If only the center weight is dropping it is likely attributed to one of the following factors: The chimes are turned OFF with the lever likely at the 3 position The clock is not chiming all of the time and you do not notice it (this would require servicing the clock to correct the functionality). If the left weight is not dropping, it is because the striking of the hour is not operating and would require servicing to correct. Clocks which have the added feature of AUTOMATIC NIGHTTIME SHUTOFF will normally experience the center weight dropping faster than the left and right weights and is normal when this feature is used.