A year ago, my wife heated food on a plate that had metal stripes in it. We saw sparks fly but we quickly stopped the cooking process.
Since that day, the microwave oven would make a loud buzzing noise only while cooking some types of food, especially popcorn.:)
Yesterday, it made it's last buzzing noise and now it does not heat at all.
What could it be? The mag tube? (this is my guess)

Any help is appreciated!

Thanks
Marcelo

Right now, all noises sound normal to me, no burning smell either. Just doesn't heat anything.
Model # is JVM1850BF001. It's a GE SpaceMaker XL1800.
I called GE and they said they have a 10 yr warranty on the magnetron, but they'd charge me the visit + parts + labor if any other part is defective... I think I want to test them before having them visit or get the kit someone else mentioned GE sent to that person.
PS: I'm aware that it is dangerous and I've read the steps to discharge the capacitor and other precautions.

Thanks for the reply Gene!

Here's the conclusion to the story:
I called GE to see if they could send me the mag tube. They said they can't send it to ordinary people like me, only a tech can replace it. Then, they charge $80 for the visit.
They declined to let me know what the repair would cost (labor only), so I had to schedule an appointment. Good thing is, the service guy called me before coming and told me it would cost me $180 total to replace the mag tube.
Then I said "thanks, but no thanks" and bought a samsung microwave for 230 including shipping and tax. (same cu ft, same wattage, similar features).
I'll have to do the install myself, but 180 to replace a part under warranty sounded a little bit too much.
Thanks all for the replies!