What Causes A Magnetron To Fail In A Microwave?

What causes a magnetron to fail in a microwave? There are a number of different reasons why this might happen:

  • Damaged magnets
  • Burned terminals
  • A samaged antenna
  • Loose connections

As with any electrical device, there are many more points of failure than the ones I’ve listed above! These are the most common reasons for a microwave magnetron to fail though.

In the rest of this article I’ll explain exactly why these issues cause so many problems for your microwave. I’ll also answer some related questions you might have on this topic.

Damaged Magnets

As the name suggests, your magnetron can’t do much without its fully functioning magnets!

If these become cracked or damaged, the strength of the magnetic field will be affected. That, in turn, reduces the heating performance of your microwave oven.

This damage often comes about from the magnet being placed under too much strain. This is most likely to happen if the magnetron becomes overheated, as is likely to happen if the energy reflects back into the magnetron.

Burned Terminals

Inside your magnetron is an insulator, which protects the device from the voltage of your appliance. If the insulator gets damaged, the magnetron terminal will also be affected.

As you continue to use the machine, this problem continues to get worse until – ultimately – the magnetron fails altogether.

Antenna Damage

Head over to Magsells and you’ll find a handy image that breaks down the individual components of a magnetron.

At the very top of the magnetron you’ll notice an antenna. That antenna is extremely sensitive, and if too much energy is directed towards it it can become burned.

Loose Connections

There are a number of connectors that fit on tothe filament terminals in a magnetron. If these become loose or damaged, a great deal of excess heat is generated.

As the connections weaken over time, you’ll notice your microwave producing less and less heat. Eventually, the magnetron will fail completely and your appliance will no longer work.

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.

Frequently Asked Questions

There are certain questions that often crop up around this subject. Here I’ll provide simple answers to the most common ones.

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!

Whatever you decide, I really don’t recommend replacing a microwave magnetron yourself. It’s always better to let the professionals take care of this sort of thing, even with the extra expense that involves.

How Long Does A Microwave Magnetron Last?

The answer to this question varies depending on:

– The make and model of your microwave.
– How heavily you use the microwave.
– The age of the appliance.

The generally accepted wisdom is that a microwave magnetron lasts for somewhere between 500 and 2,000 hours. Again it really depends on the microwave in question.

If that doesn’t sound like very long, consider how these appliances are typically used. They’re designed to be used for quick cooking and reheating, so in actual fact they can provide many years of good service.

What Causes A Magnetron To Overheat?

The most common cause of an overheating magnetron is when too much energy is reflected back into the device.

This can happen when you run your microwave empty (something you should never do), or if the turntable has been removed. 

If the turntable’s been removed, not only can the food not spin properly, you’re also removing a dense element that absorbs quite a lot of the energy during normal use.

How Do I Know If My Microwave Magnetron Is Bad?

Again, watch out for those key symptoms of a magnetron going bad:

– Poor cooking performance
– Strange noises
– A burning smell

These three symptoms can occur for reasons other than a bad magnetron, but these are the most common problems for this part of the appliance.

Wrapping Up

Now you know what causes a magnetron to fail in a microwave!

Watch out for those key symptoms of a failing magnetron, and be ready to act when they show up. 

A repair might make sense if the microwave is relatively new, but out of warranty. Leave the replacement job to a professional though, unless you really know what you’re doing.

Alternatively, it might just be time to start looking for a full microwave replacement! Nothing lasts forever, but hopefully you’ve got good use out of your appliance up until now.