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Picture of Getting Useful Bits from a Microwave Oven #1
This Instructable is about recovering the useful bits that can be found in a defective microwave oven.

VERY SERIOUS WARNINGS:
1. Not only is this a mains-powered device, it can contain extremely dangerous high voltages. The capacitor that drives the magnetron has a built-in bleeder resistor for safety but do not rely on it!
2. As the first stages of this growing i'ble involves disassembling the magnetron, you must also be careful that you are not exposed to a toxic chemical----beryllium oxide which, if inhaled, can cause  incurable damage to the lungs
3. Because these cheap "consumer" devices are assembled with self-tapping screws, also be aware of getting metal splinters in your fingers.
The appropriate steps will be highlighted as they are encountered.

The magnetron had failed in this unit, otherwise everything else was working. This is characterized by the gradual decay in efficiency (e.g., ever longer cooking times) over a period of time. Having the magnetron properly replaced usually costs more than purchasing a replacement oven. So this is the first item to be removed.
 
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Step 1: Open the Case

Picture of Open the Case
Before starting, ensure that the mains lead is unplugged!

As this is a reasonably nice stainless steel case that is destined to replace my very under-sized mail box, I have been careful in handling it to reduce scratching.

Note that most of the case screws are at the back, but sometimes they can be on the side, and even underneath. See the red circles. As this case is to be re-used, keep these screws. The extra holes in the side toward the front of the case are for a wall-mount bracket and, for now, can be ignored.

My microwave oven was out of order, it
kept blowing up the power fuse; finally the trouble was traced to the power
capacitor that was shorted.

So, the power capacity was changed and
the oven worked again, but now the magnetron becomes noisy with a jackhammer
noise when it is working.

This noise starts when the magnetron
starts working, but it stops after some two minutes while it continues to work
up to the time adjusted for it to finish its operation.

What has happened to the magnetron?

Is it possible to fix it?

On the other hand, it is my best
suspicion that it is the magnetron that is making the noise and not the
transformer.

What is your experience in this situation?

This is exactly the sound (click on the link below) I am
getting from my microwave oven, but it does not go and on until the machine
turns off; the sound stops some two minutes into the operation, and the
remaining time there is no longer the sound or noise – for the remaining time
it keeps ‘quiet’ up to the completion of the time period it has been adjusted
to operate, or I turn the switch knob to off.

https://www.youtube.com/watch?v=CF0RXKF4puQ

Thanks for any help or information.