Hi,Welcome to Just Answer, My name is XXXXX XXXXX forward to helping you today. lets get started.
if this is running and the turntable is turning as normal its the magnetron, this is what heats the food. unfortunately this would need to be replaced be a tech, microwaves are very dangerous to work on and can store a lethal amount of voltage even when unplugged. please be safe and call for service, this is the high vlotage side of the microwave. hope this helps, thanks Bryan