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Vintage Synth Repair

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Yamaha CS 5 almost works, but the keyboard...

Yamaha CS 5 almost works, but the keyboard...

2011-11-26 by ahassine@nettilinja.fi

Hi All!!!

I just got the Yamaha CS 5 back from the repair and now it works fine...almost :)  It took the changing of one IC and several smaller bits with the guidance of the japanese service manual. Luckily some of it was in english, ie. schematics...

The unit works now fine, all the pots work as they should. But when I touch any of the keys, sound dissappears immediately. It is not up to any of the EG depth/VCA pots, because when I turn the Initial Volume pot up I get a continous note and all the pots modify the sound just the way they should. But press a key and the sound goes quiet. And then I have to switch the synth off and back to make it make sound again. 

I am able to control the synth via the keyboard of the CS-15 by using the gate/CV inputs in the CS 5. So I can use it as an expander for my CS-15, but certainly would like to make its kbd work as well...

Any ideas where to look for the problem???  

thanks and cheers!

Ami H

Re: [vintagesynthrepair] Yamaha CS 5 almost works, but the keyboard...

2011-11-26 by klosmon

First thing to check is what's happening at the output jacks -- is there key voltage and trigger at the rear panel jacks?

~G

ahassine@... wrote:
Show quoted textHide quoted text

Hi All!!!

I just got the Yamaha CS 5 back from the repair and now it works fine...almost :) It took the changing of one IC and several smaller bits with the guidance of the japanese service manual. Luckily some of it was in english, ie. schematics...

The unit works now fine, all the pots work as they should. But when I touch any of the keys, sound dissappears immediately. It is not up to any of the EG depth/VCA pots, because when I turn the Initial Volume pot up I get a continous note and all the pots modify the sound just the way they should. But press a key and the sound goes quiet. And then I have to switch the synth off and back to make it make sound again.

I am able to control the synth via the keyboard of the CS-15 by using the gate/CV inputs in the CS 5. So I can use it as an expander for my CS-15, but certainly would like to make its kbd work as well...

Any ideas where to look for the problem???

thanks and cheers!

Ami H


Re: Yamaha CS 5 almost works, but the keyboard...

2011-11-26 by ahassine@nettilinja.fi

Hi!!!

Thanks for the reply...I tried the vice versa and connected the CS 5 to control CS-15 and it´s the same problem. Pressing a key on CS 5 (master) kills the sound of CS-15 (slave). 

Moreover, I noted that the pulse wave doesn´t work, only the saw is producing a sound on the CS 5. But I could live with that if the keyboard only worked...  The repair guy said that he could see with his meters that the keyboard is actually producing changes in the voltage, but it seemed to stop at the large IC on the card. Unfortunately it´s Yamahas own chip, so probably very hard to get nowadays...

cheers,
Ami



--- In vintagesynthrepair@yahoogroups.com, klosmon <klosmon@...> wrote:
Show quoted textHide quoted text
>
> First thing to check is what's happening at the output jacks -- is there 
> key voltage and trigger at the rear panel jacks?
> 
> ~G
> 
> ahassine@... wrote:
> >  
> >
> > Hi All!!!
> >
> > I just got the Yamaha CS 5 back from the repair and now it works 
> > fine...almost :) It took the changing of one IC and several smaller 
> > bits with the guidance of the japanese service manual. Luckily some of 
> > it was in english, ie. schematics...
> >
> > The unit works now fine, all the pots work as they should. But when I 
> > touch any of the keys, sound dissappears immediately. It is not up to 
> > any of the EG depth/VCA pots, because when I turn the Initial Volume 
> > pot up I get a continous note and all the pots modify the sound just 
> > the way they should. But press a key and the sound goes quiet. And 
> > then I have to switch the synth off and back to make it make sound again.
> >
> > I am able to control the synth via the keyboard of the CS-15 by using 
> > the gate/CV inputs in the CS 5. So I can use it as an expander for my 
> > CS-15, but certainly would like to make its kbd work as well...
> >
> > Any ideas where to look for the problem???
> >
> > thanks and cheers!
> >
> > Ami H
> >
> >
>

RE: [vintagesynthrepair] Re: Yamaha CS 5 almost works, but the keyboard...

2011-11-26 by Lorne Hammond

Is it possible yopu have a cable on backwards? And, have you gently reheated the connectors solder?

From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of ahassine@nettilinja.fi
Sent: Saturday, November 26, 2011 9:30 AM
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: Yamaha CS 5 almost works, but the keyboard...

Hi!!!

Thanks for the reply...I tried the vice versa and connected the CS 5 to control CS-15 and it´s the same problem. Pressing a key on CS 5 (master) kills the sound of CS-15 (slave).

Moreover, I noted that the pulse wave doesn´t work, only the saw is producing a sound on the CS 5. But I could live with that if the keyboard only worked... The repair guy said that he could see with his meters that the keyboard is actually producing changes in the voltage, but it seemed to stop at the large IC on the card. Unfortunately it´s Yamahas own chip, so probably very hard to get nowadays...

cheers,
Ami

--- In vintagesynthrepair@yahoogroups.com, klosmon <klosmon@...> wrote:
>
> First thing to check is what's happening at the output jacks -- is there
> key voltage and trigger at the rear panel jacks?
>
> ~G
>
> ahassine@... wrote:
> >
> >
> > Hi All!!!
> >
> > I just got the Yamaha CS 5 back from the repair and now it works
> > fine...almost :) It took the changing of one IC and several smaller
> > bits with the guidance of the japanese service manual. Luckily some of
> > it was in english, ie. schematics...
> >
> > The unit works now fine, all the pots work as they should. But when I
> > touch any of the keys, sound dissappears immediately. It is not up to
> > any of the EG depth/VCA pots, because when I turn the Initial Volume
> > pot up I get a continous note and all the pots modify the sound just
> > the way they should. But press a key and the sound goes quiet. And
> > then I have to switch the synth off and back to make it make sound again.
> >
> > I am able to control the synth via the keyboard of the CS-15 by using
> > the gate/CV inputs in the CS 5. So I can use it as an expander for my
> > CS-15, but certainly would like to make its kbd work as well...
> >
> > Any ideas where to look for the problem???
> >
> > thanks and cheers!
> >
> > Ami H
> >
> >
>

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