My microwave oven packed up last Friday. The turntable, fan, light and timer were all working, and leaving it unplugged for awhile had no effect, so it was something more serious than just a thermal cutout tripping. Connecting via a wattmeter showed only 300 watts or so of power being drawn, so the magnetron was not firing.
On opening it up, I discovered a fuse in the HT circuit which had blown. Fortunately, I managed to find a supplier of the required part online; then I found a local supplier in a proper actual real live shop. Having visited said real shop and obtained the part today, I fitted it. Now, fuses don’t usually blow for no reason; the magnetron could have been faulty, which would have seen off the fuse. But the only way to find out was to replace the fuse …..
Anyway, so far it seems to be working fine. There’s actually surprisingly little that can go wrong with a microwave oven. I’ll be posting an article about them here shortly.