• ** 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 GT4175SPS2 Burned plastic smell

utnuc

Premium Member
Joined
Nov 12, 2016
Messages
5
Location
TENNESSEE
Model Number
GT4175SPS2
Brand
Whirlpool
Age
6-10 years
I just noticed that my microwave starting producing a burned plastic smell after it runs for > 1 minute. Reminds me of the smell when I blew a couple capacitors on a motherboard a few years ago. It still heats normally, light works and rotates normally. I assume I've got a failing part or wiring. How would you recommend proceeding to diagnose the problem? Is there a part that commonly goes bad in this way? Would it be best practice to just junk the microwave and go for a new one? The model is the built-in version, and I have the MK1170XPS trim kit surrounding it. If I'm going to replace it, how can I be sure this trim kit will fit the replacement?

Thanks in advance.
Ben
 
Last edited:

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
37,118
Location
Murray, Utah 84107, United States
That model is countertop microwave, here's the parts diagram: Parts for Whirlpool GT4175SPS2 Microwave

So you'll need to set it down on the counter to remove the cover. There's a screw on each side and then remove the screws on the back. Slide the cabinet straight back to remove it. Check the antenna on the mag tube and see if it's burned.
 

utnuc

Premium Member
Joined
Nov 12, 2016
Messages
5
Location
TENNESSEE
There's a discoloration on one side of the mag heat sink, but the antenna looks good. Other thoughts?
DSC_2489.jpg DSC_2490.jpg DSC_2493.jpg
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
37,118
Location
Murray, Utah 84107, United States
If that burn spot is from the mag tube, that's the problem. Measure the resistance of the tube and measure from each terminal to metal body (ground).
 

utnuc

Premium Member
Joined
Nov 12, 2016
Messages
5
Location
TENNESSEE
I'm getting 0 resistance across the terminals (although my meter is only 1kΩ) and open circuit from each terminal to ground. That's gotta be normal.

I visually checked all capacitors on the control panel and the other boards and they look normal.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
37,118
Location
Murray, Utah 84107, United States
Look for any signs of burning or any discoloration on the other parts and control board. Try running it with the cover off and maybe you can tell where it's coming from.
 

utnuc

Premium Member
Joined
Nov 12, 2016
Messages
5
Location
TENNESSEE
Thanks, I found a poor connection on the door latch switch that was arcing and corroded the contact. I've sent off for a replacement latch and will put a new disconnect in place. Thanks for the advice.

Ben
 
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