Stopped heating
If everything works, but the microwave oven does not heat, this is commonly caused by a failed magnetron. The magnetron is the heart of the oven that produces the RF energy that is used to heat your food. In order to replace a defective magnetron, you will need to consider the following:
1. You will need to uninstall the oven from over the range in order to replace the part (you will need to do this anyway, if you decide to buy a replacement oven).
2. Ensure the oven is UNPLUGGED before servicing anything inside the cabinet and remove the exterior case in order to access the magnetron. There are several websites that you can use that illustrate how the oven is assembled:
searspartsdirect.com
pcappliancerepair.com
appliancepartspros.com
NOTE: If you've never repaired an appliance on your own before, a microwave oven is usually not a recommended appliance to start with. Some models can be rather involved in taking apart.
3. The magnetron replacement part number for the model you have listed is 2B71165R and is listed as item 5009 under the Internal Parts I listing. The average cost is about $70.
If you microwave oven does not run at all, the likely source of the problem is either a blown line fuse or AC line filter board. The line filter and fuse are accessible by removing the exterior case. The assembly is located at the point where the power cord enters the oven. The filter board is listed as item 5041 under the Internal Parts II listing and the line fuse is listed as item 5001. The part number for the Line Filter board is EAM35001801. The part for the fuse is 3B74133Q. You can usually purchase an entire box of fuses at your local hardware store for a better price. 125V, 20AMP, slow blow fuses are recommended.
This model also has a thermostat (bi-metal) that if tripped, will also cause the oven not to heat or run. The thermostat acts as a fuse if the magnetron overheats. The part number is 6930W1A003E and is listed as item 5016 under the Internal Parts II listing. You will need to remove the thermostat from the oven and take a resistance check across the component terminals to determine if it is good or not. A low resistance reading indicates a good thermostat. An infinite reading, indicates a blown thermostat and needs to be replaced. If the oven cavity has overheated, it can sometimes trip the thermostat. Some of these thermostats will reset themselves when cooled down, some do not. Items such as baked potatoes, steamed vegetables and pop corn can often cause the oven cavity to overheat if the cook times are long, or if you cook several itmes in rapid succession. Its best to allow the door to stand open and the oven cavity to cool between cooking any food that make give off steam.
Review the parts illustrations at the recommended websites to see if this is something that you may be able easily take apart and reassemble.
If you have any questions, please post back and let me know. I hope you find this information helpful.
NOTE: If your model number is not listed at all the websites I have listed, use the part numbers from the Sears site to cross reference. In many cases, the model number may not cross reference to all websites, but the part numbers will.
CAUTION: DO NOT operate a microwave oven with the exterior cover off. The voltage inside the High Voltage network where the magnetron is installed can exceed 3,000 volts!
