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Ask Randy Your Own Question
Randy, Home Appliance Technician
Category: Appliance
Satisfied Customers: 1300
Experience:  25 years of overall experience: Owner and technician of own appliance repair business.
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Buzzing Grinding Noise

Customer Question

Buzzing Grinding Noise
Submitted: 4 years ago via HelpOwl.
Category: Appliance
Expert:  applianceguy replied 4 years ago.

applianceguy : Hi, can you give me the make and model? Is the unit heating?
applianceguy :

Unplug each part one a

applianceguy :

Unplug each part one at a time. Start with the fan, then run it. If noise still there plug fan back in and unplug magnetron. Short out the cap and have the unit unplugged at this time.

applianceguy : this video shows you how to short the cap.

applianceguy :

Run unit with magnetron unplugged, see if noise goes away. If not unplug cap (short out first).

applianceguy :

The last part would be the transformer. So you are just eliminating each part as you go.

JACUSTOMER-kdc9t23r- :

the microwave is a GE SCA1000DWW03. Everything works just fine. Only problem is the noise. The noise occurs when I plug in the unit and set the clock, NOT when I start microwaving, so I do not think it is the magnetron or anything to do with the microwave circuitry. I have unplugged the magnetron fan and the noise still occurs. I am pretty sure it has something to do with one of the printed circuit boards, probably the relay board. I am going to try to use a hose to my ear and see if I can identify the noise source.

applianceguy :

I am unable to see your response, I do not know why. I will opt out so another tech may help you

Expert:  Randy replied 4 years ago.
Hello, my name is Randy and I am here to assist you if still needed. Okay, after looking at the diagrams and your symptoms, I agree with you. If you get a hum with NOTHING on then you need to replace the control board. Sounds like you have a bad transformer or relay on the board. You replace the board and you will be good to go. Thank you for your time and patience, Randy.
Customer: replied 4 years ago.

Randy, there are two PC boards in the unit, both expensive. I'd like to isolate the fault before spending hundreds of dollars on a parts swap to isolate the problem

Expert:  Randy replied 4 years ago.
I understand and yes there is 2 boards. The one I am referring to is called the "Smart Board". The onther board is just the button board which will send info to the smart board as to what button you have depressed. I am going to send you a link and the board that I am talking about is #1655 on the diagram. Again I thank you for your time and patience, Randy.