Loud snap at Start in Kitchenaid

our KitchenAid microwave makes a very loud Snap! when it starts, but only when the room humidity is over 70% from weather or from boiling on stove underneath. Is it dangerous? Can it be fixed? Why does it make this loud snap?

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right when it turns on it pops? that sounds like it could be a grounding issue in the microwave. i would honestly advise against using it if you hear electricity popping like that when you power it on. im not very savvy on repairing household appliances but i DEFINITELY wouldn’t use it anymore until properly repaired.

if youre feeling adventurous you could

unplug it and let it sit for a while for the residual electricity to dissipate, then open it up carefully and see if you notice any scorch marks on any of hte PCBs or wires in the unit itself.


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Yes, right when it turns on, just once. Never smell any burning. Thank you for your ideas here!




What is the model number of the microwave oven.

A loud electric type sound on starting in humid conditions may be an indication of sparking occurring between components or components and the cover of the microwave oven when there shouldn’t be.

The microwave oven sitting above the stove will get all the steam (particles in the steam) etc passing though it and this may leave a coating on the components. In humid conditions, current can flow because moisture in the accumulated coating conducts electricity, especially the high voltages used in the magnetron circuit i.e. HV diode, HV capacitor, HV transformer etc.

The oven would need to be opened and the components checked to see if they are clean from any coating caused by the steam etc. Look for any obvious signs of sparking e.g. burn marks on the inside of the cover or on the board.

Be safety aware when working in microwave ovens. The HV capacitor can store >5000V DC for months even if the power has been disconnected of this length of time. This amount of voltage can seriously injure you. The HV capacitor needs to be discharged correctly as soon as it can be accessed after removing the microwave cover, before commencing any other work inside the cabinet. If you don’t know what you’re doing then don’t do it! Call a reputable, professional appliance repair service and ask for a quote.


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Model: KMHS120ESS - 8. I never smell any burning or anything. Thank you for your ideas!


@Tom Riordan

I would still open it up and check it out.

You only have to look at the filters in a range hood above cooktops to see how greasy they can get and moisture conducts electricity. This will also be happening to your microwave.

Here's a parts diagram that may help with disassembly.




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