A:Answer This is a known issue that Electolux/Frigidaire will not address, at least in my case. They said" Your Warranty is expired Too bad" basically. As I have shared with others, there are a few good YouTube Videos out there that talk about this, and in some cases people have replaced one or more of the three micro switches that are on the inside door. One is called a monitoring switch. All most all of the known issues started around 12 to 15 months of the units life. Mine died at 14months. If you go to Menards.com. Lowes.com, or if you go to google type in 'Breaker switch blowing with firgidaire microwave(Put the model in the search)' You will fins a ton of horrible stories and issues on this.
In regards to if the fuse is blown on the inside, under the control panel, check it with a continuity tester or visually if it is clear glass. If it is blown replace with a 20 amp fuse I am guessing(Mine was ) which you can buy those at most hardware places.
