Whirpool Microwave My microwave just stop working,No power at all.I've opened it and found a blown fuse.I replaced the fuse w/ the same rating but when i power on the fuse blown again.I can't find any defective parts inside.Pls. help,I'm also a technician.Thank you very much.

You probably have a blown fuse inside your microwave.

Unplug your microwave and turn it around and remove the screws holding cover on and then remove the cover. Look for where the power cord goes into the back of the unit and follow the black wire from the cord to where it ends. It should stop an either a circuit board or a fuse holder. Make sure that you replace the fuse with the same amperage fuse as what you take out. You will find the amp rating stamped on one of the silver collars on each end of the fuse. Good luck!

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

Could be the fuse inside the microwave is blown. You will need to unplug the microwave and remove the front control panel. Inisde the microwave housing you will need to trace the electrical wire coming into the unit. Usually you will find the in-line fuse located on the black power wire. You can pull the connectors off the fuse and test it with a continuity tester. If the fuse is blown replace it but make sure you use the same amp rated fuse as you removed. If the fuse blows again then there is an electrical short somewhere in the microwave.

Took microwave out, opened back, 15amp fuse blown. Replaced all ok.

Yes. The white inside the glass that you are describing is a blown fuse. To find out what size fuse it is look around the base or top of the fuse. You will see engraved something like "125V 5A. You can pick these up at Home Depot or Lowes in the electrical isle. You can also type www.google.com and enter the word "fuse" and then the size it is. (125V 5A) If you have found this information at all helpfull, please rate my solution. Thanks D. Lange

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

Just cleaning is not enought.The terminal is loose and that isusually the problem most of the time.Replace them with new ones and I think you be happy.

If the diode failed by opening, there may be no other damage. If the dioded failed by shorting, the alternating current may have damaged other components. Ohm it out. You can get diodes from digikey.com, mouser.com, or radio shack or any electronics or appliance supply. If the diode is charred and you can't get the part number, the oven rating can be used to select a replacement. Since the fuse was 10 amps, the diode should also handle at least 10 amps. If you can power the unit and read the voltage at the diode input this will give you the power (volts times amps). It's always worth trying as it's cheaper than replacing the unit.