my daewoo microwave sparks inside and does not work?

Likely answer is that you have burnt on food on the wave guide cover, the arcing is from the magnetron behind it. Never run a microwave empty, it will destroy its own magnetron, thats the thing that makes the microwaves. taking the wave guide cover off and cleaning with a damp cloth around the area may help. if the cover is burnt get a new one, do not re-use

patrick
June 2012