Emerson microwave blows fuses
I do some appliance repair, but never really tried to fix a microwave. Someone gave me an Emerson MW8118SL that is about 1 1/2 years old and I figured I'd give it a shot. The main fuse was blown. I replaced it, started to heat a cup of water and it blew again in 1-2 seconds. I found your site and checked the monitor switch. It came apart for me, but when I reassembled it, it tested good. I changed the fuse again in case that was the problem, but it blew it again in 1-2 seconds. Also, I can not find a parts breakdown of it on appliancepartspros.com. Any suggestions would be helpful.
You might find it hard to find exact parts for Emerson parts anywhere but as far as common parts like door switches, diodes or fuses are typically the same on most microwaves. Since you repair appliances I will warn you to take parts availability in account when you take in a microwave like this. What you don’t want to do is take the time to diagnose just to find you can’t get parts because then you may have a hard time collecting anything for the job (especially if they dropped it off at your shop they won’t come back to get it).
If the monitor switch came apart I would strongly recommend replacing it. If you do appliance repair you may have a micro switch that will work just make sure it is rated for at least 15 amps and has the NC terminal (it is ok if it has both NC and NO terminals). If it still blows with the new switch make sure the door latch is hitting all the switches when you closed the door.
If it still blows the fuse you need to narrow the problem down to if the problem is on the low voltage side or the high voltage side so unplug the wires off the relay on the smart board that supplies voltage to the high voltage transformer. If it still blows fuses you know it is in the low voltage side and if it doesn’t you know it is on the high voltage side. Then from their start unplugging devices until you figure out what it is. Make sure when you unplug things you make sure the wires don’t touch anything (it will render the test useless if the wires short out). Make sure you have a few fuses it may take a few to figure this out.