I hope that it would be possible to somehow repair the printed touchpad of the microwave oven, but there's a possibility that it might prove unfeasible. 

In that case, I might replace the membrane keypad with pushbuttons. Here I have a source of them: the front panel printed circuit of a fax machine that's on its way to e-heaven. 

I only need 15, and here's 35, so ample margin for a learning curve and any accidents.