• ** 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 721.62643200 Kenmore Microwave / loud humming and burn electrical smell

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jasper

Premium Member
Joined
Jan 15, 2011
Messages
43
Location
Minnesota
Model Number
721.62643200
Brand
Sears Kenmore
Age
More than 10 years
Hello...

My Kenmore over the range microwave, installed in 2003, just started suddenly humming/buzzing VERY loudly when in use. There was also a burnt electrical smell coming from the microwave itself...seeming NOT from cooking cavity, but from the outside area. It was being used when this happened, so I cancelled the heat cycle, and reprogrammed it, and again it was humming/buzzing very loudly. At that point, I unplugged it.

We were looking at new models...but quite honestly, I like the one we have, so wondering what you think the problem is, and if it perhaps I can repair it. I'm pretty mechanically inclined, and always up for a challenge to keep this out of the waste steam if I can.

I'm thinking the magnetron has gone bad, but will welcome any other suggestions.

You guys have been so helpful to me in the past...helping me repair my Frigidaire gas range, and my Whirlpool refrigerator a couple times.....all with complete success.

Thanks,
Jasper
 
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Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
5,968
Location
Ontario, Canada
jasper said:
I'm thinking the magnetron has gone bad, but will welcome any other suggestions.

More often your complaint is the high voltage diode. When they blow they often totally disintegrate leaving little behind except the two wire ends. It usually attaches between the capacitor and a ground.

This is actually the Diode


*Be sure to discharge the capacitor before performing any investigation on the interior components.*


Dan O.
 

jasper

Premium Member
Joined
Jan 15, 2011
Messages
43
Location
Minnesota
Thanks Dan.....I'll check on that in the next few days. I'm guessing I won't be able to get in there without uninstalling the entire microwave....so it might be a few days.

I appreciate your reply....and will post my findings.

Jasper
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
5,968
Location
Ontario, Canada
jasper said:
I'm guessing I won't be able to get in there without uninstalling the entire microwave

I don't know how that model is designed. It is possible to service some components of some models by just removing the control panel but it is usually much easier to service if removed from its mounting.

JMO

Dan O.
 

jasper

Premium Member
Joined
Jan 15, 2011
Messages
43
Location
Minnesota
More often your complaint is the high voltage diode. When they blow they often totally disintegrate leaving little behind except the two wire ends. It usually attaches between the capacitor and a ground.

This is actually the Diode


*Be sure to discharge the capacitor before performing any investigation on the interior components.*


Dan O.
Dan O., You're a genius!!! I replaced the High Voltage Diode, exactly as you suggested, and my microwave is back to working flawlessly.

I will add for the benefit of others, my diode wasn't blown apart, didn't show any signs of wear....looked totally normal, but I used my multi-meter, which fortunately has a diode test mode, and it did test as faulty.

I really appreciate your knowledge and assistance, and will be adding to the site tip jar.

Jasper
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
5,968
Location
Ontario, Canada
Thanks for the followup.


Dan O.
 
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