Broke after two years, started sparking Sharp R 520J 1200 Watts Microwave Oven

(I posted this by accident on the LK model site. I suspect they are similar microwaves, however).
I filed a report with the Consumer Product Safety Commission on my Model 520JK microwave, and also contacted Sharp USA. These are cheap enough to throw away when they break, but I am concerned that someone might get hurt by one of these machines.
After two years of use at our summer home, the START and 6 buttons stopped working. After unplugging and letting it sit for a few minutes and plugging back in, it seemed to solve the problem - at least temporarily.
Tags: , Home and Garden, Microwave Ovens, Sharp R-520J 1200 Watts Microwave Oven