We are full-timers and our microwave is starting to go. There is a relay or something that keeps the unit on after it is supposed to shut down. After giving it a couple of quick slams on the side it...
A neighbor gave me a high dollar Sears microwave that worked sometimes if you slammed the door. I replaced a $1.50 microswitch on the door latch and used it for many years. Many switches on ebay.