Question about Sanyo Microwave Ovens

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Why do Magnetrons fail? I ask this question as my microwave (2 year old integrated microwave) had a Magnetron failure. Was cheaper to replace it. Got a new integrated one (different brand) and a week into use the Magnetron has failed in it. Seems to much of a coincidence for me. The area is dry and I have no problem with any other appliances. In both microwaves the grill, timer etc was still working. Seemed like it was working but no heat in the food. The company has replaced this new one with a Sanyo but I am nervous to put the replacement in just in case there is something wrong with the environment that is making the magnetron fail. Any suggestions or just a coincidence? Thanks Sue

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I have checked the Magnetron, it had a zero ohm reading, changed the fuze again, powered the unit which is a Sharp carousel convection microwave oven model R-9Z00, all lights came on tried the oven on cake setting the heater came on to warm the oven, but as soon as the the magnetron switched on, Boof the fuze blew again.
Yeas I agree I will buy a new Microwave

Posted on Mar 25, 2013

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The magnetron is supposed to read nearly zero ohms across the two terminals. Those are the heater terminals. It should read infinite resistance between those terminals and the case.

Magnetrons failure is caused by either the heater opening up, or insufficient emission of electrons from the cathode (heater). Failure is accelerated if the oven is run empty, or nearly empty (popcorn or other low water content foods).

Posted on Apr 22, 2017

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Say coincidenc

Posted on Nov 02, 2012

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Posted on Jan 02, 2017

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SOURCE: microwave will not heat food

Found this under Maytag instead of LG, but will be happy to help.

Generally, the most common causes of a failure to heat are:

- bad door switches or door switch mounts
- loose connection at the magnetron
- problem or loose connection on the control unit circuit board
- bad magnetron or other high voltage part

If you or a friend decide to look into it, we have critical safety information, info on door switch diagnosis and replacement, and disassembly information at our site, and our link is at our listing here on FixYa:

Magnetron diagnosis is here:

We're happy to help and we appreciate your thoughtful rating of our answer.

Posted on Dec 08, 2007

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SOURCE: GE Profile JE1660GB01 magnetron failure?

It pass the resistance tests and still be bad, and I suspect it is.

I would also suggest that you check the high voltage diode to be sure it's not shorted.

If the filament voltage and high voltage are both present at the magnetron terminals, and not loaded down, but there is no heat, then it's the magnetron.

As a pro with over 20 years of expereince, I have always measured the high votlage, but I will never recommend it to a non-professional. Without the right equipment and procedure, you and your equipment can be "fried". No kidding.

Here are some good links to safety & troubleshooting:

We're happy to help and we appreciate your thoughtful rating of our answer.

Posted on Dec 31, 2007

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SOURCE: F9 error

Your Microwave uses "UltraWave technology"
I'll explain a few things about this wonderful technology...
The control board (accepts the pushbutton commands) has to talk to the inverter board to tell it how much power should be applied to the magnetron. The inverter board will then power the magnetron and inform the control board if the magnetron is working OK.
If there is something wrong with the magnetron or inverter board or a there is a communication breakdown between the control board and the inverter board...WA-LA-----F9----

A pretty reliable test for the Magnetron is to operate the oven and listen for a ticking sound 5-6 times about a second apart. If you can hear the ticking....The magnetron has failed..if no ticking, the control or inverter board failed.

The Magnetron sells for about $78.00 and is simple to replace. Check your owners manual for limited warranty on the MAG and electronic parts.

Posted on Jun 12, 2008

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SOURCE: GE microwave replacement magnetron

I also have a HotPoint (GE) Spacesaver Microwave Oven (MWO)that we got at Home Depot about 3 yrs ago. The magnetron quit yesterday and I found out online that this is a common occurance with GE MWO's. I found this string and thought I would attempt to have GE send me a magnetron to replace the defective original part.

I called Customer Relations (1 800-386-1215) and spoke with Nikita. I informed her nicely that I was aware that this is a common problem with GE MWO's and that I am a Union Electrician who would like to perform this repair myself. I simply needed the replacement part. She was very understanding and asked for the model and serial number and after a few minutes she supplied me with an order confirm #.

