trouble removing the plate

[ed miller]

Has anyone out there ever had trouble removing a plate from a vertical piano 
(or a grand for that matter).

I am stumped. I cannot get the plate out of the Knabe 50" Upright I am 
working on. I am certain that all of the screws and other assorted hardware 
have been removed. The bottom of the plate is free, but the top around over 
the pinblock will not budge. When I lift it the whole piano comes with it.

Is it possible there is a hidden screw I have not thought of?
Is it possible the plate was glued or epoxied to the pinblock?

Can anyone help me?

Thank you,
Ed