Modern Electronics (was Re: List charter mods & headcount... ;

From: Dwight K. Elvey <dwight.elvey_at_amd.com>
Date: Tue Jun 22 19:38:22 2004

>From: "der Mouse" <mouse_at_rodents.montreal.qc.ca>
>
>> 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.

---snip---

Hi
 Interesting. I know how, just about every part of, a microwave
oven works and I wouldn't have done this. I'd have thrown
the thing away and bought another at a garage sale.
 You also have to realize that I'm the kind of fellow that
once did a field repair on broken points spring of
a car with some cardboard, tape and several springs from
some ballpoint pens. It got me home.
 Also, I doubt that a normal wall light switch is rated for
that large of an inductive load.
Dwight
Received on Tue Jun 22 2004 - 19:38:22 BST