How to fix your snapping, popping, sparking microwave oven – replace waveguide easily


So there I was the day after Thanksgiving…  The previous evening we enjoyed a yummy dinner of turkey, mashed potatoes, and gravy.   Now we all know that Thanksgiving leftovers are the best.  I quickly grab some turkey meat, pour some gravy on them, and pop them in the microwave for a quick reheat.  Imagine my surprise when I suddenly hear a loud crackle sound, and then a boom coming from the microwave.  Looking over, I even see some flashes of light coming from within the oven.

Now, I have a Sharp R-520KS microwave, but it turns out the problem I was experiencing is pretty common to all microwave ovens.  Within the microwave oven there is a device call the waveguide.   This is a hole  inside of the microwave that focuses the microwaves into the oven.  And over this hole is a cover which is made from mica paper.

Over time, this cover will collect food and crud on it, and eventually it will start to arc, if it gets bad enough, you will experience the same fireworks inside your oven that I did.  It is recommended that you try to keep it clean, but eventually it will probably need to be replaced.  Official replacements are often not cheap, and if you have an older oven, may no longer be available.

Luckily it is fairly easy to buy a sheet of mica paper and cut it yourself to match your existing cover.  I bought mine from Amazon (click on link below), and carefully traced the existing cover onto the paper.  Use a sharp knife, or scissors to cut out the new pattern.  Simply pop your new cover into place, and your microwave will be ready for many more years of service.


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