To fix the buzzing microwave, I replaced the magnetron with a new one. But it continued to buzz. I then unscrewed the magnetron from the body, and put it on the table. I turned it on, and quickly left the room. There was no buzzing sound heard.

What is the solution to stop the buzzing? I'm convinced the magnetron was tightly screwed to the unit, and the buzzing wasn't because it was loose.
Any ideas anyone?