On Oct 16, 10:07*am, mynick wrote:
On Oct 16, 4:01 am, Erik wrote:





In article
communications,

*jeff_wisnia wrote:
mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

Jeff

Or as a guy I know would so eloquently warn... "Dont ya'll be messin
with that s**t lest you know what you doin; it'll up'n give yo ass a
dirt nap"

Good advise too. I hate 'dirt naps' anymore, especially now that I'm a
bit older.

Microwaves reached disposable appliance status eons ago... if it's not
in warranty, spring for a new one, they're cheap.

Erik

I meant what is going to happen if you try replace original magnetron
with one that has 4.13v or 3.6v filament voltage but original hv
transformer gives 3.15V- Hide quoted text -

- Show quoted text -

Those numbers don't seem to make any sense at all. Sounds like maybe
something is shorted or the capacitor or rectifier is shot.

BE VERY, VERY CAREFUL. LETHAL VOLTAGES!!!!!!!.

My advice is always, don't mess with it unless you are a competent
high voltage/radio transmitter technician!
There are voltages of 5000+ volts and potential RF radiation that can
fry your eyes (cos that's what it does in minutes to meat, eh?). In
effect a m.wave oven is a one kilowatt radio transmitter in a tin box!
And much less than that can easily kill you!!!!!!!!

The circuit is complex enough that the typical do it yourself-er may
not be able to follow. For example we recently fixed, in less than 20
minutes, a microwave that the owner, a capable sort of chap for most
'carpentry type' repairs, but not an electronics technician, thought
had a bad component in the power supply (HV transformer, rectifier,
capacitor etc.) .

Then he thought it was something to do with the control panel!

Initially I had thought it might be the contacts of the relay on the
control panel that switches most of the power the m.wave uses. One
could hear it closing but no power!

It wasn't any of those! The problem was a defective door micro-switch
(Canadian Spec. not necessarily same as USA by the way!) that
prevented basic 115 volts AC from reaching the fan, the power supply,
the interior light etc. etc. A somewhat basic fault as it turned out.
We had a spare micro-switch of the same spec. from a junked m.wave
fairly easy install, stand back, since the cover was still off, for a
test and it was all done.

Not only the wrong diagnosis, twice, plus my first thought about the
control realy; but the owner had put the cover back on incorrectly and
it had a slight gap where microwaves 'might' be able to leak right
near the door 'handle'! Not good.

For goodness sake 'BE CAREFUL' a replacement m.wave can be had for
around $50 and the risk is not worth it.