The part(s) or condition(s) listed below for the symptom Microwave is sparking or arcing are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The waveguide cover might be damaged and arcing or burning. If this is the case or if the cover will not stay in place, replace it with a new one.
If the microwave is sparking or arcing in the cabinet area, and not in the oven cavity, you will likely see smoke or there will be a burning smell. One of the appliance's door switches could have shorted and is causing the sparking or arcing. You should inspect each door switch for burn marks or damage and test the components with a multimeter to determine if any the door switches are malfunctioning.
If the microwave is sparking or arcing behind the waveguide cover in the oven cavity, you will likely see smoke or there will be a burning smell. The appliance's magnetron is one of the components that could be damaged and causing the sparking or arcing. Inspect the magnetron for burn marks or damage and replace if necessary.
If the microwave is sparking or arcing in the cabinet area, and not in the oven cavity, you will likely see smoke or there will be a burning smell. The appliance's diode is one of the components that could be damaged and causing the sparking or arcing. When the diode fails, it is often visibly burned out. Inspect the diode and if the diode is burned out, replace it. If inspecting the diode proves inconclusive, test it with a multimeter that uses a 9-volt battery or put a 9-volt battery in series with the diode. When the leads are reversed, the diode should only have continuity in one direction..
The paint on the interior of the microwave might be chipped. If the paint is chipped, the interior metal will be exposed, causing the microwave to spark or arc. Check the interior of the microwave for any spots where the paint has chipped away. If there are any damaged spots, gently sand the compromised area and touch them up with microwave oven interior paint.
The paint on the interior of the microwave might be chipped. If the paint is chipped, the interior metal will be exposed, causing the microwave to spark or arc. Check the interior of the microwave for any spots where the paint has chipped away. If there are any damaged spots, gently sand the compromised area and touch them up with microwave oven interior paint.
Some microwave ovens will have cooking rack supports on the interior walls. Inspect the rack supports for any burnt spots or damage. If there are any burnt or damaged spots, replace with new supports as needed.
If the microwave is sparking or arcing in the cabinet area, and not in the oven cavity, you will likely see smoke or there will be a burning smell. The appliance's control board is one of the components that could be damaged and causing the sparking or arcing, although this is rarely the case. Inspect the control board for burn marks or damage and replace if necessary, although you should confirm that other more likely defective components are functioning properly first.
If the microwave is sparking or arcing in the cabinet area, and not in the oven cavity, you will likely see smoke or there will be a burning smell. The appliance's main control board is one of the components that could be damaged and causing the sparking or arcing, although this is rarely the case. Inspect the control board for burn marks or damage and replace if necessary, although you should confirm that other more likely defective components are functioning properly first.
If the microwave is sparking or arcing in the cabinet area, and not in the oven cavity, you will likely see smoke or there will be a burning smell. One of the appliance's micro switches could have shorted and is causing the sparking or arcing. You should inspect the micro switch for burn marks or damage and test the component with a multimeter to determine if the switch is malfunctioning.