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bimbbobway

How to determine if the magnetron or transformer is bad.

9 posts in this topic

I am looking for a surefire method to determine whether the magnetron or the transformer are bad. Many times the transformer windings test good but in the end the transformer is bad. Same with the magnetron.

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There's more in the circuit than the magnetron and transformer.

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Yes I know that. But the cap and diode are easy to test.

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Mag less than 1 ohm between terminals and open from each terminal to ground.

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I use a 100 - t0 - 1 voltage probe with my VOM to test for 3000 to 4000 voltage  DC at the probe to see if the Magnetron will work, if there's no power

then i'm looking at the Diode or Transformer circuit.

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Never had a transformer test good and be bad that I can remember.  The readings you should get are 0.3 - 0.5 ohm on the primary winding, less than 0.1 ohm on the filament winding, and  65 - 120 ohms on the secondary winding.  Primary and Filament to ground should be infinite.  The magnetron tests just as Spannerwrench described.   If everything in the high voltage side checks good then replace the magnetron.  The magnetron is a vacuum tube, and if it looses it's vacuum then it won't work. No way for a tech to test the vacuum so it's a process of elimination.  Every transformer I've replaced had either open windings or was arching from a breakdown in the varnish on the windings.  The latter displays a nice fireworks show while energized.  

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I am looking for a surefire method to determine whether the magnetron or the transformer are bad. Many times the transformer windings test good but in the end the transformer is bad. Same with the magnetron.

 

 

Try the Willie Method ™:  http://appliantology.org/blog/1/entry-236-the-willie-method-%E2%84%A2-for-testing-a-microwave-oven-magnetron-tube/

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That's the method I have used for years. Thanks for confirming that. I've had several transformers lately that have tested good on all windings then ended up being bad. Its a bummer when you order magnetron put it and it turns out to be a transformer.

Could there be a way to test the output of the transformer? Could we build a dummy load to put on the transformer to test it with?

That's the method I have used for years. Thanks for confirming that. I've had several transformers lately that have tested good on all windings then ended up being bad. Its a bummer when you order magnetron put it and it turns out to be a transformer.

Could there be a way to test the output of the transformer? Could we build a dummy load to put on the transformer to test it with?

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That's not bad ill share it with my techs. Thanks. I'm still gonna keep searching for a more solid answer. If I find one ill let you know.

That's not bad ill share it with my techs. Thanks. I'm still gonna keep searching for a more solid answer. If I find one ill let you know.

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