I have seen the vibration caused by one of the motors. There is not an easy way to diagnose which one is the cause though. What you will find is that when the motor reaches a harmonic vibration the whole Phantom will begin to be vibrating. Put your Phantom in a hover about 6 feet off of the ground and a safe distance from you, after a few seconds of hovering you will see the camera assembly showing pretty bad vibrations. Give some throttle up, it goes away, but will return when back to hovering.