Microwave Quit heating

My 12 year old microwave quit heating today. I was warming some soup and set it for the required time. When the cycle ended, the soup was warm, but not hot. I ran the MW another minute and the soup did not get any warmer. I tried yet another minute. It never got hot. The MW runs, the timer works the platter rotates, but it just dont heat. I noticed that it makes a loud hum, much louder than it did before.

I suspect that the heating element burned out, and probably costs more for the parts to repair it, than to buy a new MW. But I thought I'd ask if there could be something else that failed?

Is it normal to make a loud hum when they fail?

Reply to
homeowner
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The tube that generates the microwaves is called a Klystron. It looks a lot like a regular vacuum tube you might have seen in an older TV set. Anyway, the Klystron can fail in two ways. 1, It actually burns out and you get no heating at all, 2, it gets weaker with age, and heating times gradually increase. A third possibility is that some other component in the uwave has failed.

Since you got some heating, and then it seems to have stopped heating, we can pretty much eliminate the gradual failure. Only someone familiar with mucrowave ovens can tell if the Klystron or some other part has failed. And, you are right, the cost of repairing it can be more than the cost of a new one.

So, you have to tell us a lot more, such as make, model, age, appearance, etc, before we can advise you what route to take. Have you tried to heat some cold water again? Was there any heating?

Reply to
hrhofmann

Hi, Do you mean Klystron or Magnetron?

Reply to
Tony Hwang

It's the Magnetron. 9 times out of 10 that's the problem when it stops heating.

Reply to
Meanie

They are magnetrons Klystrons are sometimes excited by Magnetrons for very high powered radar systems - the klystron is the amplifier.

Reply to
clare

Hi, Yup, I used to work on TWT exciter-10KW Klystron-100KW Klystron drvien triple diversity troposcatter system B4 the days of satellite took over. Also worked on MW comm. system putting out 3-5 Watts from a small Klystron. Long time ago in the late '50s-'60s.

Reply to
Tony Hwang

Most of the time the diode shorts or cap, or transformer shorts. I think with no load, the transformer still sucks a lot of power. There should be small resistance between magnetron terminals, on heater. Always discharge cap !!! If it's simple like diode, replace part, but you will spend too much on other parts except cap.

If yo want full info, check out science repair FAQ. Microwave ovens.

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Greg

Reply to
gregz

Sounds like a failed high voltage diode. Easy repair. Diode goes between the high voltage capacitor, and ground. Electrical safety rules apply, as do legal disclaimers.

Christopher A. Young Learn more about Jesus

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I suspect that the heating element burned out, and probably costs more for the parts to repair it, than to buy a new MW. But I thought I'd ask if there could be something else that failed?

Is it normal to make a loud hum when they fail?

Reply to
Stormin Mormon

I must work on the wrong units. The ones I've repaired, have been bad diode (several), or capacitor (one).

Christopher A. Young Learn more about Jesus

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It's the Magnetron. 9 times out of 10 that's the problem when it stops heating.

Reply to
Stormin Mormon

Magnetrons are quite tough, most failures are due to the the diode, capacitor failing or simply a blown fuse. ^_^

TDD

Reply to
The Daring Dufas

You're right. Besides, like an old car, you fix this and then that fails. Also, probably the newer ones are safer and more efficient tho I'm guessing since I'm using one about 14 years old myself. I just told my wife that we better prepare to replace it soon as I see it beginning to rust inside.

Reply to
Doug

The fuse has always been the problem with my microwaves, Radio Shack and other hardware outlets always have them available, a cheap test is to replace it.

Reply to
EXT

almost always shorted diode when it hums.

Reply to
mike

ews:kcda41$9ll$ snipped-for-privacy@dont-email.me...

But the fuse will take out more than just the heating function, the whole unit will fail.

Reply to
hrhofmann

messagenews:kcda41$9ll$ snipped-for-privacy@dont-email.me...

There may be more than one fuse. ^_^

TDD

Reply to
The Daring Dufas

Which can also cause the fuse to blow - - -

Reply to
clare

This one has been rusting quite a lot where the wheel rotates the platter inside. I was planning to coat that rust with some sort of paint or epoxy. It's a General Electric. I've heard that this rusting is a common problem with these GE MWs. I'll check it out. If it's a diode or cap, I'll fix it, otherwise I guess it's time for a new one. If I junk it, I'll save the timer. I've known people to use them to turn on lights for a brief amount of time, and other uses. That's assuming its separate from the other components. The original MW's had a separate timer.

Reply to
homeowner

That is quite an article. It seems to have everything anyone would ever want to know about fixing a microwave. I have not read all of it, but I've already learned a lot.

One thing, the article has invalid links. I suppose they are old.

Both links here (Below) are obsolete -

*Microtech maintains a web site with a large amount of information on microwave oven repair including an on-line

*Tech Tips Database with hundreds of solutions to common problem for many models of microwave ovens. There are also an extensive list

Reply to
homeowner

Tec tips used to be very popular with things, like monitors, vcrs, etc. I'll see if I remember to send Sam a note. All the mirror sites should have the same edition, Including mine.

Epoxy paint should work well, with prep.

I've installed mechanical timers before. Some people like them better.

Greg

Reply to
gregz

Mechanical timers live thru noise on the power line much better than electronic timers. Also sorry about Klystrona vs Magnetrons in my original response. Thinking radar power levels, not home ovens.

Reply to
hrhofmann

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