I'm a little bit baffled. I'm not an electronics guy, but everything else on the sammichSID works fine except the rotary encoder.
I've noticed that occasionally that the patches scroll through of their own accord. When I switch it on and off, the encoder works in one direction only. Sometimes, just not at all. Mostly I would describe its behaviour as 'erratic'.
When I select patches from software / MIDI controller there's no problem.
I've checked for shorts and I've touched up all points that look like they're not 100%, but otherwise perhaps someone can point out something I can't see.