• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

    Jake
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FIXED Frigidaire FFMV164LSA Microwave Humming Sounds

rrsas3019

Premium Member
Joined
Nov 2, 2019
Messages
6
Location
Baltimore
Model Number
FFMV164LSA
Brand
Frigidaire
Age
6-10 years
Hello,
I have a Frigidaire FFMV164LSA microwave that makes a humming sound (sort of like a refrigerator) when it's plugged in and the door is closed. The lights not working and it doesn't heat when I start it. Any help would be appreciated.

Thanks,
Ryan
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
38,220
Location
Murray, Utah 84107, United States
Sound like a bad door switch. Can you tell where the noise is coming from? Remove the top grill and the control panel screw on top That will give you access to the components and the door switches. Check the door switches by opening and closing the door. Be sure to remove the wires from the switch you're testing.
 

rrsas3019

Premium Member
Joined
Nov 2, 2019
Messages
6
Location
Baltimore
Thanks for the quick reply! It sounds like the noise is coming from behind the fan at the transformer. I disconnected the top door switch and it stopped making the noise. I then reconnected the top switch and disconnected the bottom switch and it still made the noise. Sounds like the top door switch could be the culprit?

Also, note that I previously said that it wasn't heating, but it in fact does still heat; I warmed a glass of water.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
38,220
Location
Murray, Utah 84107, United States
Sounds like the top door switch could be the culprit?
You'll need a DMM to check the switches. It may or may not be a faulty switch. Top is the primary interlock, the middle is the monitor interlock, the bottom is the door sensing interlock.
Snapshot_2.jpg
 

rrsas3019

Premium Member
Joined
Nov 2, 2019
Messages
6
Location
Baltimore
Here is a video that I took last night opening & closing the door. I'm not sure if it is helpful or not.
 

rrsas3019

Premium Member
Joined
Nov 2, 2019
Messages
6
Location
Baltimore
Ok, I tested the switches on the door again by opening and closing it with the same result as before.
I tested the thermal cut-offs and 1 of them was bad. Also, the humming sound is the microwave heating every time the door is closed.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
38,220
Location
Murray, Utah 84107, United States
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