I don’t think this has anything to do with the ModyPoly as the voice assign timing is identical to the original CPU. ut just to be sure I recommend updating the ModyPoly to the latest firmware. See https://tubbutec.de/tubbutec-firmware-updater/
Cool, I gave it a shot – it didn’t fix the issue but thank you anyway. Good to have the latest firmware.
I’ll have to think about finding a repair guy somewhere close by (easier said than done though). The synth works perfectly after being warmed up, but it’s still quite annoying knowing that something inside is a bit off.
After a very long time of being powered off (=several days to a week) it can take nearly 2 hours to get in tune after a cold start, while in normal conditions (=powered off through the night or for less than 24 hours) it gets in perfect tune within 10-15 minutes. Strange.
If anyone is reading this with experience of a similar issue with just a single voice, any insight would be much appreciated.