Home » Questions » Information [ Ask a new question ]

Fuse blowing when door is opened

Fuse blowing when door is opened

Fuse blows if door is opened before end of heating. Can be opened anytime not in heating part of cycle.


"The door safety interlock switch is bad or the connection terminals at the magnetron capacitor is loose causing arching/intermittent voltage surge. WARNING the capacitor is storing high voltage and is a potential shock hazard.

A qualified repair technician is highly suggested to service your microwave oven."


I had the same problem with a 3 year old GE Microwave. It comes down to a design flaw. I changed the capacitor and all three switches and still had the problem. The issue turned out to be the white plastic housing that holds the 3 switches. Over time the hooks from the door latches wear away where they meet the white housing. In my case the top hole wore down faster than the lower hole causing the switches to release at different times when the door is opened which will in turn send a power surge to blow the fuse. Attached a picture of the worn piece.

Certainly check the continuity of the switches first. Second I would replace the plastic piece holding the switches. I say do those first because they are the most likely causes and you don’t have to take the microwave down to do it. Lastly, if you still have problems, I would change the capacitor (DANGER - capacitors hold a potentially deadly charge)."

I took away the switch in the middle. That switch simply short 120 AC power when door opens. If there still power, it just blow the fuse. It is overkill, because another switch (top one) opens when door is open and cancel 120AC power from outlet. It is double protection (not necessary for my opinion). Timing is the problem and with flimsy plastic supports of all three switches shortening switch can close before power interrupted by top (power) switch. That will blow the fuse. And one can change a dozen of switches and other parts, but will have the same problem. Can try to redesign switch support, adjust switches position making timing reliable, but just eliminating shortening switch is an easy and fast solution. I blew up four fuses in couple weeks, but now microwave works without problems.

I found the schematic and trouble shooting chart folded inside the back of the control panel on my JVM3160DF2WW. Did you find a solution to your fuse blowing problem? Mine is blowing the 20A fuse at first when opened door during cooking. I found the lower left hand bracket for the door hinge was loose (the spot weld broke). I fixed it with a small low profile bolt and a nut with lock washer in a pre-drilled hole behind the door when you remove the door. The door was sagging a bit before the fix but it blew another fuse on startup. I need to check the door switches.

Most homes have circuitry that's limited to a 3000w per set and you can have multiple sets such as when set runs the ceiling lights other sets run other rooms walls or sections of the house. However just 3,000 watt limit makes it so you can't run a frigerator the toaster and a heater or a microwave on the same circuit. If that was your case there would be some understanding of why you could be tripping the circuit when you open the door in microwave but I don't think that's your case. You should test the microwave on an unoccupied circuit (that is one that has little or nothing plugged into it most likely a garage). If the device were to trip the circuit all by itself that would mean that there is a short within the microwave and the door could be all or part of the trigger. A spot where our concurred should be noticeable you are in fact creating a surge which is what trips the breaker and this should be noticeable if you were to get inside it. Since you have a limited electrical knowledge I would recommend replacing the unit strictly on the grounds that is much safer than having a microwave burn down in your kitchen.

Asked by: Guest | Views: 274
Total answers/comments: 0