Archive of the former Yahoo!Groups mailing list: Yamaha CS80

Looking at the KAS schematic, I’d guess it’s likely IC 9 or 10 - 4016 quad switch. Since the CS50 only plays 4 notes, I think IC 11 and 12 are not installed.   I’d try removing IC9 and 10, putting in 14 pin DIP sockets and then putting them back swapped.  If one off them was the problem, then the broken voice should move to a different one of the 4 voices. These chips are still pretty common so you can buy them but the only physical stores with them would be old time electronic supply shops or Fry’s. Sometimes I miss Radio Shack!

Good luck,

 David

Hi. I'm on tour with my CS-50 and one voice suddenly is stuck on Glissando (I can't switch it to portamento). I need to fix it fast before the next show...

I only have a meter and soldering iron (and limited knowledge and skills :) with me, so I'm hoping to just quickly swap in some new parts (can't do much testing). 

Is the issue likely to be the comparator IC (the 4069 inverter) in that part of the circuit (IC23), or is there something else I should target? Again, glissando works - so maybe the gate is stuck on?? I would like to try to make one stop or one order for parts before I attempt to do this, so it would be great to hear some of your guesses so I can get those parts before I go in. 

Thanks! DT