To avoid personal injury or death, disconnect your appliance from its power source
before you start any troubleshooting or repair work. Use caution when working inside any appliance.
If you see anything sparking inside your microwave, turn it off right away.
There are a few reasons for sparks inside the microwave. One is that food
or liquid got spilled and was not cleaned up properly. Anytime there
is a food or liquid spill inside the microwave oven, it should be cleaned
up as soon as possible. When cleaning the unit, turn off the appliance
immediately, and unplug it. Another reason for sparks may be that there
is metal in the cooking area. Do not use any metal dishes or utensils
in your microwave. There may also be problems with an internal part
that's defective causing an arc or spark. If you see burn spots inside
your microwave, don’t use it until you have it examined by a professional
appliance repair person.