It may be that the seal between the pipe of the range hood and the flue of the house is not done well. If it's not about decoration, there is something wrong with the range hood. The power was cut off. If this sound is gone, it may be from the core of the power transformer that supplies power to the control circuit of the range hood. When the power is turned off, if the fan is still rotating, its delay function is working. If the fan does not rotate, there is still noise. It is estimated that there is something wrong with the computer board or motor. It is likely that there will be something wrong with the computer motherboard. Ask their after-sales service staff to change a computer board for you. After all, these are all necessary during the warranty period.