[HAM] x77 GT non-latching selector keys

[Videoproducer]

Hi all!  I'm new to this list, and new to Hammond for that matter.  I just acquired an x77 that has not been used in some time.  I have discovered a few problems, one of which being the B upper drawbar selector key and the A# upper drawbar selector keys won't latch.  Anyone have any suggestions on how to solve this one?  I have tried repeated depression of the keys.  They just don't seem to be touching the latching mechanism.

Thanx in advance
Will