All controls seem to be working - the oven just fails to heat anything

The signs are not always evident, but from the description the magnetron has failed.

There are several reasons the oven can stop heating. The most common is failure of the magnetron tube, which generates the microwaves. If you've been noticing longer cooking times, unusual humming noises or an electrical odor, these are signs of a magnetron nearing the end of life. When they finally fail, it's one of two ways. They open electrically like a fuse blowing, so that everything seems like it's working but there's no heat, like you describe. Or they can short-circuit, which causes a very loud humming or groaning noise and no heating, and may cause the main power fuse to blow so that the oven goes completely dead.

Unfortunately, the magnetron is about the most expensive part in the oven. So while it could be replaced, it's usually not economical. Between the cost of parts and labor (this kind of repair is best left to professionals because of safety concerns), it may only be a little more money to buy a new oven. In some cases, repair may even cost more than a new one.

There are other possible causes. There may be bad connections that have developed or something has gone wrong on the control circuit board. Other parts in the power supply for the magnetron may have failed. If you want to keep this oven, see what the cost is for a professional to check it over and give a repair estimate. It may turn out to be worth fixing. But if the magnetron is bad, it's probably time for a new oven.

Sorry I can't be more positive, but thanks for using Fixya!

The most likely cause of the clicking sound is the power relay that is connected to the microwaves PCB (circuit board) that turns the magnetron on and off. If starting to fail it may result in multiple clicks, then once fully failed, your microwave would simply not heat anything (as the high voltage components would not be getting power).
Unless you have a strength in electronics and repair, and understand the lethal dangers involved in working on a microwave, even one that is unplugged, this problem will likely need to be repaired by a qualified service centre.
Depending on the microwave design and the technician the whole relay circuit board may need to be replaced making this repair vary from relatively inexpensive to more expensive.

A defective diode or magnetron can cause the oven to sound differently and not to cook.

A microwave oven that runs but does not heat is typically but not always a high voltage component, usually a diode or magnetron. It could also be the relay on the control board.

Regardless of which component has failed I would strongly recommend leaving a microwave oven repair to a professional as the high voltage in them can kill.

Typically an in home repair would run about $200.00 for either of these failures.

I know this is not good news.... sorry

Sometimes there is a separate fuse for the magnatron circuit. Sometimes the fuse is the culprut, and sometimes it is the control board. Usually when magnatrons fail, they smoke or go bang or both.
I would look for a blown fuse first, and then look for a factory authorised service center.

Best of luck.

The Magnetron tube is what generates the microwaves that causes the heating.

If it runs but there is no heating then either the tube is bad, the overheat safety is bad, or the controller is bad. The tube and controller are both expensive and I suggest purchasing a new microwave instead of trying to repair it if the microwave is older. If the controller seems to be working for everything else then the tube is probably the culprit. You can take the unit apart (unplug it first!) and remove the magnetron tube and take it to a parts store for replacement. First check the safety (if your unit as one) and make sure it is closed (you'll need to ohm it out with a ohmmeter).

The tube usually goes bad when the oven is run without anything in it or there is a lot of reflective items in the microwave (i.e. metal, foil, etc) . What happens is the microwaves bounce around inside the cooking cabinet and never get absorbed by anything. So they end up bouncing back to the magnetron and heating it. The magnetron has metal in it. The tube then overheats and fails. The better microwaves will have a safety that shuts the magnetron down if it overheats.

If this helps you, please select YES to the first two ratings questions. Thank you, and Good Luck.

Hi, there are three issues that will cause a no heat situation in a microwave. these issue are a failed Magnetron, busted cut-off fuse and, failed diode.

I recommend checking all these area that are located inside the microwave for faults.

The most common issue will be a failed Magnetron.

The diode and, fuse will be located on the noise filter assembly.

Sounds like the magnetron has failed. This is the component that produces the microwaves that heats the food.

The cost of the magnetron is about 95% of the cost of a microwave oven. Most people don't, for this reason, replace the magnetron, they replace the whole oven which is probably what you will end up doing.

There is a possibility that the circuit that provides power to the magnetron is faulty and you need to take it apart, find the proper electrical leads and test them with a volt meter. To do this you have to remove it from its mounting and take it apart. It is a fairly lengthy process however.


Benjamin

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.