Possible home fixes for a KitchenAid microwave oven include pressing and holding Start or Cancel, cleaning the turntable and removing the spacer. Do not attempt repairs on the inside of a machine, as this carries a risk of electric shock.
If a lock icon appears on the microwave's display, press and hold Start or Cancel for five seconds to deactivate the child lock feature. When the icon disappears and the tones sound, the microwave should return to normal function. If the turntable is not operating, take it along with its support out of the appliance, and wash them both with warm, soapy water. Test all rollers to ensure they work properly. If the microwave does not operate, check to see that the spacer is removed. The spacer does not allow the door to close properly, which inhibits the microwave's function.
To test the microwave's magnetron, heat one cup of water for two full minutes. If it does not get warm, the device may require a new magnetron. This repair cannot be completed by an amateur. Also check the exterior and interior of the microwave for visible damage; a damaged microwave should be unplugged immediately. If the microwave oven still does not work after performing these repairs and tests, call KichenAid customer support to schedule a visit from a qualified repair technician.