22 Jun
2004
22 Jun
'04
8:41 a.m.
I've only ever possessed one [microwave oven], it
currently still
seems to cook as well (or badly) as it ever did so I've had no cause
to examine it in any detail.
Same here.
If it breaks, it will get looked at (although I
suspect, without ever
having checked, that a new megnetron will cost a significant fraction
of the price of a microwave oven). Still, there's always the chance
that the controller or its keypad will give up the ghost.
That's what happened with my oven. It was bought at a garage sale some
years back, and worked fine for some time (years). Then after a
lightning storm, it started beeping intermittently at odd times when it
shouldn't. After a few days, it occurred to me that if it could beep
when it wasn't suppsoed to, it could turn on the microwaves when it
isn't supposed to. I opened it up and found that the keypad and
control board all culminated in two relays, one to control the fan and
the other the microwave-generator. I checked, and a new board would
cost almost as much as we paid for the oven. So I yanked the whole
thing, wired the fan and magnetron together (I almost always used it on
high anyway, and lower power settings worked by imposing a <100% duty
cycle on the magnetron), and controlled it with an ordinary wall light
switch, on the principle that it's too simple for much to go wrong.
But this still didn't mean I dug into the underlying principles of the
magnetron. For my purposes, it was a black box: mains power goes in
here, microwaves come out there.
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