The buzzing signal for the timer and preheat oven temperature goes on at the proper times as well as at random times when I am not using the oven. I have turned off the electricity at the circuit breaker and exposed the circuit panels. I dusted the panels as there was lint and soot. When I reconnect with electricity I hear a clicking sound, the convection fan goes on and the buzzer starts sounding. The sound continues until I turn of oven on and off.