Hi there. I am having the exact same issue that was shown in the video with my Samsung microwave. Microwave operates as normal when in use (light and fan comes on, turntable turns, food heats up) but there is a humming noise that continues after the cooking time has expired or when the unit is not being used but the door is closed. Open the door, the humming stops. My model number is SMK9175ST. Any suggestions on first steps to take to figure out the problem?