Korg Mono/Poly

Sorry to hear this. I had a similar problem with my M/P (non functioning of an envelope generator) which turned out to be circuit board trace corrosion from a leaky cap. I can't help but suspect you might suffer from a similar cause. Got a multimeter and the schematics? Get in there!

I posted my experiences here:

http://www.gearslutz.com/board/electronic-music-instruments-electronic-music-production/608707-korg-mono-poly-envelope-problem-easy-fix.html

Best luck in bringing your M/P to full health. 

Paul

Sent from my iPhone