Microwave

[fixit guy]

I have read how to test magnetrons but can someone tell me step by step instructions for the procedure?  (where to place testing leads) Do you ohmn the antenna to F or FA?  Also how is the best way to determine that the mgnetron is bad?  I have tested good magnetrons against bad and I get the same readings so an enlightment here will be educational.

Thanks.....

[Trying to help]

You should have approximately 1 ohm across the mag terminals and open from each to ground.  Unfortunately almost all mags ohm fine (you're actually surprised when you find one) but fail under load.  Fortunately when testing the cap and diode, a good test is just that, good.  When they ohm good, they are good, not like the mag.  Usually you eliminate all other components and are left with only the mag when diagnosing.

[fixit guy]

That's the problem I am having they all test good.  Will a megohmmeter test these ?  My multi meter won't even test a diobe.

[appl.tech.29501]

You need a meter that will read RX10K for capacitors and diodes...some of the digital meters are a little harder to use when testing these type of components, I normally use analog meter for microwaves

[Trying to help]

You will need the full voltage of the 9 volt battery in a good old fashion cheap analog meter ($15-20) to test the diode.  Digital meters will not work.  Some have diode settings but they are not for the type of diode in question.  I carry a cheap Universal (Brand, not the type) analog meter for just this reason.  The problem is the Mags are failing under load.  If you check a Diode and Cap and they test good, they are good. Transformers are the same way, it they ohm good, they are usually good.  On Transformers, across the primary input windings and the filament windings you should have an ohm or so and from the hi voltage output wire (the one by itself that goes to the cap and is the only thing on that side of the cap) you should read approximately 60-120 ohms from it to ground depending on make and model.

[fixit guy]

Thanks a lot guys, I purchased a new meter today(analog) and with this information maybe I can test these components. I understand that a 9 volts battery is required to test the diobe.  In the past I have disconected the magnetron, run the microwave a few seconds and carefully held the wire to the mag terminal to see a spark. If I found a spark I knew the mag was bad. This unit I am working on now has no spark so testing is in order.

 

Thanks...