• ** 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

FIXED KCMS2055SSS1 Microwave Not Operating

wpollock

Premium Member
Joined
Dec 14, 2009
Messages
20
Location
California
Model Number
KCMS2055SSS1
Brand
KitchenAid
Age
6-10 years
Hope you and yours are enjoying a wonderful holiday season so far. I have a KCMS2055SSS1 microwave unit which is notorious for having door switches go bad. The unit has power but will not turn the turntable/run after entering a use time and hitting the start button. However, I can ever so slightly push in on the door opener and the unit will run.

Service companies have changed door switches on four different calls and when I ask them why the same issue recurs they say the switches are just a cheap and unreliable part.This unit is in a home I rent and I would like to consider replacing the switch(es) myself.

I am no professional repair person but have watched how the unit is removed from the cabinet and how the casing is removed. Is a special tool required to remove the screws holding the casing and/or switches or can I use a standard phillips head screwdriver? Also, does the unit store voltage in the capacitor after being unplugged that I need to dissipate before removing the switches? I do not recall seeing any service technician cross grounding anything for this purpose when they have replaced switches on this unit.

Any input is appreciated and thanks.
 

wpollock

Premium Member
Joined
Dec 14, 2009
Messages
20
Location
California
I ordered ERP switches and they have arrived. The switch configuration on my unit uses the Common (with black and pink wires) and Normally Open(with green,yellow and white and tan wires) switch terminals. If I understand Electricity 101 correctly, a Normally Open switch tests good when the switch is activated.

In my case this will be when the door is closed and the latch assembly has all three switch buttons depressed/closed. If this is correct can I test each switch by attaching gator clips connected to my multimeter to the Common and Normally Open switch terminals without removing any of the wiring terminal clips coming from the microwave?

Pictures are attached showing the bottom and middle switches in one and the top switch in another. I will have to remove the terminal clip from the top switch because it is a single piece unit that completely covers the switch terminals.

Microwave Bottom and Middle Door Switches.jpg Microwave Top Door Switch.jpg
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
101,466
Location
McMullen Valley, Arizona
Hi,

Rick is our microwave guru, I'll see if Rick can assist you.:)

Jake
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,386
Location
Murray, Utah 84107, United States
A few basic rules you alway follow are when checking resistance or continuity always unplug the machine and when checking for continuity or resistance always remove at least one wire from the component you're checking. A microswitch can be 2 switches (a NO switch and a NC switch) so always remove the wire from the Common terminal.
R-Microswitches.jpg

Check the microwave door switches by opening and closing the door. Sometimes the problem isn't the switch but the switch holder or bracket. Make sure the screws are tight. Some have a small amount of adjustment. No special tools required other than a Phillips, Torex, or ¼" hex head. You don't need to discharge the capacitor. Most of them have a bleed resistor connected. Static electricity has more voltage.

Here's a trick I use for testing microwaves with hard to reach places to get a measurement:
safety pin trick.jpg
 

wpollock

Premium Member
Joined
Dec 14, 2009
Messages
20
Location
California
Thanks for the information Rick.

Just so I am sure about testing the switches to determine if they are good or not, a NC switch,either a two terminal or a three terminal with connections to the common and NC terminal, should test good for continuity before the switch is activated(that is the small pin or button on top is depressed?

If correct, a two or three terminal connected NO switch should test good after the switch is activated.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,386
Location
Murray, Utah 84107, United States
Switch terminals- COM (Common) NO (Normally Open) NC (Normally Closed).

The Normal condition of the switch is just like in the picture, the switch button is not depressed. When the door is open the switch is in its normal state so C-NC will read closed on your meter and C-NO will read open. With the door closed, just the opposite.
 

wpollock

Premium Member
Joined
Dec 14, 2009
Messages
20
Location
California
Is there anyone active right now on the forum and who can provide the correct way to reinstall the middle door switch shown in the attached picture without breaking the door latch assembly?It doesn't appear to have a tab like the bottom switch that is pushed to allow the switch to pivot out of and into operating position

Thanks
 

wpollock

Premium Member
Joined
Dec 14, 2009
Messages
20
Location
California
Sorry for the picture without any text. Here are a couple of more pictures showing the door latch assembly with the middle switch completely removed and one with the switch partially installed. The more I move the switch down(towards its operational position)there is more resistance which I assume is due to the switch contacting the door latch assembly(particularly the round white piece) on its back side.

Microwave Bottom and Middle Door Switches1.jpg Microwave Bottom and Middle Door Switches2.jpg
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,386
Location
Murray, Utah 84107, United States
To remove the primary or monitor interlock switch: Place the blade of a flat-blade screwdriver between the switch body and the holder. Twist the blade until the switch is free of the tabs, and remove the switch from the holder.
 

wpollock

Premium Member
Joined
Dec 14, 2009
Messages
20
Location
California
Got the switches reinstalled,the outer casing in place and the unit plugged in.As for now it is operating as it should. No doubt another switch will eventually go bad based on its history. I would ask rickgburton to consider making a video tutorial for removing/installing all switches on this model unit should he find himself doing so.
Thanks for all the invaluable help.
 

wpollock

Premium Member
Joined
Dec 14, 2009
Messages
20
Location
California
Reinstalled removed switches and outer casing. Powered up unit and it is currently operating as it should. I would ask rickgburton to consider making a short video tutorial showing how he removes and installs door switches for this model microwave should he do so in the future

Thanks for all the help
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,386
Location
Murray, Utah 84107, United States
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