Yamaha CS80

Dear CS-80 friends,

i am currently restoring a CS-80 which collected dust for some 10+ 
years in a warehouse. Fortunately everything seems to work so far, but 
of course the tuning is a bit off.

When starting the tuning procedure i cannot go beyond step 2. According 
to the manual Value at pin 13 of IC2 KAS board should be set to 125mV. 
Mine stays always at 135mV- no matter how i turn the corresponding VR1 
pot. VR1 pot itself is ok though.

Anybody has a hint?

Thanks, Gregor

ive never tuned one via DVM. why dont you tune it via the audio output? does VR1 affect output pitch? sure you've got the right voice? sorry if im oversimplifying something about your situation....

oh, and as cs-80 nerds, im sure we all would be intrigued by the instruments back-(and fore-) story.


--- On Sat, 8/9/08, willgregori <will.gregory@...> wrote:

From: willgregori <will.gregory@...>
Subject: [yamahacs80] Expert question- Tuning procedure - stuck at step 2
To: yamahacs80@yahoogroups.com
Date: Saturday, August 9, 2008, 12:49 PM










    
            Dear CS-80 friends,



i am currently restoring a CS-80 which collected dust for some 10+ 

years in a warehouse. Fortunately everything seems to work so far, but 

of course the tuning is a bit off.



When starting the tuning procedure i cannot go beyond step 2. According 

to the manual Value at pin 13 of IC2 KAS board should be set to 125mV. 

Mine stays always at 135mV- no matter how i turn the corresponding VR1 

pot. VR1 pot itself is ok though.



Anybody has a hint?



Thanks, Gregor




      

    
    
	
	 
	
	








	


	
	


      

[Non-text portions of this message have been removed]

VR1 has something to do with the global tuning i guess, i just wonder 
why it does not affect the Volatge on pin13 IC2- as it is described 
in the tuning manual. 

Since i am an absolute beginner in tuning a cs-80 i just follow the 
instructions, i have no clue what is important and what can be 
skipped.

Actually my particular CS-80 is from switzerland, it belonged to a 
collector who had an enormous collection of vintage synths (bought 
also 3 racks of system 100m there)in a dusty warehouse. Shame on me, 
this was in 2001 already and I did not find the time to take much 
care of this CS-80 yet...I have just too much other synths which 
needed service and the cs-80 seems to be a true masterpiece in terms 
of maintenance...



--- In yamahacs80@yahoogroups.com, rj krohn <r_j_d_2.phila@...> wrote:
>
> ive never tuned one via DVM. why dont you tune it via the audio 
output? does VR1 affect output pitch? sure you've got the right 
voice? sorry if im oversimplifying something about your situation....
> 
> oh, and as cs-80 nerds, im sure we all would be intrigued by the 
instruments back-(and fore-) story.
> 
> 
> --- On Sat, 8/9/08, willgregori <will.gregory@...> wrote:
> From: willgregori <will.gregory@...>
> Subject: [yamahacs80] Expert question- Tuning procedure - stuck at 
step 2
> To: yamahacs80@yahoogroups.com
> Date: Saturday, August 9, 2008, 12:49 PM
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>     
>             Dear CS-80 friends,
> 
> 
> 
> i am currently restoring a CS-80 which collected dust for some 10+ 
> 
> years in a warehouse. Fortunately everything seems to work so far, 
but 
> 
> of course the tuning is a bit off.
> 
> 
> 
> When starting the tuning procedure i cannot go beyond step 2. 
According 
> 
> to the manual Value at pin 13 of IC2 KAS board should be set to 
125mV. 
> 
> Mine stays always at 135mV- no matter how i turn the corresponding 
VR1 

> 
> pot. VR1 pot itself is ok though.
> 
> 
> 
> Anybody has a hint?
> 
> 
> 
> Thanks, Gregor
> 
> 
> 
> 
>       
> 
>     
>     
> 	
> 	 
> 	
> 	
> 
> 
> 
> 
> 
> 
> 
> 
> 	
> 
> 
> 	
> 	
> 
> 
>       
> 
> [Non-text portions of this message have been removed]
>

i would bail on voltage measuring in regards to tuning. just follow the procedure for tuning in regards to trim pots and scaling(says the idiot who just tried to help a fellow 80 owner with their tuning and forgot that you MUST do 2' first. was that my 4th or 5th time forgetting this crucial step?).

--- On Mon, 8/11/08, willgregori <will.gregory@...> wrote:

From: willgregori <will.gregory@...>
Subject: [yamahacs80] Re: Expert question- Tuning procedure - stuck at step 2
To: yamahacs80@yahoogroups.com
Date: Monday, August 11, 2008, 4:54 PM










    
            VR1 has something to do with the global tuning i guess, i just wonder 

why it does not affect the Volatge on pin13 IC2- as it is described 

in the tuning manual. 



Since i am an absolute beginner in tuning a cs-80 i just follow the 

instructions, i have no clue what is important and what can be 

skipped.



Actually my particular CS-80 is from switzerland, it belonged to a 

collector who had an enormous collection of vintage synths (bought 

also 3 racks of system 100m there)in a dusty warehouse. Shame on me, 

this was in 2001 already and I did not find the time to take much 

care of this CS-80 yet...I have just too much other synths which 

needed service and the cs-80 seems to be a true masterpiece in terms 

of maintenance. ..



--- In yamahacs80@yahoogro ups.com, rj krohn <r_j_d_2.phila@ ...> wrote:

>

> ive never tuned one via DVM. why dont you tune it via the audio 

output? does VR1 affect output pitch? sure you've got the right 

voice? sorry if im oversimplifying something about your situation... .

> 

> oh, and as cs-80 nerds, im sure we all would be intrigued by the 

instruments back-(and fore-) story.

