Luckily the potentiometers and tactile switches are all easy to replace, if you have decent soldering skills. I'd do that over sending it in to Germany and paying a boat-load. These are the potentiometers
, and here is a small set of tactile switches.
I think if it were the typical capacitor problem, you'd be experiencing symptoms more related to that specific issue, namely the "turns on but only LFO lights come on" bit.
If you haven't re-installed the OS, that would be the first thing I'd do. But if buttons/knobs are sticky, that's obviously a hardware issue.