• ** 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 KHMC1857WSS0 Error F3H

David G

Premium Member
Joined
Apr 17, 2017
Messages
11
Location
San Diego, CA
Model Number
KHMC1857WSS0
Brand
KitchenAid
Age
6-10 years
The microwave heats fine in the cook mode, but when I try to use the popcorn or potato button error F3H is displayed. It seems the humidity sensor needs to be tested and perhaps replaced. I'm not sure how to access humidity sensor? I see it on a parts diagram, but none of the diagrams who how/where to access the sensor. Is it accessible from the inside or from the top?

Thanks,
David
 

David G

Premium Member
Joined
Apr 17, 2017
Messages
11
Location
San Diego, CA
Hi Rick,
Thanks for the picture. I removed the cover and found the sensor, which was by the fan. I wasn't able to test the sensor because all the wires terminals are contained in the part and the wires are contained in a braided sheath that runs to the plugin at the control board. I'll just go ahead and try a replacement part and see if that solves the problem.
Thanks again,
David
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
38,762
Location
Murray, Utah 84107, United States
Actually that is the test for that sensor. This is from the tech sheet:

Connect a new humidity sensor to the electronic control (at P1) then plug in microwave oven or reconnect power.

If no failure code appears when starting sensor function, unplug microwave oven or disconnect power and install the new humidity sensor.

If failure code appears when starting sensor function, unplug microwave oven or disconnect power and replace the electronic control.
 

David G

Premium Member
Joined
Apr 17, 2017
Messages
11
Location
San Diego, CA
Rick,

I replaced the humidity sensor and I no longer get an error when trying to cook with the sensor modes.

Thanks again for your help!
David
 
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