This camcorder is equipped with a Balanced Optical SteadyShot system which controls the entire optical path, including the lens and image sensor as one floating unit. When the power is turned off, however, the camcorder cannot control this floating unit. The clacking sound is made by the floating unit touching the surrounding cushioned material. This is not a malfunction and the camcorder has passed Sony's standard test methods for durability.
When the power is turned on, the floating unit may vibrate. This is the camcorder's operation to position the lens appropriately, and is not malfunction.