• ** 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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Kenmore Elite 721.79203010 frequent interlock switch replacements

ccupples

Premium Member
Joined
Jan 19, 2010
Messages
19
Location
Texas
Model Number
721.79203010
Brand
Sears Kenmore
Age
6-10 years
My 8½ year old Kenmore Elite 7920 microwave has been consuming interlock switches at an increasing rate since the first failure a little over four years ago. I'm now facing my fourth (I think) replacement. I've got another switch (two, actually, one for the current repair and another to have on hand for the next inevitable replacement) on order, but I thought this would be an opportune time to inquire whether there might be some underlying cause for the frequent switch failures. I recall the last time I replaced the switch it looked a bit scorched and the connector attached to the wires was a bit deformed/melted. (I'll post pics when I open the cabinet up to replace the switch once it arrives.)

Thoughts from the experts?
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
107,919
Location
McMullen Valley, Arizona
Hi,

I'll see if Rick can assist you on this Microwave.

Jake
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
2,599
Location
Canada
ccupples said:
The interlock switch connectors don't look as bad as those going to the thermostat.

Both those components need new wire connectors installed. If trimming back the wires to an unaffected portion makes the wiring too short, that whole wire might have to be replaced.

ccupples said:
I recall the last time I replaced the switch it looked a bit scorched and the connector attached to the wires was a bit deformed/melted.

The terminal(s) should have been corrected then. Installing a bad connector onto the terminal of a good component will usually shorten that component's lifespan, often considerably.



JMO

Dan O.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
37,663
Location
Murray, Utah 84107, United States
It's those stupid plastic wire ends that's causing the problem. I agree with Dan. Cut them off and get a few Hi-Temp solderless spade connectors. Cut the wire back until the wire strands shiney and not dull. I noticed something else in your picture that may or may not be a problem. I can't tell if I'm looking at an optical illusion . Are these heat sink fins on the mag tube bent out of place?
Snapshot_1.jpg
 
Last edited:

ccupples

Premium Member
Joined
Jan 19, 2010
Messages
19
Location
Texas
I appreciate the input, guys. I will follow your advice and replace the connectors.

Thanks also for the observation on the heat sink fins. I don't think that's an optical illusion, but I have no idea how they got bent out of shape. Should it just be a simple matter of pushing them back into proper position to fix?
 
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