grandfather clock?

My clock has been working fine for quite some time, but just recently, after winding the weights, the weight on the left ( as you face the clock ) does not drop. The center weight is dropping and the correct time is being shown. The weight on the right ( as you face the clock ) is dropping as well. Just the weight on the left is staying up at the top. Any ideas?
It is manufactured by Viking Clock Co, Fairhope Al. in 1987. The weights are raised with a crank handle inserted into the front face, at three locations. It has a moon dial and I think the movement is made by Steinway

Joe F.
September 2009