Taking apart an OLD microwave ove

I had a old microwave over which I picked up at Monkey Wards (now out of business) back in 1977/78. It just kept on running and running and running. The "touch" keypad was difficult to operate and it was clear that it wasn't quite as powerful as it was but it was there.

Last week, it stopped. We had already planned on replacing it with an over the over model (more about that in another post) so I wasn't upset.

I decided to take it apart "just to see."

Some comments on what I found:

1) That thing was SOLID! It was really, really well put together.

2) It had two (2), two pole (plus pilot) contactors. One was for the "browning" element. The other was for fail safe purposes. The final switching to the transformer was by some kind of triac (there was a diagram showing all the power and contactor wiring -- the "logic" just showed the

120 volt and "safety" and sensor interfaces).

3) When I had opened things up, I almost wished I had been a little more careful (because of dirt, I ended up bending the outer sheet metal to get it off). Turns out the Triac (or whatever) had broken off from it's heat sink. Without the heatsink, it failed (the proof was that the wiring to the triac showed some heat damage to the insulation. I was almost tempted to get another triac and put the thing back together.

I "salvaged" a bunch of stuff like:

1) The control panel -- it's powered from 120 volts. I might be able to find some use for it. My older girl said she might enjoy having it so I might find some way of getting it powered and not be a shock hazard to her.

2) The contactors (both nameplated for 15 amps.

3) The MAIN transformer, high voltage diode, and voltage doubling capacitor.

4) The magnitron tube (still has the heat sink but I want to see how they focused the magnetic.

5) The permanent magnets (two flat "donuts". The magnetic circuit was completed by some heavy gauge sheet steel. I might keep them and play with the effects on conductors dropped between the poles.

6) Some power hardware including a combo fuse block and male "slip on" terminal block.

7) The MANY microswitches (safety, door switch, temperature probe sensor)

8) The overheat sensor on the microwave cooling fins (NC).

9) The thermal fuse that detected whether the contents of the over were on fire!

10) The 50 rpm "stirrer motor"

11) The cooling fan.

For now, I will just move the stuff to a "junk box."

If anyone has any projects to suggest, let me know.

Anyway, I figured some of your would be amused by the whole thing.

Reply to
John Gilmer
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Take it to the dump or just dump it on the side of the road somewhere.

Kirk Johnson - "Stretchin it to the max since 1977."

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Reply to
Kirk Johnson

The transformer is a nice hunk of iron for when you want to wind your own transformer. Many microwave transformers have one side intentionally shorted to ground, so be aware of that if you intend to use it unmodified.


Reply to

I too have a "junk box" full of similar parts. Never know when you might have a use for them. If you are into Ham radio it seems that there is always something coming up that needs a part your just threw away.

A friend had a microwave that was arcing. He bought a new one and was throwing out the old one. Out of curiousity I took it home to see what it might be. When I opened it up I found a fried moth in the waveguide. Cleaned it out, put the oven back together and it worked like new.

Reply to


Be careful with that transformer. Several amps at 2-3kV is potentially lethal.

Ben Miller

Reply to
Ben Miller


The cap (used in the voltage doubler) is reated for 1400 VAC!

Reply to
John Gilmer

Schhhhht schhtttttt...so much statik

can any read me ////??? is this radio picking up my speech... dangit !

copy dat....

[Title] / an enclose the magnetrons magnetic output throu a torroid n to yor New stereo and when it acts up increase the Vol and draw it with the Bass & Treble control atached to the torroyd,and Welcome 2 the Idiot Squad

Dahhh wat r we takin it apart again 4

Roy's Injun cuzin Joseph from the plains jackt his internetface box.idid. just to tell ya how we donit. okay

C:-o Joe

Out !

Reply to
Roy Q.T.

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