GE JVM1640 Microwave Oven Logo
Anonymous Posted on Aug 23, 2007

No heat - where is the diode

JVM1640AB002 mfg Feb 2000, kw= 1.58 SN DZ996205S This failed with a single buzz arcing noise (buuzzzzz-IT-ARC...SNAP! sound) similar to having a piece of metal arcing in the cooking area - but no arcing in the cooking area and no metal. It arced three times, once when it failed heating, twice after a restart, each time, no heat. Now no arcing or heat. No popped circuit breakers, just does not heat. Everything else works, display, fans, lights, turntable. I have tested the door switches, they function correctly. Reseated the connector on the magnetron, checked for broken insulation on wires, tapped the on board relays a few times Where can I get a schematic to locate the HV diode and check it before I locate a new magnetron? Or, is it even worth getting a new Magnetron? I mean, these are running for about $200-$300 retail. Thanks!

  • 4 more comments 
  • Anonymous Aug 24, 2007

    I found the diode, and the price for the magnetron with new diode is $150 online.

    So I'll test the diode and if bad, look for the part number because that sucker with a piece of shrink wrap, a ring lug and spade lug is $50 ! Crazy ...

  • Anonymous Aug 24, 2007

    Gee, the buzzzzz-IT_ARC ... SNAP was probably the diode that had shorted then opened. If functioning properly, it was acting just like a fuse.
    The diode is an HVR-1X3 High Voltage Diode. $0.79 from most electronic dealers, $5.00 with the ring and spade crimped on as Microwave Ovens and TV's commonly use these.

    And Appliance dealers charge $50!!

  • Anonymous Aug 24, 2007

    With the help of this site, and, all tests are complete, HV xfmr is fine, magnetron preliminary checks okay, capacitor okay, door switches all check out.
    So it looks like the cost of the repair will be less than $5.00 and an hour of labor on a $300 appliance.

  • Anonymous Sep 28, 2007

    Actually when testing the diode, you need to use a megohm meter. You can not test a HV diode using a standard meter.
    The diode was good after testing with a megger, HV Transformer supplied a nice arc and filament voltage, so the last thing in the basket was indeed a bad magnetron.
    Magnetrons can be had for about $51 if you simple Google the part number on the Magnetron. This means some appliance stores are marking up parts in some cases 200%, with the more reputable appliance guys only marking up 25% which is a bargan considering they give phone time advice for free.
    Magnetron replaced for $69, all is well.

  • Anonymous Mar 26, 2014


  • Anonymous Apr 01, 2014

    Two Microwaves at work failed at the same day. The keypad/display works on both units but neither unit will heat food. I took the cover off of one unit and tested the
    hv diode, the capacitor, the door switches and the heat sensor on top. All were good. I visually inspected the Magnetron and it appears ok. No cracked magnets or burned insulators.
    Anything else I can check?



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William Miller

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  • GE Master 9,179 Answers
  • Posted on Sep 28, 2007
William Miller
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Joined: Sep 15, 2006

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My galanza microwave, air fryer, oven will not heat while using microwave and makes a terrible racket?

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.


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Samsong microvave does not heat, increase buzzing noise

You may have failing magnetron or shorted high voltage diode, but on some models, it is a failing capacitor on the controller.

We would need to know the full model number from the tag in the cooking cavity or elsewhere on the microwave, such as the door frame, controller frame, etc.

Please post a new help request with that and more detailed symptoms.

Roommate steamed up the spacemaker by hard boiling pot of soup without running the fan. Then microwaved a cup of coffee while the steamed condition was still present. An arc sparked from the vent above...

Sounds like a problem in the high voltage side. Need to check the diode and if good the voltage at the magnetron. Should be 3.5 volts across mag and 4500 dc volts at mag. If you do not have a meter to check replace both mag and diode aprox $150.00 from GE. Pat

Microwave won't heat, light ,clock works the microwave just won't heat the items in it.

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:
microwave_diode.jpg 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.

picturena.gif 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.

microwave_magnetron.jpg 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.


Started arcing inside like it was on fire. It started to arc inside and making a loud noise. You could see big flashes coming from inside where the motor is. It did'nt last very long. I wont be buying...

When the micro starts arcing it is reasonably serious. One or more of the components are broken down. What needs to be done is firstly, "pull the plug out" The cover needs to be unscrewed and removed. You will then see the electrical components on the R.H.Side. There is a magnatron (creates the heat).and a capacitor (discharge voltage) and a HV diode. (DCcurrent to charge the cap). The magnatron needs to be replaced, and the HV diode. Please do not do it yourself as there are lethel voltages sitting there waiting for a wrong move. A technician needs to do the repairs as he has the appropriate tools to discharge the cap and do relative tests.

Panasonic Microwave NNSD277B 5yrs old makes noise after 20sec on (bUzzing and popping)and internal light flashes. Should be replaced or fixed ? what could be the problem?

You should have no arcing within the unit. Assuming you have adequate food/water in the cavity, it should not arc. You NEVER run the unit without something to be heated in it!!!

You might check the stirrer fan which is often in the roof of the unit to see if contamination might be in the area causing arcing. The electric fields in th area are very high and arcs can jump.

If the insulating window is charred or has charred grease, it should bbe replaced.

Microwave making loud buzzing sound when operated, sounds like something is about to pop.

could be several possible components at fault. how old is it ? does the unit heat ? if so, could be a hi voltage diode, or a hi voltage tranformer. (older frigidaire m'w's had trans. that would crackle and "arc" when bad) it is not the mag though, it wouldn't heat if so.

Microwave made loud popping sound and now does not heat.

Try this
Probably a high voltage diode popped because contaminated grease eventually built up and made a path for a high voltsge arc to occur.. To confirm,take the outer cover off the microwave and discharge the high voltage capacitor by shorting its terminals. Then pull the plug off the magnetron side and place it near the magnetron socket. Now turn the microwave on and push the connector on the magnetron with a chopstick or a long insulated screwdriver. If no arc when you do this this confirms a bad diode.

please rate my suggestion..

Kenmore 721.80524500 makes a buzzing, grinding noise

Your problem is due to the "magnetron" arcing to the wave guide within the microwave. Picture someone arc-welding stuff together inside the microwave casing, that's essentially what's happening. It is a fire hazard and you should stop using the microwave immediately. As far as I know, there isn't a recall on that particular model (though there was on another similar Kenmore/Whirlpool model) so if it's out of warranty, you're out of luck.

Kenmore 721.63662300, 1200W

The magnatron is shorting and overloading the high voltage transformer which is complaining with a load noise. Worth fixing if you do it your self. Magnatrons cast about $40 wholesale. There are just a few varieties of them that fit almos all brands. Try
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