I have a 5-year old over-the-range Maytag microwave connected to 20-Amp service on it's own circuit. A few months ago, it began tripping the circuit when I would open or close the door. It never trips the circuit when it's cooking; just when I open or close the door. Also, it doesn't happen every time... initially, it would occur only about once a month... now every 3rd or 4th time I use it. (I've recently quit using it... )

I would appreciate any assistance, especially since I know it will cost close to $100.00 just to get someone to come look at it. Is it "fixable", or should I just replace it?

Just guessing here, but since the door switch controls the interior light, so there may be a short in the switch or the wiring from the switch to the light socket, and possibly causes the short to be disturbed by vibration when the door is opened.

Is it possible the door hinge is pinching a wire inside?

Since the minimum service charge is $100, and the unit is 5 yrs old, perhaps the money may be spent better towards a new unit.

You can always take the covers off the microwave and inspect for some burned wires. If we are dead shorting a 20 AMP circuit, Id say that would be enough to leave a mark where the problem is. Look for burned up door swiches, wires, connections etc.

A WORD OF CAUTION:

Discharge the capacitor before tampering with any wiring on the capacitor, magnetron, or transformer. The transformer ranks thousands of volts. Turn the ciruit breaker off before attempting repairs, and as I said, discharge the capacitor by shorting the two terminals on the capacitor out. If service to the magnetron is needed I recommend having it services by a qualified professional because once you tamper with the magnetron or tamer with the door your're supposed to do a microwave leak check on the unit, you have to have special equipment to do this.

But all in all, you should be able to at least pinpoint the problem, since you say it doesn't do it while its cooking, then that probobly elemintates the cooking circuit anyway.

Replace it, average life of a microwave it about 5 yrs, I am not sold on Maytag brands, read the consumer reports, Whirlpool or Kenmore made by Whirlpool seem to offer more reliabilty, less repair issues, used to sell all brands, its just my experience.