Microwave not heating and it is making a humming sound when it's on

The door switches are either faulty or not being depress when the door is closed, this usually means that the door and the cabinet are out of alignment

This louder, 60 cycle hum is usually caused by a bad magnetron. The unit will not heat when this happens. Repair cost can exceed $100.

The magnetron has gone and is the heart of the microwave oven, this part is the most expensive to replace, cheaper to buy new in the long run.

If the microwave is making a humming sound, then the diode is bad and needs to be replaced. If the microwave sounds almost normal but just not heating, then the magnetron is bad and needs to be replaced.

The diode that connects to the capacitor needs to be replaced. Once its replaced microwave will begin to heat again. (If it wasn't heating and wasn't making a humming noise, then your magnetron would need to be replaced). If you are thinking of doing it yourself and need instructions, i'll be glad to help.

sounds like same problem again.... the magnetron is what does the heating and if the display is working and just humming sounds like the mag is not coming on .... could be the capacitor but most likely the magnetron again..... i am a appliance /heating and air company out of texas we work on these things everyday and is very common problem... thanks a/c and heating unlimited good luck

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

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Possibly a shorted relay on the main timer board?? hum coming from transformer being powered with no fan running. With No fan you can hear it hum. shorted power relay on main board.

sounds like a crack in the magnetron
a bad transformer
or a bad rectifier
sorry i cant be more help

humming sound is your magneto going out Dont have any idea of the cost for replacement however it may be cheaper to purchase another microwave than to repair this one. Good Luck

Dave