Kimball Grand Dampers

[Terry Neely]

Hello to all. I hope someone can come up with something.
Critter:  Kimball grand approx 6' approx 11 years old. Spent its first
several years in a home on the coast of North Carolina. Generaly good
condition, some rust on strings. Moved to center of state recently, put
in room above a floor AC vent, resulting in a soundboard crack appearing
like a pistol shot in the middle of the night a week ago.
Problem: About 1/2 bass dampers do not damp properly. Will stop sound
after about 5 seconds.The rest of the bass ok Midrange and treble
dampers ok. A slight pressure on the damper head will result in proper
damping.(makes it hard to stay in tempo while playing, though) Notice
that dampers seem to stand a little proud above the strings while at
rest on the offending unisons
Solutions tried: Protek lifter wires to eliminate
sluggishness-successful. Needle dampers to soften felt- no help.
De-regulate dampers to the point that they are not lifting at all, just
hanging on strings while still attached to lifter lever- no help. Made
sure the lifters were not hanging up on the key end felt- no help

Could this be a problem with a lack of weight (or more properly
mass-right Del?)
Other thoughts?                 Thanks in advance,   Terry Neely