Magnetron replacement

The only thing I promise about this blog is that it will include some of the random happenings in my life. Sure, I'm working towards my 25 goals, but I have plenty of other stuff going on as well.

Last week, about 11pm, I decided I wanted a microwave beef and bean burrito. The microwave looked and sounded like it was warming my burrito but the burrito never heated. Doh!

I was annoyed that my microwave broke because it wasn't that old. Some research found that the magnetron probably died and that most people buy a new microwave instead of paying to get a magnetron replaced. Since I need to save some money for this upcoming cruise (goal #20) I would whine a lot before forking out the $300-$400 for a replacement stainless steel over-range microwave.

Since I'm a bit of a cheap skate I decided to learn to fix my own microwave. Attached is what I did to fix it.

Disclaimer: I am not trained or certified in microwave repair. You probably shouldn't be taking advice from a random blogger. If you mess things up there is a chance you could die. Don't do that.


Step 1: Remove microwave from wall and transport to working location. Since it is way heavy and awkward my living room floor became my work location.

Step 2: Remove lid. On mine this was one piece that wrapped all the way around. It was held on by a dozen or so screws. Righty-tighty lefty-loosey. Don't touch stuff yet. Figure out what magnetron it has and buy a replacement. I found one on Ebay for $35.

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Break to explain what I think I know about microwaves:
You put food in the microwave and it gets hot.

The food gets hot because the water, fat, etc resonates (vibrates) when it gets hit by RF energy created by the microwave magnetron. The magnetron is like a radio transmitter that creates RF energy at around 2450MHz.

So, the challenge of the microwave is to create 2450MHz RF energy from 60Hz 120 Volt wall power. To do this the 120 V AC is turned into higher voltage AC, then to even higher voltage DC, and finally to RF.

Did I mention there is high voltage involved here? Yeah, there is. In fact, there is a capacitor that stores energy for this process even when the microwave isn't plugged in. You don't want to discharge this energy into yourself. At best it will hurt like a mofo. Worst case you will die.
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Step 3: Discharge the capacitor into something that isn't you. My microwave had bleeder resistor (small cylinder with wire that goes from capacitor to the metal frame). This resistor will slowly discharge the capacitor when the microwave is unplugged. However, even with this, it is smart to discharge the cap. Again, death by fixing microwave would be a lame way to go. To discharge the capacitor take an insulated screwdriver and short the metal part across the capacitor. It might spark or pop.

Step 4: Replace magnetron. Unplug and unscrew.

Step 5: Put new magnetron in, replace wires, put cover back on microwave. Don't screw up putting screws back in. You don't want 2450MHz energy leaking out of the microwave and into your body.

Step 6: Mount microwave and test. Did I mention this thing is heavy?

I was super happy to find that this fix-it job was easier than I thought. It went well and worked. So, for $35 and some time I saved $300. Saving money will help several of my goals.

My microwave, topless:

Magnetron: