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CS-50 Portamento/Glissando problem

 

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
 

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Where are you??

Could be a tech nearby...

On 21 Sep 2018, at 10:15 pm, sneakyflute@... [yamahacs80] <yamahacs80@...> wrote:

?

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
 

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Hi.?

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


On Sep 21, 2018, at 5:15 AM, sneakyflute@... [yamahacs80] <yamahacs80@...> wrote:

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
 

Hi - right now I'm in Germantown, NY, but I'm on route to Nashville where the tour starts. Then Texas... maybe a tech in Austin, Dallas, or Houston could help? Know anyone?
 

Thanks so much David. I'm sure I can find a Frys - or do a mouser order with quick shipping or something. I'll get some 4016 ICs. Do you think it could also be the 4069 (IC 23) or one of those two 4558 op amps (IC 21 and 22)? It now seems to be on two voices (maybe both had the issue before and I didn't notice). Thanks!
 

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You could try SST Rentals in Nashville, they may even have a 50.?

Switched On in Austin could either sort it out or point you in the right direction.

On 22 Sep 2018, at 6:52 am, sneakyflute@... [yamahacs80] <yamahacs80@...> wrote:

?

Hi - right now I'm in Germantown, NY, but I'm on route to Nashville where the tour starts. Then Texas... maybe a tech in Austin, Dallas, or Houston could help? Know anyone?

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