Blown Fuse this unit keep blowing the FUSE after it's been replace any Idear what is causung this fuse to blown Emerson MW8775W Microwave Oven

a blown fuse is a dead short of the circuit
it could be a failed power board , control board , megatron, light wire anything powered by the fuse
good advice is to take it in for a proper diagnosis and quote

First check is the main fuse of the unit. On countertop units, you will need to take the shell off. The fuse will be close to where the cord comes through into the unit. OTR units, this main fuse is usually behind the control panel or possibly behind the vent. Usually the fuse is obvious if blown, otherwise test with an OHM meter, if open, replace fuse.
Some brands will also have a thermal cut-off fuse in the incoming voltage line to the control board. Older Maytags and Samsungs have this fuse in it. This thermostat looking fuse is usually above the oven cavity somewhere under the outside shell. Sometimes you can get to it through the vent of OTR models. Test with an OHM meter, replace if open. Use the VOM
God bless you

HELLO.

the problem your are experiencing with your microwave oven is a failed interlock switch.
Be careful when closing your microwave door. Slamming the door too hard is one of the main reasons that the interlock switch is damaged.

Slamming the microwave door shut can easily blow the microwave fuse, but they can also blow due to problems with the interlock switches.
A microwave oven will not function until the fuse is replaced.

Instruction on how to replace fuse on microwave.

1. Unplug the microwave from the electrical outlet to prevent electrocution. Place the microwave in a well-lit area to be able to locate the fuse.

2. Use a screwdriver to remove the outer cabinet of the microwave, and follow the power cord to the fuse. The fuse is located 2 to 3 inches within the microwave and is attached to the power board.

3. Observe the fuse to determine if it is blown. Blown glass fuses will produce burn marks on nearby surfaces, or the internal fuse wire will be black and melted, while ceramic fuses show no outward appearance of being blown.

4. Determine if a ceramic fuse is blown by testing it with an ohmmeter. If the ohmmeter reads zero ohms, your fuse is not blown. Other readings on the ohmmeter show that your fuse is blown.

5. Replace the blown fuse by popping it out of its holder, and snapping a new fuse in its place. Tighten the fuse clips by squeezing them together with your fingers.

6. Replace the outer cabinet of the microwave, and plug the microwave back into the electrical outlet. Test the microwave to see if it's working properly.

thanks.

Maybe... Did you check the high voltage diode?... A shorted diode keeps the fuse blown... Ty

Hi

When your microwave oven doesn't work at all, it means interior fuse inside the microwave has blown (usually a part inside the microwave makes this fuse blow). Sometimes a bad fuse holder inside the microwave cannot hold the fuse tight enough and the fuse will blow as well. If the fuse isn't the problem, check the door hooks and the door-release button. When these are broken, the door switch doesn't activate, so the oven can't work. It can also be due to a stuck or faulty door switch which might have blown the interior microwave fuse.

Please do rate the solution and revert for further assistance.


Thanks
Rylee

Usually, when your microwave oven doesn't work it all, the internal fuse (thermal fuse) is blown. This fuse protects both you and the oven. When it blows, you need to have a qualified appliance repair technician replace it.

The reason for this is that if you do not have any experience and training with microwaves, you can get a SEVERE shock, even if the oven is unplugged. THAT being said, if you still want to know where the fuse is get back to me. good luck.

ALSO, as you may know, a small microwave these days is under fifty bucks at walmart.

Hi 

If your microwave oven doesn't seem to work at all, check these:

Fuses Usually, when your microwave oven doesn't work it all, the internal fuse (thermal fuse) is blown. This fuse protects both you and the oven. When it blows, you need to have a qualified appliance repair technician replace it.

Door switch If the fuse isn't the problem, check the door hooks and the door-release button. When these are broken, the door switch doesn't activate, so the oven can't work.


Please do rate the solution as "FixYa" if found useful and revert for further assistance.

Thanks
Rylee

Most of the manufactory has put them in the back where the power cord comes in.

I have replaced the main fuse on this model. Though blown main fuses are common in this model, it will not even turn on when they blow, so your problem is most likely NOT a blown fuse. I had heard of your problem so, when replacing the main fuse inside one, I looked for additional fuses and saw none. The store was wrong. Even if it were a fuse, the security Torx screws mean that you couldn't replace the fuse anyway.

This microwave seems to have been haphazarly been recommended by Consumer Reports, but it is terribly unreliable. The turntables break when popping popcorn, the main fuse repeatedly blows, and they also stop heating.

That makes it sound like a bad high voltage transformer.

Do you detect any burning smell?

Do the windings of the high voltage transformer seem blued or blackened?

They should be copper colored or maybe a little darker due to the varnish.