Kenmore model number 721.80593400 everything works but will not heat food it also sounds louder. I just replaced the magnetron and that did not help any ideas.

Sounds like a bad magnetron tube.

What you are describing is a problem with the magnetron and it has become faulty, that is the main part that heats the food, the growling sound indicates it is loading down the power transformer that energizes the magnetron. The repair cost will not justify the expense "costly" replacement of the microwave oven "cheaper" in the long run.

When you say that the microwave won't turn on, can I assume that you mean that the food does not heat up! If that is the case, the problem lies with the magnetron circuit. This circuit consists of the transformer, rectifier and the magnetron, the part that generates the microwaves to heat the food. If it is the magenetron, then it probally not worth fixing since the cost to purchase the magnetron is almost as much as a new oven. To diagnose if it is the magnetron that has failed, when you turn on the oven, do you hear a louder that normal hum or buzzing sound? If that is the case, then it means that the magnetron is shorted and needs to be replaced.

Hope this helps.

To allow us to help you effectively (at no charge), please post a NEW problem to FixYa, and please include your brand name and the full model number from the tag in or on the unit, your symptoms, as well as the answers to these questions:

- When you try to microwave are the inside light, internal cooling fan and turntable all working?

- Is there any unusual noise or is it louder or quieter than normal?

(A loud buzz, hum, or groan is usually a shorted high voltage rectifier diode, but a sound like gurgling into an empty coffee mug is one symptom of a failed magnetron, and yet the mag can be bad without that sound.)

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

Note that a full Sears/Kenmore model number has 3 digits, a dot, then 8 more digits, such as ###.########

So we can help you, please post a NEW question, and please include your brand name and the full model number from the tag in or on the unit, as well as the answers to these questions:

When you try to microwave are the inside light, internal cooling fan and turntable all working?

Is there any unusual noise or is it louder or quieter than normal?

A loud buzz, hum, or groan is usually a shorted high voltage rectifier diode, but a sound like gurgling into an empty coffee mug is one symptom of a failed magnetron, and yet the mag can be bad without that sound.

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

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

My Kenmore 721.63259301 would not heat items up so I came here and saw the parts required and was just about to order them when I checked the online owners manual and found this. FULL FIVE-YEAR WARRANTY ON
THE MAGNETRON For five years from the date of purchase, if the
magnetron in this Kenmore microwave oven
fails due to a defect in material or workmanship,
Sears will repair it free of charge.
My microwave has a manufacture date of July 2009 so I will be taking it right to the closest Sears repair center for a free repair. I suggest everyone do the same.

Sounds like the magnatron tube or it's fuse.

It's magnetron, but you can test the high voltage trasformer, resistance of windings if to be exact.

Hi, this is common in most microwaves. this abnormal noise is coming from a faulty Magnetron. this device is responsible for the heating process and, it is damaged and not heating at all at this point.Simply replace the Magnetron and, this unit will start to heat once more.

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