In the inside of the microwave there is thi...

Posted by MicrowaveSvc on Jul 04, 2009

That's the waveguide cover. Quite often this arcing is due to grease or food particles stuck somewhere in the cavity of the oven or stuck on or behind the waveguide cover. The waveguide cover (also called a spatter shield) is usually about the size of a playing card and often held in place by a plastic rivet. It can be fragile, and the metal edges of the oven behind it can be sharp, so be careful! The cover and the metal behind it should be cleaned with a mild, non-ammonia cleaner. The area will first have to be sanded smooth and cleaned and dried thoroughly. Then you can apply some high-temperature appliance paint, available from places like Wal-Mart, Lowe's or Builder's Square. If your waveguide cover is burned, it will need to be replaced. It provides important protection for the magnetron. Please reply back with your brand and model number so we can point you to a part supplier.