Comination Microwave

Question

Make PanasonicModel NN-A752WProblemOven and grill work fine. Since last week microwave function does not work.I have tried different power settings. All appears fine, lights, turntable and clock timer. The trouble is that there is no heat imparted to the food at the end of the cooking time. I have found and checked 2 internal fuses - they are ok.