> 

> 

> --- On Sat, 8/9/08, willgregori <will.gregory@ ...> wrote:

> From: willgregori <will.gregory@ ...>

> Subject: [yamahacs80] Expert question- Tuning procedure - stuck at 

step 2

> To: yamahacs80@yahoogro ups.com

> Date: Saturday, August 9, 2008, 12:49 PM

> 

> 

> 

> 

> 

> 

> 

> 

> 

> 

>     

>             Dear CS-80 friends,

> 

> 

> 

> i am currently restoring a CS-80 which collected dust for some 10+ 

> 

> years in a warehouse. Fortunately everything seems to work so far, 

but 

> 

> of course the tuning is a bit off.

> 

> 

> 

> When starting the tuning procedure i cannot go beyond step 2. 

According 

> 

> to the manual Value at pin 13 of IC2 KAS board should be set to 

125mV. 

> 

> Mine stays always at 135mV- no matter how i turn the corresponding 

VR1 

> 

> pot. VR1 pot itself is ok though.

> 

> 

> 

> Anybody has a hint?

> 

> 

> 

> Thanks, Gregor

> 

> 

> 

> 

>       

> 

>     

>     

> 	

> 	 

> 	

> 	

> 

> 

> 

> 

> 

> 

> 

> 

> 	

> 

> 

> 	

> 	

> 

> 

>       

> 

> [Non-text portions of this message have been removed]

>




      

    
    
	
	 
	
	








	


	
	


      

[Non-text portions of this message have been removed]

Hi,

In my book that would be step 4.

Before you do anything make sure the tune pot is centered trim the 
power supply, then check the TU pin on the KAS for 4.00 volts.

Then pin 6 of the lm310 for 0.125 volts holding down bottom C.

You need to check pin 38 as well as pin 13 on the YM2700 as one will 
effect the other.

If you still get no luck let me know.

Kent









--- In yamahacs80@yahoogroups.com, "willgregori" <will.gregory@...> 
wrote:
>
> VR1 has something to do with the global tuning i guess, i just 
wonder 
> why it does not affect the Volatge on pin13 IC2- as it is 
described 
> in the tuning manual. 
> 
> Since i am an absolute beginner in tuning a cs-80 i just follow 
the 
> instructions, i have no clue what is important and what can be 
> skipped.
> 
> Actually my particular CS-80 is from switzerland, it belonged to a 
> collector who had an enormous collection of vintage synths (bought 
> also 3 racks of system 100m there)in a dusty warehouse. Shame on 
me, 
> this was in 2001 already and I did not find the time to take much 
> care of this CS-80 yet...I have just too much other synths which 
> needed service and the cs-80 seems to be a true masterpiece in 
terms 
> of maintenance...
> 
> 
> 
> --- In yamahacs80@yahoogroups.com, rj krohn <r_j_d_2.phila@> wrote:
> >
> > ive never tuned one via DVM. why dont you tune it via the audio 
> output? does VR1 affect output pitch? sure you've got the right 
> voice? sorry if im oversimplifying something about your 
situation....
> > 
> > oh, and as cs-80 nerds, im sure we all would be intrigued by the 
> instruments back-(and fore-) story.
> > 
> > 
> > --- On Sat, 8/9/08, willgregori <will.gregory@> wrote:
> > From: willgregori <will.gregory@>
> > Subject: [yamahacs80] Expert question- Tuning procedure - stuck 
at 
> step 2
> > To: yamahacs80@yahoogroups.com
> > Date: Saturday, August 9, 2008, 12:49 PM
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> >     
> >             Dear CS-80 friends,
> > 
> > 
> > 
> > i am currently restoring a CS-80 which collected dust for some 
10+ 
> > 
> > years in a warehouse. Fortunately everything seems to work so 
far, 
> but 
> > 
> > of course the tuning is a bit off.
> > 
> > 
> > 
> > When starting the tuning procedure i cannot go beyond step 2. 
> According 
> > 
> > to the manual Value at pin 13 of IC2 KAS board should be set to 
> 125mV. 
> > 
> > Mine stays always at 135mV- no matter how i turn the 
corresponding 

> VR1 
> > 
> > pot. VR1 pot itself is ok though.
> > 
> > 
> > 
> > Anybody has a hint?
> > 
> > 
> > 
> > Thanks, Gregor
> > 
> > 
> > 
> > 
> >       
> > 
> >     
> >     
> > 	
> > 	 
> > 	
> > 	
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 	
> > 
> > 
> > 	
> > 	
> > 
> > 
> >       
> > 
> > [Non-text portions of this message have been removed]
> >
>

I've had some bad luck too in getting the exact voltages. After 
replacing all dual opamps, things got a bit better but still not 
100% according to spec. On my CS80 I didn't get some of the voltages 
(pin13 ic2; pin6 ic3, pin38 ic2) to spec even when I checked the 
power supply and had the TU at exactly 4.000V. However, ignoring 
this and after performing all the following steps (S/H + M-boards)I 
had my CS80 perfectly in tune on all ranges. I didn't realise pin 13 
and 38 interact with eachother, maybe I should try again and see if 
I can get everything according to spec then. Still I guess it will 
not help. Especially pin 6 ic3 was way off spec. Maybe some aged 
components are causing this ?

--- In yamahacs80@yahoogroups.com, "kent_spong" <kent_spong@...> 
wrote:
>
> Hi,
> 
> In my book that would be step 4.
> 
> Before you do anything make sure the tune pot is centered trim the 
> power supply, then check the TU pin on the KAS for 4.00 volts.
> 
> Then pin 6 of the lm310 for 0.125 volts holding down bottom C.
> 
> You need to check pin 38 as well as pin 13 on the YM2700 as one 
will 

> effect the other.
> 
> If you still get no luck let me know.
> 
> Kent
> 
>