OK, I don't have model information handy, but this is so textbook I thought I'd start a thread and see where it goes.
I've got a trusty 14 year old Sunbeam-branded (but Sunbeam has told me they never carried parts for it) microwave that I bought at Target. Yesterday it worked fine. Today the fan, lamp, and carousel have all stopped. Clock still works. Timer still works. Settings still work. It still heats food. But the fan, lamp, and turntable no longer work. Last time I used it, all were fine. Today none work.
On more tidbit: I confess that I let the interior get pretty dirty. And there's a few places where the finish is worn through to bare metal--but never any sparks or anything.
So I'm thinking a fuse or connection that controlled these three systems has failed, but cursory searches yesterday said something about something called a "smart board." Any thoughts?
So far I haven't tried opening anything up on it to look for component access--there's a big "DANGER: ELECTRIC SHOCK! YOU COULD DIE!" sign on the back, but I don't know if microwaves have capacitors or if this is just for the kind of people that stick forks into plugged-in toasters so I didn't get too involved.