[eyefish]

Gene,

I have determined that the HV Diode is no good. It tests 'infinity' (open) in both bias directions (tested with a high quality Fluke Meter)
I would like to know; in your opinion; if I should order more parts than just the diode? I didn't get any spark whatsoever out of the HV Capacitor when I went to discharge it prior to removal of the diode for testing. I did not, however, test the capacitor, after I found the diode bad.

Thanks,
Al

<snip>
My Amana ACO 1860 AW (over the range) microwave is not heating.
It seems everything else works fine.
I located the tip sheet inside under control cover.
Fuse tests OK.
Magnetron tests OK.
HV Transformer tests OK except for Filaments to chassis tests shorted....sheet says they should test infinite.
Does this tell me that the HV transformer is NG? <snip>

[eyefish]

Gene,

Please....I need your help. (Amana ACO 1860 AW 6 yrs old)
I fault traced everything, & everything specked out OK.
All values of all the pertinent parts were within spec. (as per service manual, & tech sheet behind control panel.

I replaced the diode, because I got a false negative on the original one, but the new one tests the same as the old one. (I rechecked them both with a 10V battery later, & instead of testing with an OHM meter...I checked current flow one way & the other....current flowed one way, but not the other)

So now my question is: some unknown part needs replacement...should I just replace the magnetron; even though it tests fine using the test procedures of the service manual & spec sheet?
It's an expensive part to buy if that isn't the problem for certain.

Please advise ASAP.
Thanks,

Al

[Gene]

Hi Al,

Remove the wires from the high voltage transformer primary winding and check for 120VAC between them while the control calls for heat and the door is closed.

If there is 120VAC then the magnetron is bad.

If there is no proper voltage then the problem is a bad secondary switch or a bad control board.

Gene.
P.S. Did you remove the transformer wires from the magnetron and the capacitor before testing the filament winding?

[eyefish]

Hi Gene,

I already ordered a magnetron 2 days ago, & it's on it's way. Should be here today or tomorrow.
I has seen a small *note* in the service manual that read: "If everything tests good in the HV system; including the magnetron.....and there is still not heat...replace the magnetron..."
And in answer to your *PS*question....I had NOT removed the HV (red & white) transformer wires, or the capacitor wires before testing the filament winding.....I realized that later.
I removed them later, & tested the filament windings & the capacitor again, & then they tested OK.
I have been able to do all my diagnostic testing & diode replacement so far through the front of the unit, after removing the control panel.
I don't think I will be able to replace the Magnetron through the front.....I believe that the unit will need to be removed from the wall, & the casing opened up.
Do you know of a way to replace the magnetron through the front without removing the unit from the wall?

Thanks Gene..
You are a gentleman for helping people diagnose & repair their appliances by sharing your many years of accumulated knowledge.
I do the same thing on a Volvo Repair forum because I am a retired Volvo Dealership Master Tech, & have been helping people as you do for a number of years.

I will let you know how I make out with the magnetron after I install it.
Are there any tricks with positioning it or with a gasket?

Thanks again,

Al

[Gene]

Originally Posted by eyefish

...I don't think I will be able to replace the Magnetron through the front.....I believe that the unit will need to be removed from the wall, & the casing opened up...l

Hi Al,

Thank you for your good words.

You are absolutely right - there are no other ways to access the magnetron. You are on the right track. Good luck.

Gene.

[eyefish]

Gene,

Microwave fixed.

I received the NEW magnetron this morning which I got on ***** for less than 1/2 what they asking in appliance parts stores (local & online)
Installed it, & that was it!
The hardest part of the repair was removing the unit from the wall & re-installing it later (it's an over-the-range-unit) & removing the outer case.
Thanks for your assistance.
I wouldn't have known where to begin fault-tracing without your guidance.
You are extremely helpful in answering questions & giving links to repair manuals & part numbers, etc!
And you are extremely knowledgeable!
Thanks again for your help!

Al

[Gene]

You are welcome. I'm glad you were able to fix it.

Gene.