No Power at all after loud short buzzing sound

The cook relay on your control board is shorted, and the unit is cooking whenever you close the door.

When the magnetron overheats, its thermostat opens, shutting power down until the unit cools to a safe level, then power is restored.

I regularly repair these with my $54.95 service, which includes insured return shipping.

Details are here, or for full information and instructions, please e-mail me here at [email protected] and remind me of your full model number and symptoms.

Check this link for some tips that you can try http://www.partselect.com/microwave+no-heat+repair.htm

Hope that helps..........

Whirlpool Microwave Buzzing Loudly - ApplianceBlog

www.applianceblog.com/.../26531-Whirlpool-Microwave-Buzzing-Loud...

Aug 12, 2011 - 10 posts - ‎2 authors
My Whirlpool MT4155SPS-2 microwave oven has recently started to buzz loudlywhen operated. The sound is getting louder and more frequent ...

Whirlpool making intermittent loud buzzing noise Microwave ...

www.fixya.com > ... > Microwave Ovens

Whirlpool microwave ovens making intermittent loud buzzing noise related questions and answers. Ask your ... ...loud buzzing noise and it doesn't heat. i just tried it again and let it run for 1 minute. ... Question about Accuwave Microwave Oven.

Troubleshooting the Microwave: Potential Problems ...

www.appliancejournal.com/.../troubleshooting-the-microwave-potential-...

If your microwave buzzes loudly and produces no heat you probably have a defective power .... I have a whirlpool oven range and it's less than a year old. .... Humming sound stops when I open door to remove food, but when door is closed, ...

Whirlpool Microwave Ovens - Consumer Affairs

This is a strong indicator the magnetron is fried, also! this is the most expensive part to replace in the microwave oven, and in most cases cheaper to replace the whole unit.

It sounds like the magnetron may have either failed or is not being supplied with the extremely high voltage required to run it.

YOUR SAFETY IS PARAMOUNT

This is a job for a professional but if you are safety clued up, here's instruction.
Make sure the !!!!capacitor is discharged!!!!! before attempting any sort of repair.
Check the door interlock switches first then the high voltage diode with either an AVO model 8 or moving coil meter on high resistance range for short circuit, (DVM's won't show the fault!), the capacitor can fail and go short circuit, the feed fuse on the primary of the high voltage transformer and then finally, the magnetron is best checked by substitution.
Hope that helps.

Load test.

A simple safety test.
Place 1/2 litre of water in a glass container. Measure the temperature of the water.
Place in microwave and heat on full power for 1minute.
Measure the temperature after it has stood for 1minute.
If the temperature difference is more than 9 degrees Celcuis the magnetron is working and producing about 700Watts of heat.
If your microwave is labelled with 900 or 1000Watts. That is about right.
If the temperature is less then the magnetron is not working properly and may need replacing.

This a only a rough guide and any doubts you should consult an authorised service agent.

It sounds like the magnetron may have either failed or is not being supplied with the extremely high voltage required to run it.

YOUR SAFETY IS PARAMOUNT

This is a job for a professional but if you are safety clued up, here's instruction.
Make sure the !!!!capacitor is discharged!!!!! before attempting any sort of repair.
Check the door interlock switches first then the high voltage diode with either an AVO model 8 or moving coil meter on high resistance range for short circuit, (DVM's won't show the fault!), the capacitor can fail and go short circuit, the feed fuse on the primary of the high voltage transformer and then finally, the magnetron is best checked by substitution.
Hope that helps.

Load test.

A simple safety test.
Place 1/2 litre of water in a glass container. Measure the temperature of the water.
Place in microwave and heat on full power for 1minute.
Measure the temperature after it has stood for 1minute.
If the temperature difference is more than 9 degrees Celcuis the magnetron is working and producing about 700Watts of heat.
If your microwave is labelled with 900 or 1000Watts. That is about right.
If the temperature is less then the magnetron is not working properly and may need replacing.

This a only a rough guide and any doubts you should consult an authorised service agent.

It sounds like the magnetron may have either failed or is not being supplied with the extremely high voltage required to run it.

YOUR SAFETY IS PARAMOUNT

This is a job for a professional but if you are safety clued up, here's instruction.
Make sure the !!!!capacitor is discharged!!!!! before attempting any sort of repair.
Check the door interlock switches first then the high voltage diode with either an AVO model 8 or moving coil meter on high resistance range for short circuit, (DVM's won't show the fault!), the capacitor can fail and go short circuit, the feed fuse on the primary of the high voltage transformer and then finally, the magnetron is best checked by substitution.
Hope that helps.

Load test.

A simple safety test.
Place 1/2 litre of water in a glass container. Measure the temperature of the water.
Place in microwave and heat on full power for 1minute.
Measure the temperature after it has stood for 1minute.
If the temperature difference is more than 9 degrees Celcuis the magnetron is working and producing about 700Watts of heat.
If your microwave is labelled with 900 or 1000Watts. That is about right.
If the temperature is less then the magnetron is not working properly and may need replacing.

This a only a rough guide and any doubts you should consult an authorised service agent.

Hi,
When the microwave won't heat, but you hear a loud buzz, you usually have a defective power diode, high-voltage capacitor, or magnetron. Also 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.
Please let me know if the provided information has been helpful.
Please rate me if the information provided was able to help you.

Q - The microwave display counts down and the inside light is on,  but nothing is heating and the fan is not running.
A - This most commonly is a bad door switch, other possible problems are a faulty relay or solder joint on the power module, but a bad door switch is most common.
 Q - My microwave is running and sounds like it is working but will not heat up anything.
A - Many thing can do this but, common things are....loose high voltage wire.....poor solder joint on board.....magnetron.....power relay.....
Q - The microwave makes a loud "hum or buzz" noise but will not heat up the food?
A - 9 times out of 10 this is usually this is a bad magnetron, the other time is sometimes a bad high voltage diode. See components section.

Have you tried putting a cup of water in it and cooking on a low power level? If it buzzes only when it is on the cook cycle, that would narrow it down. More detals might help us help you, including the model number.