Microwave stopped working

here are some items to check for troubled microwave
Bad Magnetron Symptoms What are some bad magnetron symptoms to watch out for?
The following is a brief list of some of the most common signs that your magnetron is about to give out:
Heating: Either the microwave is not heating up at all, or the heating performance has degraded noticeably.
Burning Smell: A burning smell (non-food related), may be an indication that elements of your magnetron are overheating. In this case, switch off your microwave immediately, and arrange for a repair or replacement.
Unusual Noises: All microwaves make a bit of a hum, but if it's become much louder - or sounds like unusual vibrations - your magnetron may need to be replaced. Watch out for a clicking sound as well - that's a tell-tale sign of a magnetron that's about to fail.

Is It Worth Replacing The Magnetron In A Microwave?

It really depends on the cost and age of your microwave. If it's somewhere between five and seven years old, you're in the right period of time for a replacement anyway.
There's little point spending good money on repairing or replacing a magnetron if the rest of the appliance is likely to give up the ghost soon anyway!

Symptoms of a Bad Microwave Diode? (Answered!)
A microwave diode is one of the most important components in the appliance. Without it, it's impossible to generate the heat required to heat foods and drinks placed in the oven cavity. Unfortunately, the component can go bad, so it's important to understand the symptoms of a bad microwave diode.
Generally, the symptoms of a bad microwave diode include sparking, buzzing and humming, and the appliance failing to heat. Running a continuity test helps to determine whether the diode has a problem. Getting a new diode for replacement is the solution if the current one fail the continuity test.


3 Symptoms of a Bad Microwave Diode The following table shows the summary of the symptoms of a bad microwave diode as well as what you can do to fix the problem:
Symptoms Solutions 1. Microwave buzzing and humming Inspect the diode, test it for electrical continuity, and replace it if it fails the continuity test. 2. Microwave not heating Start by inspecting the capacitor and magnetron because they may also be responsible for making the microwave fail to heat. 3. Microwave is sparking Locate the diode, inspect it, and test it for continuity. Replace it if there's no continuity. There aren't too many symptoms of a bad microwave diode. The most common ones include sparks & burning smells, the microwave not heating, and the microwave making humming & buzzing.

1. Microwave Starts to Have Heating Failures

Apart from a failed main control board, a faulty fuse cavity, a blown line or thermal fuse, and a faulty door switch, the high-voltage diode could also be the possible reason why the Whirlpool, Kenmore, GE, or KitchenAid microwave is not heating.
Your microwave failing to heat is a perfect sign of a faulty diode, which means you should get a new one for replacement.

2. The Microwave Starts to Pop Sparks

Sparks in your Kenmore, LG, Samsung, or Whirlpool microwave could be a sign that the high-voltage diode is defective.
Also, a burning smell from your microwave can indicate that the diode is bad. A burned-out diode can break into two, wear out, or short.
Immediately locate the diode in the cabinet next to the magnetron and replace it.

3. Microwave Starts to Make Noise

Your microwave could be buzzing and humming because the high-voltage diode is defective.
Apart from the diode, other components that can make your microwave make noise are the plate & drive motor, cooling fan, and magnetron.
Keep in mind that you can't repair a bad diode. You can only replace it with a new one.

Safety Warning

While repairing a microwave, the chances of falling into electrocution by the high-voltage capacitor even after unplugging the power cord from the socket are very high.
So you need to be very careful when doing the diode test.
To begin with, the high-voltage diode is located close to the high-voltage capacitor. In fact, one of its ends is attached to the high-voltage capacitor.
And as you know, a microwave capacitor carries high power voltages, which can be quite lethal. It is therefore important to start by discharging the capacitor before getting to the high-voltage diode.
Although the capacitor can store charge for a long time, touching both its negative and positive terminals with a metal screwdriver blade will drain all the charge in seconds.

Testing the Microwave Diode

Before you even attempt to replace the diode on your GE, Whirlpool, or KitchenAid microwave, do a functionality test to confirm your suspicion.
You can visibly confirm the diode is burned-out when you see physical damages.
In case there are physical damages, use a multimeter to test if the diode still has a continuous electrical path.
To test the diode for continuity:
Touch the positive and negative terminals of the high-voltage diode with the multimeter probes.
If the diode test negative for continuity on both of its sides, the diode has failed and will need a new one for replacement.

Microwave maiking loud noises

Tip #3: Weird Noises

. A high-pitched noise while the microwave is in use means there's a good chance the magnetron tube or diode is failing. If the exhaust fan or magnetron tube are the culprits, you will need to call a local appliance repair service.
DIODE HIGH VOLTAGE You might have an issue with the high-voltage diode if your microwave is generating an odd or loud whirring sound. This element, together with the magnetron and the capacitor, is a part of the high-voltage circuit. The cabinet needs to be taken out in order to get to the diode.


BUZZING AND HUMMING Most buzzing or humming noises are frequently caused by the fan motor, vent fan, magnetron, or any combination of these. This noise from routine operations gradually gets louder over time.
As the microwave oven warms up, the oscillation happens, and the fan helps keep the mechanical parts from overheating. You might need repairs if the volume of your microwave suddenly increases.
Try running the magnetron at a lower power setting while putting food inside to see whether the magnetron is the cause of your problem. This will cause the magnetron to switch on and off to maintain the proper temperature. If the magnetron is the issue, there should be less noise.
CLICKING NOISES Even though your microwave might not have a revolving plate, some models spin food using a glass turntable or plate. This component aids in ensuring even heating throughout your meal. However, occasionally clicking noises may result from this action.
If you constantly hear clicking, see if your glass plate, roller ring, or track needs to be cleaned. These are simple to clean with soap and water, but you might have neglected to do so. The location of the plate is what determines the other option, so be sure it is still on course.
POPPING As you prepare food or after spilling food, you might describe the sound of your microwave as popping, crackling, or snapping. However, these tones frequently come from dishes with significant water or fat content, particularly sauces.
POWERFUL SOUNDS When it comes to microwaves or other appliances, these noises continue to be the most alarming. You should replace your microwave if the device starts to make an electric-sounding noise called arcing.

