Question about Kenmore 62622 Microwave Oven

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Kenmore microwave doesn't heat up

I recently purchased a kenmore microwave from an auction when I got it home everything worked fine time worked lite came on table turned but it wouldn't heat anything up. It sounded like it was working fine but no heat.

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Re: kenmore microwave doesn't heat up

I have the same microwave kenmore 721.62624200. I bought it 5 years ago and the same thing happened. It started humming and it's not heating. All of a sudden this just started happening. Is it worth fixing it?

Posted on Oct 24, 2009

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Re: kenmore microwave doesn't heat up

The most likely causes are a bad door switch, a loose connector on the magnetron, or a bad magnetron. If you or a friend decide to work on it, we have *critical* safety and disassembly info at our site, which is linked at our listing here on FixYa: Here's a reprint of one of our FAQS on the subject: Q. My microwave seems to be running okay, but it won't heat. A. If you are a do-it-yourselfer with the right equipment and care, you can do quite a bit of troubleshooting, but once you get near the high voltage section, it is time to be VERY sure of your actions. DANGER: Microwaves produce lethal voltages. They can kill. Before you go any further, you should read the safety warnings here: If you find line voltage (100-125 VAC) on the primary of the high-voltage transformer while the oven is running, the problem is indeed in the high voltage section. If that line voltage is not present, then the problem is not in the high voltage section. Door switches would be one suspect, as well as a control panel problem. To check door swithces, see this file: If you have or suspect control panel problems, see details of the repair service here: There are a few prime suspects to be aware of in the high-voltage section, mainly the high-voltage rectifier diode, the magnetron, and the high-voltage transformer. DIODE: Did the oven pop during the cooking cycle? If so, that's pretty good evidence that the diode has gone bad, not that's not the only way it can fail. High-voltage rectifier ID & diagnosis can be found here: MAGNETRON: Sometimes everything looks and seems okay, but the magnetron is simply not producing heat. At other times, it may be arcing inside, and producing a noise that sounds something like someone growling into a coffee mug. It's also possible that the mag may have a cracked magnet. Check for that, too. More likely, it may be that the magnetron filament connectors have loosened (they should be snug) and, due to resistive heat, the terminal connections have deteriorated and burned loose to some degree. A photo showing that area can be found here: . Here are some tips if you have loose connections: If the connectors feel loose, and any burning or melting seems minor, you should be able to carefully tighten the connectors with a pair of pliers, then sand or file the rusty-looking terminals of the magnetron until they are clean and shiny. If the burning is more serious, the connectors may need to be replaced. They can be obtained from home improvement centers and auto parts stores. They are 1/4" connectors and can be squeezed in place onto stripped wire with proper crimpers or a pair of pliers. Another option is to cut the connectors off the wires and solder the wires directly to the magnetron terminals. If this is done, do not apply heat to the terminals any longer than necessary. If the burning is really bad, the plastic surrounding the magnetron terminals is charred or melted, the magnetron may need to be replaced. HIGH-VOLTAGE TRANSFORMER: When the voltage transformer fails, it will often emit heat and smoke, but with the fan running, you might not smell it. With the cover off, it may be easier to smell. Also, you can look at the windings and see if they look discolored due to heat. If a high-voltage transformer is shorting, it can blow the fuse a few seconds after pressing the start button to start a cooking cycle. High-voltage transformer ID & diagnosis can be found here: HIGH-VOLTAGE CAPACITOR: The high-voltage capacitor will usually fail by shorting. When it does, the fuse will be blown right after you press the start button to begin a cooking cycle. If the capacitor is old and dries out, then it can fail by just not allowing the high-voltage to be doubled. I don't remember having ever seen this condition. High-voltage capacitor ID & diagnosis can be found here: More information on the high-voltage circuit can be found here: Again, be safe!

Posted on Feb 25, 2007

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Re: kenmore microwave doesn't heat up

Magnetron is shot----throw it away and buy a new micro

Posted on Aug 01, 2015

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1 Answer

My Kenmore microwave will not heat up anything. Everything else seems to be working fine with the microwave. Power, lights, ect.

Here is a tip that will help you to figure out what is wrong with yourMicrowave Oven....

Microwave Oven Basic Troubleshooting Tips


Aug 31, 2011 | Kenmore Microwave Ovens

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Our Kenmore microwave oven recently stopped heating. The lights, turning plate and controls all work but with no cooking is occurring. The last time I attempted to heat something up I heard a cracking...

The most likely cause is a bad magnetron, "heats food" the other two possibilities are the high voltage capacitor and diode. The cost to repair will a approach a new microwave oven.

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Kenmore microwave oven model # 721 63684300 built 5/2003. Does not heat, after 25-30 sec. F9 appears on keypad. Everything else works---timer, clock, lights, horizontal turnstyle.

I checked the owners manual and it does not list the fault codes. Manufactures leave this information out of the manual most of the time so you have to call them for service.

Call 1-800-4-my-home (sears) and tell them the problem. You will also need to provide the m# so have that ready when you call.

Good Luck

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Lost heat on microwave ,everything else works fine simple fix?

Inexpensive fix yes, but quite dangerous as you have to either replace the High voltage Diode or the magnetron depending on what has gone. Most often it is the Diode as that is fed a few thousand volts and anomolies such as a surge in current cause it to blow(popping sound) You can also check the fuses and if lucky it is just a fuse, but a fuse very seldomly just blows as it points to an underlying fault such as magnetron , capacitor or Diode. Have a service man attend to it unless you know what you are doing as you are dealing with lethal voltages and current even after the microwave has been switched off.

Aug 01, 2009 | Kenmore Microwave Ovens

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Sadly Kenmore only offers parts for 10 years. The truth is a new microwave for 50 dollars will be much more energy efficient than your 21 yr. old model

Jul 12, 2009 | Microwave Ovens

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Everything works except heat

this is something you should probably call a repair technician for, due to the danger of the componentry.

Usually in ther case of this problem, even a technician will advise you to replace the unit, in the minds of cost effectiveness and safety...

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Not heating

Hope you got a good deal, because you can replace all the microwave components for about $200.00.

It's going to be one of the following components -

1) Fuse
2) Diode
3) Capacitor
4) Transformer
5) Magnetron

Fuse is easily checked. If it's blown, replace with an identical type and rating. If it blows again, then dig deeper.

Diode is very hard to test, and cost is cheap. Replace it.
Capacitor is very hard to test under load, and is a little more expensive. Replace.

Transformer can be tested if you know what your doing.

Magnetron is not easily tested without harm to humans. Replace with same type or approved interchangeable equal.

Let me know your findings and I can help more if needed.

Jan 21, 2009 | Kenmore Microwave Ovens

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Disclaimer: I'm a DIYer, not a technician.

Our GE over-the-range microwave stopped producing heat yesterday while warming part of the T-giving feast. Everything else (fan, control panel, light) works fine.

After disassembly and testing last night, I discovered a defective "secondary door switch." Your Kenmore uses a similar switch (~$19 on-line), and that might be the problem. But it also could be other things, such as a bad thermal cut-out.

If you know anyone who's handy with a multimeter, most of the basic diagnostics seem to be pretty straightforward.

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