Our GE Profile built in microwave/convection oven stopped heating on both modes. The unit still has power since the screen is functional, all the keypads function and the unit turns on (fan(s) run) when started but neither the microwave system or the convection system heat the oven contents. The unit is out of the wall with top off to test the fuse (good) and the small side panels have been taken off to test the door interlocks. Guidance, please. Thanks.