. I've done factory reset, firmware update and basic checking of power supplies and regulator voltages, all OK. Also replaced the HDMI board's regulator electrolytic capacitors just in case.
I think that the analog inputs go through DIR/ADC, then to DSP, then to DAC and finally to audio amplifier, except in Direct mode where they presumably bypass ADC, DSP and DAC.
Digital inputs go to through DIR (no ADC needed), then to DSP, then to DAC and finally to audio amplifier. Direct mode presumably just bypasses DSP, as DAC would still be needed.
The DSP functions (sound fields) do appear to work, with correct speaker configuration (and shown on the display), but with the static / distortion on all active speaker channels.
So I'm thinking the problem is likely to be with the DAC or DSP chip, but not sure how to test or check this, or determine which one.
Any help or insights greatly appreciated.
TIA, Jon.
Fixed! Thinking about what was happening, it seemed to me that since the volume control, DIR, ADC and DSP all seemed to be working, the problem was most likely in the DAC, especially since Direct Mode, 2CH Stereo and Straight for analogue inputs worked fine - I assume that these unprocessed analogue signals would bypass ADC/DAC.
Anyway, I replaced the DAC chip with a new one from Aliexpress (around NZ$11), fired it up, and everything's working great now! No static, just nice clean sound on all channels and for all DSP sound fields.
Anyway, I replaced the DAC chip with a new one from Aliexpress (around NZ$11), fired it up, and everything's working great now! No static, just nice clean sound on all channels and for all DSP sound fields.