I don't own a D50 and have not seen the D50 service manual (there doesn't seem to be a copy floating around online), so don't trust this to be correct or even relevant, it's just my best guess.
There may be an MSB adjustment for the D50's DAC (I know the JD-800 has this). If this is off, there will be a discontinuity at every zero-crossing, producing distortion at any signal level. There will be a trimmer for this (if it's adjustable), but you shouldn't just go arbitrarily turning trimmers to find it.
You may want to record the D50's output to your computer so you can observe the waveform and get a better idea of what's going on.
________________________________
> To: vintagesynthrepair@yahoogroups.com
> From: adam@brinkmannmusic.com
> Date: Thu, 25 Sep 2008 12:32:45 -0500
> Subject: [vintagesynthrepair] Roland D-50 Output Distorted
>
>
> Anyone point me in right direction to repair distorted output on all
> outs- headphone, L & R. Distortion lasts until sound decay stops.
>
> Cleaned contacts and surface of output board. I'm not a tech, but a
> player, but this seems like should be a simple fix.
>
> Don't have schematics and can't find any previous posts on this
> problem. TIA!
>
>
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Message
Re: [vintagesynthrepair] Roland D-50 Output Distorted
2008-09-26 by Brinkmann Music
It got a little worse turned all the way counter clock wise, no change turned all the way clockwise.
The distortion is a constant level-not related to volume slider position. As soon as you turn up output from output edit page, you hear it. It is fairly low, but very, very noticeable on the note decay- it's all you hear until sound ends.
I could easily record the audio and send it your way if that would help. I have a scope and meter, but know just enough to be dangerous with both. Again, I'm a player, not a tech. But don't mind fixing myself if possible.
Thanks
Adam
On Sep 25, 2008, at 6:41 PM, Scott Nordlund wrote: