A microwave oven (commonly referred to as a microwave) is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce thermal energy in a process known as dielectric heating. Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer 25–38 mm (1–1.5 inches) of a homogeneous, high water content food item.
Microwave is not heating is a common problem. Most popular reason behind this issue is magnetron failure. A magnetron uses high voltage to produce microwave frequency to cook food. If the microwave is turned on when it is empty, this cause the magnetron to burn out. A burned magnetron has to be replaced as it cannot be repaired. Other probable causes behind this problem are faulty diodes, capacitor burn, defective door switch and transformer failure.
Possible causes behind this issue are faulty door switch, failed transformer, defective touch pad and faulty fan motor.
If the microwave buttons do not work it indicates that the touch-pad or the control panel are defective or have been damaged. Another possible reason can be defective main control board.
In a microwave there is a rotating motor below the plate which is responsible for the rotation of spinning plate. So the most probable cause behind this issue is a worn out or burned motor. Motor can be easily replaced. However, if the motor is not defective this indicates a fault in the main control board. If the control board is fine then check touch pad or control panel for the problem.