• ** 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

KEMS379BSS01 KitchenAid microwave isn't working. Tray doesn't turn and Timer freezes.

gstide

Premium Member
Joined
Aug 18, 2019
Messages
5
Location
wa
Model Number
KEMS379BSS01
Brand
KitchenAid
Age
1-5 years
Hi guys,

I have a KitchenAid Microwave/Oven combo. Model# KEMS379BSS01

The problem is:
  • the microwave doesn't work. It can't heat the food.
  • the tray doesn't turn.
  • the timer count down one second and then it stops.
  • after all these, the microwave continues to stay on for sometime then stops and show:
    • Err F1E5
      MW Inverter
I replaced the Inverter. But it didn't help. Nothing changed. All symptoms are same.
I saw some threads in this forum and other websites. Nobody seems mentioned the tray and the timer issue. So I'm wondering if I should try replace the control board W10577815, or try a new magnetron? Any further diagnose I can do before ordering new parts?
I'm new to repairing appliance, thanks a lot for the help!
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
1,910
Location
Canada
gstide said:
Any further diagnose I can do before ordering new parts?
There should be a 'tech sheet' in the unit with its wiring diagram to help diagnosing problems. Here's a PDF version.


It suggests testing the thermisters for readings and connections. If those test as Ok, the control might need to be replaced.

LINK > W10915648 Replacement Control PCB for W10577815

gstide said:
I'm wondering if I should try replace the control board W10577815, or try a new magnetron?
A failure of the magnetron tube should not affect operation of the turntable. It is unlikely to be the cause if both functions failed at the same time IMO.

Dan O.
 
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gstide

Premium Member
Joined
Aug 18, 2019
Messages
5
Location
wa
Thank you Dan
Finally I got a new meter to check the thermistors.
I'm new to this. So I'm not 100% I did the measurement correctly.
So, when the tech sheet says "check resistance of the thermistor", I should check the pins on the wire, not those on the board, correct?
If I did it right, the resistance is very close to the numbers from the tech sheet.

The tech sheet also says "check thermistor for short to ground". How do i do that?
what I did is I measure the resistance between the microwave shell and the pins. Both pins show infinite. So I guess they are not short to ground?

IMG_0010.jpg
 
Last edited:

gstide

Premium Member
Joined
Aug 18, 2019
Messages
5
Location
wa
Correction:
P21 is Magnetron thermistor
P22 is Cavity thermistor
 

gstide

Premium Member
Joined
Aug 18, 2019
Messages
5
Location
wa

I took a short video. Hope it helps. thanks!
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
1,910
Location
Canada
gstide said:
So, when the tech sheet says "check resistance of the thermistor", I should check the pins on the wire, not those on the board, correct?
Yes.


gstide said:
The tech sheet also says "check thermistor for short to ground". How do i do that?
The body of the thermister looks to be metal so measuring from either (or each) of its wires to the body of the thermister (or maybe its mounting screw) on the highest ohm scale would test for a short to ground. There should be infinite resistance.

461967846741.jpg

gstide said:
what I did is I measure the resistance between the microwave shell and the pins. Both pins show infinite. So I guess they are not short to ground?
Assuming the part that the thermister is attached onto is also grounded, that should be an adequate measure of a ground short. I'm not exactly sure where the thermisters are mounted.


I took a short video. Hope it helps.
I can't view the video. My browser says 'unsupported format'.

Dan O.
 
Last edited:

gstide

Premium Member
Joined
Aug 18, 2019
Messages
5
Location
wa
Thank you Dan, I will redo the measurement when I get a chance.
here is the video link:
 
Last edited:

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
1,910
Location
Canada
I can watch the video now but haven't seen such an occurrence myself.
 
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