Running but not heating — the classic fault
light, turntable and fan all working, the timer counting — and food comes out as it went in.
the magnetron (wave generator) reaching end of life — the classic fault, the HV diode or capacitor, the internal HV-circuit fuse, or a door switch not completing the circuit.
the water-cup test — one minute at full power: if the water stays cold the heating circuit fault is confirmed. Never open the unit — separating magnetron vs diode vs capacitor is technician work after discharging.



