I have a bit ovva problem with the amp in question. Basically, every time I try to swap between the basic 4 (A,B,C,D) presets, after pressing the specific button the channel swap doesn't occur. I dont know if it is some kind of a contact problem, but I dont think so, seeing as same thing happens wether I am using floorboard or not.

Example: Channel A was active. I pressed button D 4 times, no reaction. Then I pressed B and ta-dah! It swapped. And it is all random!

Any advice on the matter?

Yours, Jussi
Try moving the amp's rotary knob to a different position, then check the floorboard. Do this for each of the amp's rotary knob settings. It may give us an idea of where to start.