Fuse keep blowing up

I have serviced 100's of microwaves and the most common problems for microwaves not working 1)fuse blow(but display will be dark), 2)not plugged in(or house fuse blown) (microwave display is dark and other outlets would be off) 3) connections to one of the door switches is burnt out. The display is not dark but microwave will not work. The wire going to the switch looks black right at the switch.(this wire must be removed and a new connector attached to wire and then reattached to the switch

If it happens when you push start it probably in the high voltage system. Depends on if your microwave has an nverter or a transformer, capacitor, and rectifier. If any of those parts are bad it wil lblow the fuse.as soon as you push start.

Sorry to read about your problem, I hope this helps you out.

you have a defective control board

I tried to help you. Please help me and Rate/Vote on my response, thanks and good luck

If it blows as soon as you hit the "Start"pad to cook, it has a shorted high voltage capacitor.

You have a shorted high voltage capacitor.

Here is a link you or someone you know can use to test it, but please read the safety info:
http://www.gallawa.com/microtech/cap_test.html

For more help from Emerson visit here or get help using your appliance at 1-800-898-9020. Get help locating a servicer or parts at 1-800-695-0098.

Emerson parts are distributed by Fox International and their number is 800-321-6993. Or you might try e-mailing [email protected]

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

If it blows the fuse as soon as you hit the START button, it's almost certainly a shorted high-voltage capacitor.

If it blows a few seconds after you hit the START button, it's probably the high-voltage transformer. You'll possibly also smell a faint electrical burning smell from the rear vent after you shut if off.

If it blows the fuse as soon as it's plugged in, you probably have a shorted door switch, a shorted varistor, or an internally exposed wire shorting to the chassis, etc.

check high voltage transformer and high voltage diodes, condencer, and magnetron.,

In case it's still helpful, I'll inject a little sanity into the replies.

If the fuse blows as soon as you hit Start, it's probably a shorted high-voltage capacitor. That's usually economical to repair.

If the fuse blows a few seconds after you hit Start, it's probably a shorting high-voltage transformer. That's usually not economical to repair.

It's not radiation (non-ionizing RF by the way) that's the hazard, it's the voltages.

The fuse is generally located on the bottom of the chassis of the microwave. You have to remove the outer cover on a counter top model - or the front panel assembly on an over-the-range model. There are several reasons why it may blow. If the fuse is loose in the holder, the fuse and the holder should both be replaced. If - with the microwave disconnected from the wall - you can easily turn the fuse with your fingers while it's in the holder, then it's too loose. What happens is the loose connection generates too much heat, causing it to melt internally. If so, you'll usually see a ball of solder at a point where the cap meets the body of the fuse. If the fuse blows as soon as you plug the oven in the wall, or when you open the door, the problem is likely with the door switches. You can find my files "doorsw.txt" and "safety'txt" via Google. They give you the safety warnings and cover the diagnosis and replacement of the door switches. If the fuse blows as soon as you hit START, then it's likely that you have a shorted high-voltage capacitor. If the fuse blows a few seconds after you hit START, then it's likely that you have an overheating / shorting high-voltage transformer. If you still have a problem, please wirte back with more detail. Be safe!

WARNING: Microwave ovens are the most dangerous consumer appliance to service due to up to 5,000 V at high current inside. Even with the power off, there is a HV capacitor that can produce a lethal kick. This capacitor must be discharged before touching anything in the microwave generator circuitry. DON'T remove the cover yourself unless you fully undertand the SAFETY issues involved in working inside a microwave oven. A microwave oven is possibly THE MOST DANGEROUS common consumer product to service. About the only "easy" fix would be a blown fuse, if it keeps blowing, don't go any further unless you know what you are doing. Your likely options are a blown high voltage cap, diode, or the magnetron. Good luck(but luck has nothing to do with it ;] )