Sounded like the automatic lid closing mechanism was falling apart on our MaxxAir Vent Fan in our RV bathroom and it was!
Music Ocean by Uncan
MaxxFan 4500KMaxxAir part# MA1020281K1AF Controller Sony AS300R Action Camera Panasonic DMC FZ1000 Digital Camera Panasonic DMWMS2 Stereo/ Shotgun Microphone