Yamaha CS80

I am looking for an expansion spring for the ribbon assembly, a potentionometer for VCO 
bank II detune, and possably an aftertouch pad (Not sure if these things go bad or not?).

Futrthermore, I am having trouble with oscillator bank II and the square wave function.  When 
I flip the square wave switch in bank II and engage more than one note, I get a nasty 
distorted sound. 

 I just recaped the entire thing and don't think that I made any mistakes or damaged anyting.  
I haven't replaced any 4000 series logic chips because I am scared that the new ones will not 
behave the same as the old ones.  

Are my concerns regarding the logic chips meritable?  Is TI an ok brand to use?  What sould I 
do about propigation delay and the different internal resistances when replacing the old with 
the new?

Are there any other pitfalls to avoid?

-Mike Borish
312-363-7286