Glowing Magnetron.

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Panasonic Inverter microwave oven model NN-S751WF.

Fault - Oven starts to cook but soon shuts off.

Customer told me one of his children turned the oven on for several
minutes with nothing in it.
The magnetron was a bit bent out of shape.

After testing the oven with a secondhand Magnetron,
and finding everything to  work o.k., I bought a new 2M261-M32 from

The oven does work with the new Magnetron, but there is a red glow in
the top
near the terminals that concerns me. There is no glow from the
secondhand unit.

Could the new unit be faulty?

Thanks in advance,
Russell Griffiths.

Re: Glowing Magnetron.

Hi Russell ,
I will let you know of my experiences with microwave repairing.
Firstly I will assume you know all the safety stuff about the HV

I have safely been able to measure the filament/heater winding - which is
around 3v (extreme caution needed as it is above 2kv)
Luckily I haven't had to do this very often due to the risk.
I have gone by a very simple and maybe crude way of listening to the magie
at switch on and the overall temp after running it for a set time.
"Most" magies will give a noticeable increase in loading within the first 2
seconds (as the filament/heater warms up)
and after 1 min heating a cup of water the magie will be less than 50 deg
(warm but not hot)
Due to the replacement cost of most mw's I haven't seen many lately - so I
cannot confirm the heater as visible, all the ones that I have seen to date
are enclosed and not visible at all.
But due to the HV and current if there was an issue with the terminals and
insulation etc - it WILL become very noticeable very quickly.

my 2 cents worth anyway
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Re: Glowing Magnetron.

"Jeff" <see_inside_message> wrote in message
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Russel and Jeff,

my two cents worth. :) when I was repairing them in the late 1980s,  I
hearing after pushing the start button. 1.  a low level hum.  then, 2 a
sizzling sound.then, 3 a much loader hum as the magentron starts
to emit microwaves.

On the subject of caution,  the supply in the oven is lethal.  A friend in
the 80s showed me, through an experiment,  just how lethal they are.


Re: Glowing Magnetron.

I concur Mitch,
My test setup is completely hands and body free (nowhere within 3 feet).

I don't measure the HV much anymore as I do most by ear - and you don't need
to most times


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