My microwave oven popped last week - it stopped working and there was a characteristic smell of burned out electronic components. I was toying with the idea of trying to fix it, but after a quick look inside I decided that I wouldn't bother. I can live without the joy of that kind of thing these days...!
I've had about 15 years use out of the oven so I don't feel too bad about recycling it now and treating myself to a new one.
One thing I did notice when I looked inside though... there was a sensor of some sort on the end of a long cable. It was just dangling there doing nothing. I found a little mounting point into which it should have been inserted. My diagnosis is that many years of temperature cycling eventually caused the sensor to pop out, which meant that it was no longer doing its job properly. I reckon that led to overheating and failure. There had been a couple of unexpected shutdowns in the past few months, which I had attributed to dust blocking ventilation slots. Maybe they were precursors of this terminal failure.
PS Any suggestions for a replacement microwave oven? The main requirement is to be able to do good baked potatoes. My old combi-microwave could get them to about 95% of the quality of a slow conventional oven bake in sub-20 minutes. Probably 900-1,000 W microwave, with about a 1,000 W grill. Turntable big enough for a large dinner plate. Ideally, an inverter type microwave. Preferably no more than £150. My last one was much too complicated for my needs. Simpler is better.
The guts of microwaves are pretty scary.