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On Tuesday, August 21, 2012 12:32:57 PM UTC+8, Winston wrote:
gregz wrote:

wrote:

I have a faulty Sanyo microwave oven EM-S1057, whereby the tray
rotates

and the bulb lights up but there is no heat produced. With the help
of

repairfaq site I managed to trace the faulty to a shorted magnetron.
The

magnetron is of the Galanz type part number M24FB-210A and it is
available online.



However I am a little reluctant to replace the magnetron since I am

afraid other components might be faulty and the repair cost would not
be feasible.



Is it safe to check the voltages of the high voltage transformer
with

the magnetron unplugged?



Thanks in advance.



Vernon



I think the transformer needs a load.



And at ca. 4.1 KV one would need a HV divider probe.



It would be trivially easy to kill yourself doing this.



(Just an observation.)



--Winston

Is there a way of checking the transformer?

Basically - power it up with no load, if it doesn't blow the fuse, there's a
high probability its OK.

Don't attempt to draw sparks from the HV terminal - I heard about an
apprentice doing that, the screwdriver he used had a crack in the handle,
and when his boss returned from the van with parts - he was laying on the
floor dead.

A S/C magnetron could have caused the rectifier to also fail S/C, a lesser
possibility is failure of the doubler capacitor. Sometimes there's a surge
supressor - looks similar to the rectifier, but has 2 diode symbols k to k
one big one smal - that can also fail S/C.

In over 2 decades I've never bought a microwave, very often its worth
rescuing units put out for scrap - if by any chance the don't work, they're
still a handy source of spares.