Re: akz145 oven
I had the same problem after a power cut. So I ordered and fitted a new button, which made no difference.
The left hand knob, which needs to be in the off position, is attached to a potentiometer on the board, so I turned it quickly left and right continuesly for a couple of minets, and Hey Presto it worked.
So I think a dirty or greasy pot stopes it from working.