Crumar Performer PLEASE HELP!

[BonoVox9 at aol.com]

Can anyone here tell me what the four circuit boards are for that are 
underneath the keyboard in the perfomer? I am in the middle of trying to get 
mine to work, and I unplugged these four boards from the board they are 
mounted to and I turned it back on and the thing still plays notes. three of 
them look the same, and one is  biggger. What do these do? I don't 
understand. If they are unplugged, shouldn't it not work? With them in, there 
isn't any difference either. I don't understand if this thing is really 
messed up, or are these boards in there for nothing. I know they cannot be in 
there for nothing. 

If anyone knows anything about these, I would really appreciate some 
suggestions. I have tried to get help from other places, but, nobody 
responds.  I know the performer is a joke in the synth world, but, i happen 
to love the sound of it with my pro-one and fatman.

sincerely,
jason