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.