I have a microwave oven - standard cheap LG unit. It's no longer working (it made electrical sparking sounds), so I opened it up to see if it's possible with a DIY repair.

First thing I did was of course to discharge the capacitor for safety reasons.

I cannot see anything obvious here, but I am not experienced in microwave repair at all.

I'm including a video (the most interesting) and a photo.

I have tested the magnetron using the continuity check on a multimeter. It seems to be working. I've checked the big diode and the thermal fuse. Is there anything else I can check?

YouTube Link: Showing how some electric sparking happens near the magnetron

Shows the innards of the microwave

Extra link: A couple more photos if relevant

  • 4
    Microwave magnetrons are dangerous things. I'd expect it is very unlikely that you can economically repair a cheap microwave oven that has no obvious simple fix and where there appears to be a sustained high-voltage (~5000V) high current arc ocurring. A replacement might cost $70 - I wouldn't risk my life for $70. Jun 29, 2017 at 12:29
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    Yes, fixing it may even cost more than a new cheap microwave oven. If I end up throwing it away, is there perhaps some interesting parts I should salvage for fun projects?
    – T.K.
    Jun 29, 2017 at 12:34
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    Yeah, I would not suggest repairing a microwave as a DIY project. The risks are too high and new microwaves are cheap.
    – Machavity
    Jun 29, 2017 at 12:47
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    Ditto. Nothing this inexpensive is worth risking your life (or someone else's) over. I admire your precautions such as discharging the cap. But this sounds like a good time to just pull out the transformer and build a Jacob's Ladder with coat hanger elements to impress the kids. Hint: If you do, put it inside a transparent PVC pipe so nobody can touch it. You can take the magnetron apart to salvage the magnets, but do not ever do anything with the radiating element - the insulation around it is nasty material, and one breath of the dust from cutting it can be much worse than asbestos.
    – SDsolar
    Jun 29, 2017 at 14:00
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    Yes, for instance the transformers are great high voltage sources. In third world countries they use them to step up electricity for lomg distance transmission. Jun 29, 2017 at 16:49

1 Answer 1


Conclusion - it's probably wise not to try to fix this. As suggested by comments, it's just going to be too dangerous and not economically feasible. I will scavenge the parts from the old microwave and buy a new one to replace it.

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