Microwave Trips Breaker and Blows Fuse Hi, just had a incident with our Built in microwave tonight. The unit was not in use and it blew the circuit breaker. Upon resetting the breaker the unit would not come back on. I removed it from the build in and took the cover to find outr the fuse was blown 125 volt 20 amp ceramic. I did not have the correct voltage fuse so just to try it I substituted a 20 amp 36 volt fuse it all I had. The unit powered up and worked fine setting on the counter. I will get the correct fuse tommorow. But my dilemma is to reinstall it with the new fuse with no rhyme or reason as to what caused the problem. I thought I would let it reamain on tonight to see if it blows again before I reinstall it. I looked around and smelt around did not see anyting burned or melted. Like I said we were not using it at the time the breaker tripped.There is a small portable TV on the same circuit that has been there all along it went out thats how we new the breaker tripped. We bought them both new( TV and Jenn-Air Microwave) at the sane time 5 years ago. Any thing come to mind for me to check before I reinstall. One more time and I will mount the fuse in a different(sattelite) location.(easy to get to!) Regards Bob Northington 816-525-2271
Since the internal fuse blew, the problem has to be either a surge from the power source, or an intermittent or transient short at some point beyond the fuse. With the unit unplugged, I would first look at the varistor (surge absorber) on the control circuit board to see if it might have taken a transient. It may look charred, distorted, etc. Then I would look at the door interlock switches and mounts to see if the switches are clicking properly and if they are aligned and secure. The purpose of the monitor switch is to blow the fuse (and usually the breaker) if there is aan interlokc problem. Next would be a look at the condition of the wiring from the fuse holder all the way back to the power cord. Then just for good measure, I would test the power outlet. A toaster is a good high-current load to use. But I don't think the problem's in the wiring or breaker. If you or a friend decide to work on it, we have *critical* safety and disassembly info at our site, which is linked at our listing here on FixYa: http://tinyurl.com/yzjozk You can find the wiring diagram, helpful exploded view diagrams and order parts by entering your base model number (without the suffix) here: http://tinyurl.com/gv383 Be sure to use a proper ceramic appliance fuse that's meant for the job.
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