The electrician could find no problems with the wiring but the microwave is definitely fried. A SHARP™ repairman came today and confirmed the diagnosis.
The dishwasher is also dead and gone. I washed all the dishes in it by hand. It was not the most pleasant experience.
It can’t be a coincidence, something must have happened to knock out both appliances. My guess is a power surge. Or else it was a murder-suicide in the kitchen (love) triangle.