The part should arrive in a few days via FedEx and we will be back into space age cooking and also our appliances will still match. Thanks to all who posted to this string and clued me in (You have saved me a C note!).

David in Omaha

Posted on Jan 14, 2009

  • 17 Answers

SOURCE: Microwave Magnetron tube has arced


Posted on Feb 08, 2009

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1 Answer

Our microwave will turn on but will not heat the food or water

Magnetrons in microwave ovens do not last forever, and are subject to failure from power surges. When the microwave oven no longer heats food, it is likely that the magnetron has failed.

May 09, 2015 | Microwave Ovens

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I have a GE Spacemaker Over-The-Range Microwave Model #JVM1533WD002 that has worked perfectly for 10 years. Now everything still works, except it doesn't heat the food. Where is the fuse located and how...

A common symptom of a failed magnetron is a failure to heat with everything else (magnetron fan, stirrer, timer, etc.) working fine. Check the GE manufacture date for the unit on its nameplate to determine the age of the magnetron. For GE models of the past, magnetrons had a 10 year parts replacement warranty. Magnetrons can be expensive, so you need to weigh all your options, i.e., repair versus replacement, before you commit to one solution.

Oct 04, 2013 | GE Spacemaker Over-the-Range Microwave

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I have an Electrolux High Speed Oven E30SO75FPS that's 3 years old and the Magnetron has failed for the 3rd time. What can be causing this?

Is the internal cooling fan working?

Are the ducts and vents clear?

Problems with any of those can result in overheating, which destroys magnetrons.

I have seen high voltage rectifier diodes interact with magnetron in funny ways. I'd replace the diode, too.

You can find links to helpful exploded view diagrams and part ordering help here.

I recommend that you bookmark that link to your favorites.

Finally, baking potatoes and making popcorn really give the magnetron a workout.

You should put about 1/2 cup of water in the rear corner of the microwave when cooking those foods.

It helps "preload" the oven to prevent execessive microwave energy reflection back to the magnetron.

happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

Dec 12, 2011 | Microwave Ovens

1 Answer

It runs but no heat

common probelm with microwaves if everything is working on unit with the exception of the heat itself... then it is very possible the magnetron or the thermal fuse to the magnetron has failed... usually yoiu can access this behind the control panel/control board assembly and test with a volt meter ... the magnetron is what does the heating and is common failure based on your description of problem.... if it is magnetron then the cost is sometimes high to have replaced and will have to be weighed into option of replacement.... most magnetrons have a 3-5 year warranty so it may be beneficial to have a servicer look at it if still under warranty and you may only be out labor cost
good luck to you .....

Jan 20, 2011 | Frigidaire PLMV169DC Microwave Oven

1 Answer

Model MS 2327 B, works but is not heating up anything

This is a very common fault on microwave ovens and is usually caused by a failed magnetron. This is the device which produces the microwaves and it is the single most expensive component. Magnetrons don't really have a fixed lifespan, they can last for twenty years or more or can go pop the first day they're used.

Replacement is usually straightforward (make sure to obtain a new microwave collar as the old one cannot be re-used safely) but rarely cost-effective. Unless the oven remains under warranty it's always far quicker and usually much cheaper to replace the oven, especially as yours is a budget model.

Sep 10, 2010 | LG LMV1680ST Microwave Oven

2 Answers

Microwave turns on but will not heat up

The problem is that the magnetron circuit has failed. It is the magnetron that generates the microwaves to heat the food. Typically the magnetron shorts out. The symptoms is that when it is on, it creates a loud buzzing noise when it is shorted. The cost of the replacement magnetron is almost as much as the oven, and not cost effective to repair.

Jun 30, 2010 | GE Microwave Ovens

1 Answer

Oven won't heat food

Bad Magnetron. Unfortunately, and especially on high power microwaves, magnetrons do die. They'll probably run you between 100 and 300 dollars to replace. If you believe that your microwave is within warranty(not likely), contact the manufacturer for repairs. Otherwise, it may just be cheaper to purchase a new microwave.

