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2016-10-10 by yarreau@...
I am trying to get this old beast up and running. The issue is the distorted audio out. The sound file is with volume at 1/2 the full level. Any idea where I would start to troubleshoot? I do not have a scope so thats out of the question. I can replace caps if that is the consensus.
Thanks,
Bill
2016-10-10 by Paul D. DeRocco
> From: Bill <yarreau@...>Trying to fix things by changing things that might be bad is a poor way to do it, but at least the chips are socketed, so I'd start there first. I'd suspect the chips on the output board, or the 4053's on the main board that contain the output switches (Zx08). You might also try removing one 3372 VCF/VCA chip (Zx09) at a time, to see if one of them is corrupting the output; if that eliminates the distortion (at the cost of one channel), then you can arrange to buy an (expensive) replacement.
>
> I am trying to get this old beast up and running. The issue
> is the distorted audio out. The sound file is with volume at
> 1/2 the full level. Any idea where I would start to
> troubleshoot? I do not have a scope so thats out of the
> question. I can replace caps if that is the consensus.
2016-10-10 by Florian Anwander
as Paul already explained: blind replacing is not recommended (would you start pulling your teeth, when you have a head ache - hoping that one of the teeth might be the cause...?).I am trying to get this old beast up and running. The issue is the distorted audio out. The sound file is with volume at 1/2 the full level. Any idea where I would start to troubleshoot? I do not have a scope so thats out of the question. I can replace caps if that is the consensus.
If you don't have a scope, then I recommend to use a test prod connected via a 100nF capacitor to a channel of your mixer. Connect also the normal output to your mixer, to have a groundconnection. You don't have to listen to the normal output.
Now you may trace the audio signal acoustically from the VCOs to the output.
Turn the volume only as loud as required, and perhaps lower the high frequencies of this measuring channel to protect the tweeters of your loudspeakers.
Florian
2016-10-11 by yarreau
On Oct 10, 2016, at 2:32 PM, 'Paul D. DeRocco' pderocco@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:> From: Bill <yarreau@...>
>
> I am trying to get this old beast up and running. The issue
> is the distorted audio out. The sound file is with volume at
> 1/2 the full level. Any idea where I would start to
> troubleshoot? I do not have a scope so thats out of the
> question. I can replace caps if that is the consensus.
Trying to fix things by changing things that might be bad is a poor way to do it, but at least the chips are socketed, so I'd start there first. I'd suspect the chips on the output board, or the 4053's on the main board that contain the output switches (Zx08). You might also try removing one 3372 VCF/VCA chip (Zx09) at a time, to see if one of them is corrupting the output; if that eliminates the distortion (at the cost of one channel), then you can arrange to buy an (expensive) replacement.
--
Ciao, Paul D. DeRocco
Paul mailto:pderocco@...