Yamaha CS80

So, I just finished replacing almost all of the 4000 series logic IC's in my Yamaha CS-80.  I 
totally screwed it up.  I've got sustaining voices, unusual behavior and a couple of voices 
that only track the keyboard if you play a few notes at the same time.    

In retrospect, replacing most of the IC's might have been a bad idea.    One theory that I 
have is that the 4006 registry shifters that I couldn't replace are having problems keeping 
up with the propagation delay of the new IC's?   Furthermore, soldering a cap across the 
rails on the TKC board might have been a bad idea too.  Electrically, it doesn't make any 
sense to couple two rails together but a respectable website suggested it and other people 
said that it didn't cause any adverse affects?

Is there any systematic proceedure for restoring these things?   Initially, I was hesitant to 
turn any of the potentionometers - I figured that the thing would probably get back into 
calibration once I replaced the faulty IC's.  I was scared of stressing the potentionometers 
too. Maybe I should have calibrated it after I recaped and before I installed all of the new 
IC's.  Some of the calibration proceedures were off by significant values - another reason I 
figured that my problem was rooted within the IC's.

Here's a brief synopsis of the problems I'm facing:

1.) Before I replaced the IC's square wave output was distorted if more than one voice was 
sounding.  This was basically the main reason I replaced most of the IC's.  I still have this 
problem.  

2.) One voice, the last voice played, sustains indefinately in sustain I and II.

3.) Aftertouch doesn't work on the voice that is sustaining.

This thing is really sick and hard to isolate problems.  I don't have it in front of me either 
so it's harder to blog about it. 

Does anybody have any suggestions or referrals?

-Mike
312-363-7286