Sorry that this answer doesn't produce a happy result, but it's an unfortunate fault of microwaves as a whole.

Apr 23, 2010 | Maytag MMV5186A Microwave Oven

1 Answer

My microwave oven isn't heating my food. Everything else works, the fan, the lights and the keypad. The microwave turns and sounds like everything is working but the food won't get hot. It is only 6 months...

This is typical of a failed magnetron: the part which actually supplies the microwaves.

By their very nature magnetrons can fail without warning from the day of manufacture but the vast majority do last longer than the manufacturer's warranty. I have noticed a trend towards more frequent premature failure with increasingly powerful ovens.

If the magnetron has failed then there is nothing you can do to fix this as it must be replaced. It's also typically the most expensive single component in most ovens so is rarely an economic repair.

Your appliance should still be within the manufacturer's warranty so you should follow their advice regarding getting the oven repaired. If you're in the UK then you have Sale of Goods Act protection for up to six years from the purchase date and if you wish can insist that the retailer replaces the oven or refunds your money as the goods were not "of satisfactory quality".

Oct 16, 2009 | Maytag MMC5000 Microwave Oven

2 Answers

Microwave won't heat

Sorry my Clarification Request came out as a single blob of a paragraph.

That's not how I typed it. I never write that way!

So I've pasted it here, but as a solution.

Magnetrons generally should last about 2000 hours, but several factors can shorten that.

If it's not OVER ten years old (from the purchase date or the date on the tag inside the unit) then the magnetron is still under warranty.

From the owner's manual:

"For the second through the tenth year from the date of original purchase

"The magnetron tube, if the magnetron tube fails due to a defect in materials or workmanship. During this nine-year limited warranty, you will be responsible for any labor or in-home service costs.

"For the above limited warranty: To avoid any trip charges, you must take the microwave oven to a
General Electric Customer Care® servicer and pick it up following service. In-home service is also
available, but you must pay for the service technician’s travel costs to your home."

GE Customer Service is here, and you can verify the warranty status and find your nearest authorized servicer.

If you're sure the magnetron's bad, it's still under warranty, and you or a friend are handy, they will send you the magnetron to do it yourself. Call them at 888-239-6832.

Be persistent. You may have to speak with a supervisor.

It does sound like the magnetron overheated and the magnetron's thermostat opened until it cooled down.

An overheating magnetron can be due to:
  • operating oven without cover(s) in place
  • wrong magnetron installed in oven
  • an old or otherwise failing magnetron
  • cracked magnetron magnet
  • improper power line voltage (should be 110-125VAC)
  • foods low in moisture (popcorn & bacon, e.g. - add 1/2 cup of water in rear oven)
  • failed or inoperable cooling fan or hood vent exhaust fan
  • deteriorating foam weatherstripping seals in air ducts or on outside cover
  • blocked air vents (dust, animal nest debris, insufficient free air space behind & around oven, etc.)
  • clogged or greasy charcoal filter or grease filter
  • blocked duct in hood vent exhaust
Since yours is a counter top model, there are less of those factors to worry about.

When you hit Start to microwave, do the inside light, cooling fan, and turntable all come on?

Any unusual noises? Is it louder or quieter than usual?

We have a sound clip of what a microwave should sound like when the cooling fan and high voltage section are operating here.

You can find helpful exploded view diagrams and order parts if needed by entering your full model number from the tag on the oven here.

Let us know what you find out or decide.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

Jul 05, 2009 | GE Spacemaker JVM1640SJ Microwave Oven

1 Answer

Oven runs but does not heat

This is going to be either the high-voltage transformer, the magnetron, or the high-voltage diode. Magnetrons are the mosty common failure in these, and there is a campaign underway to replace "underperforming" magnetrons. To see if yours is one of these, visit:

Apr 05, 2007 | GE JE1640WA/GA Microwave Oven

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