Prophet 600 Note Triggering Issue

[mattjhuber]

Hello all!

I have GliGli modded Prophet 600, and have had a random issue come up.

Every 6th (sometimes 5th and 6th) note that I play will randomly trigger an incorrect note on ONE oscillator. It is an intermittent issue and does not go away after tuning (tuning completes without error).

Any ideas?

Here is a video that shows the issue:



Thanks so so much!

[synthchaser]

You have an oscillator that's out of tune. You hear it every 6th keypress because it's a 6 voice synth and it round robin assigns key presses to a voice.

[mattjhuber]

You have an oscillator that's out of tune. You hear it every 6th keypress because it's a 6 voice synth and it round robin assigns key presses to a voice.

Thanks for the reply -- is there a reason why it would be an intermittent issue?

[synthchaser]

I think I may have showed this in one of my Prophet 5 repair videos, but a good reason is if the oscillator isn't stable, and it comes in and out of tune. Find the oscillator in question and attach a scope to the CEM3340 chip and you'll get to the bottom of it very quickly.