our GE Advantium just started making an intermittent ‘zapping’ noise, accompanied by a flash of light. it is working, but it seems a little weird. I’m wondering what might be causing this and how serious of a problem it might be. thanks.
I would not use a unit that was doing this.
Are you sure that something metal is not in the oven cavity.
Check the cover (usually looks like a piece of cardboard) for the magnetron cavity. Sometimes they can get some crud on them and then the magnetron arcs to this and then to the frame.