Kitchenaid Microwave not working

This is a combo microwave/oven unit. The control panel works fine (was replaced in 2009). The microwave does not start up. I can select a time to cook and then press start and the microwave beeps 3 times (which I think is normal) but it does not turn or cook.

There are no error codes shown on the control unit.

Any clues?
Thanks

Hi.

Turn off the unit, open the control panel, disconnect the flex ribbon from the control board and clean the edge of it with isopropyl alcohol. Reconnect and check if that’s works. If not - then it’s most likely time for the new microwave, because the controls are no longer available.

Simon.