My microwave failed three weeks ago, it appeared to function perfectly apart from the fact that there was no heat generated. I put a spare microwave in its place, and the second microwave (completely different model from a different manufacturer) failed in exactly the same way today. So I have two dead microwaves in the space of three weeks. Both were plugged into the same wall socket.

From reading here, it is probably the magnetron which has failed in both cases. So my question not what happened or how to fix the machines, but WHY it is happening: what possible common cause is there? The in-wall wiring is old and we've had problems with failing fuses before in our kitchen.

Can a power surge via the wall socket make a magneton fail? Or what else could it be?

Thanks for any suggestions!