If you notice that while using your microwave, the electricity flashes in addition to making a sound.

Stop using your microwave if this occurs and you notice a hole in the back o WHY DOES MY MICROWAVE MAKE A VIBRATING NOISE

There can be various reasons behind a microwave making vibrating noises. Some are given below.
POWER MOTOR Your microwave's drive motor may be malfunctioning if the turntable is making an odd noise. The majority of microwaves with glass trays turn the tray with a motor-driven coupler or a roller guide.
Access must be made through the bottom of the oven because the motor is normally found below the floor. Normally, a holding screw holds the motor in place, and two wires are connected to it as well. The motor must be replaced if it is creating a grinding sound.
its because it is now dangerous.
A loud humming or buzzing sound could result from a damaged magnetron
PUSH COUPLER If your microwave is making an odd noise, the drive coupler for the turning tray can be the cause. The majority of microwaves with spherical glass trays revolve around the tray on a roller guide using a motor-driven coupler.
A drive coupler with an offset center roller is sometimes used in models that employ a rectangular tray to move the tray guide from side to side. Remove the tray and roller guide from the oven for either style and then check the coupler. Before you can pull the coupler off the motor on some models, you might first need to remove the motor from the bottom.
ROLLER GUIDE If the turning tray in your microwave makes an odd noise while rotating, there might be an issue with the roller guide underneath the tray. A motor-driven coupler is sometimes used in microwave ovens with spherical glass trays to turn the roller guide.

It may be a shorted high voltage diode or a failing magnetron.

Here are some links you or someone you know can use for test help, but read their safety warnings first:

http://www.microtechfactoryservice.com/microtech/diode.html
(if it's not shorted or burned, it's probably okay)

http://www.microtechfactoryservice.com/microtech/mag_test.html

You can find links to helpful exploded view diagrams and order parts here.

I'd recommend that your bookmark this link to your favorites.

SAFTY FIRST

UN -PLUG IT,,,,, THAT "FUNNY SMELL" SOUNDS LIKE IT IS SHORTING OUT
PERHAPS THE MEGATRON HAS GONE BAD, THE MEGATRON IS THE
HEART OF ANY MICROWAVE
AS A EX- FIREMAN, I KNOW FROM FIRST HAND EXPERIENCE THAT
"A FUNNY SMELL " OR " UN-USUALL SMELL COMING FROM AN ELECTRICAL
ITEM IS A SIGN OF DANGER

hELLO THERE
when a microwave quits heating but every thing else is ok normally
investigate these 4 areas

Investigate these three areas if your microwave won't heat but you hear a loud buzzing or humming noise:
Power Diode

A diode is an electronic component that readily passes current in one direction only and blocks the flow of current in the opposing direction. If your microwave's diode has become defective, your microwave will not heat and you will hear a buzzing noise. Test the diode to determine if this is the cause of your problem. Replace it if it is defective.

• How to test a microwave diode.
• How to replace a microwave diode.



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High Voltage Capacitor

A capacitor is an electrical device which stores electricity. A defective capacitor may be why your microwave is not heating but you are hearing a buzzing or humming noise. The capacitor will have to be tested to determine if this is the cause of your problem. A defective capacitor will have to be replaced before your microwave will work again. Make sure you discharge the capacitor before you test it, though.

• How to test a microwave capacitor.
• How to replace a microwave capacitor.



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Magnetron

A defective magnetron is the third possible cause of why your microwave is not heating, but you can hear a buzzing noise. Test your microwave's magnetron. Replace it if it is defective.

• How to test a microwave magnetron.
• How to replace a microwave magnetron.

This more than likely is the magnatron,< heats food >, making noise and not working. it isn,t really easy fix and can be done if you get part and experienced person to walk you through it. Most GE magnatrons have at least 5 yr warranty and if it isn't that old call them first.

Check belt on fan.

All:
I have a 2003 Sears Ultra Wave microwave 721.63682300 with a similar problem. A few months ago it started giving off short buzzes when turned on. That stopped but then I noticed that everything took twice as long to heat up. After quite a bit of teardown&inspection I found a circuit break in the inverter board leading to ZD704 diode (pictured). I will now try to find a replacement diode to see if replacing will fix it. Thanks for your postings.

You either have a bad magnetron tube (5 or 10 year parts warranty item through GE Factory Service 1-800-432-2737 or www.geappliances.com) or a shorted high voltage rectifier. I think the light being out is a secondary problem.

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.

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 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 - The fan in my microwave oven is not running will this hurt my microwave?
A - YES, the fan cools the magnetron and electronics, take the microwave in for service, most fans are not too expensive to replace.
 

The noise is coming from the high-voltage transformer being overloaded by something shorting it out. Either the magnatron or the high-voltage capacitor and diode. Replace the capacitor and diode then if still not working, replace the magnatron. Its only affordable if you do it yourself - buy the part on EBAY - lookup "universal magnatron"
Hope ya fix it!