Microwave oven - magnetron failure

[DTJ]

My microwave decided to arc up and fail yesterday.

It's old and the mica screen has seen better days. I assume that grease and food vapours built up to the point arcing occurred on the nose of the magnetron.

It melted the nose and also melted through the side of the microwave cabinet into the cooking cavity.

Nothing overly technical but I thought it was interesting.

[Brumby]

Oooohh.  Good fun.   

[DTJ]

Oooohh.  Good fun.   

It made a nice loud hum when arcing and the inside wall of the cooking cavity was glowing red near the magnetrons location.

[Gyro]

That's an impressively burned antenna! Yes, grease build-up on the waveguide window and also running empty / with dry contents can cause that. All is not lost though. They are replaceable, a simple pull-off, push on. You can find them on ebay (search 'magnetron cap'), pick one with the same shape hole (triangle) in the top - I don't know if this is strictly necessary but there must be a reason why they come with different hole shapes.

It sounds as if the magnetron itself still has plenty of output power available!

[DTJ]

All is not lost though. They are replaceable, a simple pull-off, push on. You can find them on ebay

Ooops. I pulled the old one apart and tossed it all except for the neat little synchronous platen drive motor.

It's burned a hole through the cabinet wall anyway!

[strawberry]

it happen because of some dirt or mica failure

[DTJ]

it happen because of some dirt or mica failure

The mica window between the magnetron and the food cavity?  It was pretty bad condition, I'd replaced it about a year ago.

[EPAIII]

That's neat. Did you get any video?

[DTJ]

That's neat. Did you get any video?

I was too busy trying to reach over and unplug it so I could take it outside. It started smoking quite a bit.