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?

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: http://tinyurl.com/yzjozk 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: http://207.234.249.73/mwd/safety.txt 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: http://www.microwavedisplay.com/doorsw.txt If you have or suspect control panel problems, see details of the repair service here: http://207.234.249.73/mwd/index.htm 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: http://www.gallawa.com/microtech/diode.html 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: http://207.234.249.73/mwd/magterm.jpg . 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: http://www.gallawa.com/microtech/xformer.html 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: http://www.gallawa.com/microtech/cap_test.html More information on the high-voltage circuit can be found here: http://www.gallawa.com/microtech/doubler.html Again, be safe!

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