Microwave heats, but no light, turntable or fan

I have a GE Spacemaker microwave that heats fine. However, there are no interior or cooktop lights, no turntable and no fan. The vent fan is the only other item that works. The control panel works properly. There was a pop at the end of cooking cycle, followed by the above items no longer working. I now hear a buzz when starting the microwave as well. Am I looking at a faulty smart board?