Moog Opus 3: middle C will not attack until release completely runs out

[burymyteeth]

Interesting issue on a Moog Opus 3. Everything seems to be functioning great except for the Middle C! If I have a longer release, that note it will not attack again and generate a new note if the release is still ringing out. When it rings out I hit the key and its back. It is the only note with this behavior. Any idea on where to start?

Thank you!

http://www.synthfool.com/docs/Moog/M...Sfi2cjhNQlqzVQ

[The Dude]

I'd check the key contacts for that key. I believe those are metal contacts and not the rubber contact strips. It could be bent, sticking or otherwise. There could even be something lodged in the contacts. I've found all sorts of things in keyboard contact assemblies- paper clips, coins, etc. All manners of things can fall between the keys. I've also seen drinks spilled into the keyboard making things sticky. Since it's just one key, it almost has to be something in the key contact itself. I can think of no setting that would effect only one key.

[Enzo]

Oh paper clips were a pain. They'd bounce and slide around so the problem moved

I'd tend to agree, it sounds like a contact issue. This unit is WAAAY too old to have keyboard splits and note assigns. In a modern synth you can program the keys for various functions, and one could be inadvertently programmed for what you are seeing.

Although each contact has a little e-cap and diode going on. Small e-caps of that age are always suspects.

U12 is the key assigner for the C notes, you might scope your bad note pin compared to its fellow notes.

[burymyteeth]

Thanks very much. I will open it up and inspect the contacts again. But, I can adjust the release so there isn't any, and it basically fixes the problem so I'm pretty sure its not the contact, pretty weird! Thank you for the suggestions on where to start with components specific to that key Enzo, I will give it a go!

[Enzo]

Don't dismiss the contacts yet. You can set the release so it doesn't happen, but it is possible you are just masking the issue that way. SO worth a little attention there


Does this one have polyphony? Or is it one note at a time?

[burymyteeth]

Thank you, will take a look this evening, Opus 3 is polyphonic yes.