My microwave has a hole burned through the door.

That's actually a mica "window" (cover) for the microwaves to come out. And it sounds like the magnetron started arcing and burned a hole in that cover. Either that, or some food (frequently spaghetti sause) got splattered on it, and the microwaves heated it up so much that it burned a hole in the cover. Does the microwave oven still work (heat)? Do you see or hear any arcing? If the microwave oven still works and there is no arcing, you can just replace that cover. Check SearsPartsDirect.com or RepairClinic.com.

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If your positive it is not arcing behind the waveguide cover I would think it has to be in the control area. You will have to turn off power to the unit and remove the control panel and look to see if you can find any burn marks or soot, to indicate where your problem may be. I have found burnt connectors at the relays or even possibly burnt wires to the door switches. Careful! the capacitor on these can hold a charge for a long time and can shock you pretty good. Only work on something like this with the power to it off and the capacitor discharged. Microwaves do not come through the little round holes those are typically an RF screen to prevent microwaves from getting through. A lot of times that is where the cavity lamp shines through.

Yes you are right! the magnetron has gone and produces a odour that is very distinctive when this happens. The fact you got 30 years out of it is excellent and yes it is time to replace.

Hi,

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

Basic Microwave Oven Troubleshooting Tips

heatman101

check the safety switch for complete door closure.

Check the door safety interlock switches.

Do you regularly shut the machine off by opening the door? Each event causes a small arc on the tiny contacts and will burn them. When they can no longer make contact, your microwave doesn't know if the door is open or closed. The machine must know the door is closed to turn in the magnatron (that thing that makes the heat).

Remove the cover and check the microw switches with a volt/omh meter.

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Disconnect the connector to the primary winding of the high voltage transformer. Put a new fuse . If the fuse is not blowing the problem may be in the secondary side of the high voltage transformer. Chek the highvoltage diode, capacitor, magnetron respectively. you can also check the primary winding of the low voltage transformer.

This is usually caused by either exposed metal in the micro, or the metal in the bag of popcorn was overexposed. Typically if this happened, replacing the door components costs around 20-50 bucks. Which in, in any case, if the unit is over 2 years old or older, it would be more fesable to replace the unit.

If it's less than a year old, it's under warranty and you should call the nearest Sears store for free repairs. Quite often this is due to a bad door switch. Opening the door while cooking (without first hitting the STOP pad) is the primary cause of door switch failure. If you or a friend decide to work on it, we have *critical* safety, disassembly, and troubleshooting info (as well as a text file which helps in diagnosing and repairing door switch problems) at our site, which is linked at our listing here on FixYa: http://tinyurl.com/yzjozk You can find helpful exploded view diagrams and order parts by entering your full model number here: http://www3.sears.com (the 3 is correct)