Yamaha CS80

Hi Stephen,

I did it like this with quite satisfying results:

- take out OE board
- dial up a plain single sine wave voice (just one voice!)and keep it 
pressed at B4.
- turn VR3, VR4, VR5 and VR6 to "zero", I do not remember if it was 
clockwise or counterclockwise, have a try. These pots seem to control 
the amount of each delay line of the chorus effect
- listen to output via headphone and switch on chorus effect
- now turn VR3 slowly up, you will notice some increasing chorus 
effect on left or right side. Turn up until the effect is strongly 
audible
- now adjust VR7 pot and listen what happens. Depending on the 
positio of VR7, noises and artifacts can be heard. Adjust the pot 
until noise and artefacts are at a minimum level.
- Adjust VR3 again and find a level where chorus effect sounds just 
right (not too much but not to low)

Repeat procedure with VR4 and VR8, VR5 and VR9, VR6 and VR10 in pairs.

Hope that helps, good luck,

Gregor


--- In yamahacs80@yahoogroups.com, "Wavecomputer360" 
<wavecomputer360@...> wrote:
>
> Hi Will,
> 
> congratulations! I should adjust the Chorus/Tremolo section of 
mine, too. Any advice how to do it? Any caveats? I wouldn´t want to 
haul my CS around just for that minor bit of surgery...
> 
> Stephen
> 
> ____________________________________________________________________
> 
> "Ambition makes you look pretty ugly, kicking squealing Gucci 
little piggy." (Thom Yorke/Radiohead -- "Paranoid Android") 
> 
> Stephen Parsick live in concert: Bochum Planetarium (Germany), 13th 
of December, 2008, 08:00 pm.
> 
> Finally available: Stephen Parsick -- Traces of the Past Redux, 
reissued with three previously unreleased bonus tracks. For more info 
please check www.parsick.com
> 
> For legal downloads please check:
> 
> http://www.musiczeit.com/directory.php?
artist=296&title=Stephen+Parsick
> 
> 
>   ----- Original Message ----- 
>   From: willgregori 
>   To: yamahacs80@yahoogroups.com 
>   Sent: Saturday, January 24, 2009 5:12 PM
>   Subject: [yamahacs80] CS80 1271 back on duty...
> 
> 
>   Dear CS-80 friends,
> 
>   just want to report that my CS-80 no. 1271 has been successfully 
>   resurrected. I bought it 8 years ago from a guy in switzerland 
who had 
>   it sitting around probably more than 20 years without any service 
in 
>   his garage. Shame on me, I found no time earlier to take care of 
this 
>   baby, but now it plays like new again!
> 
>   Needless to say, I am pretty impressed by the quality and depth 
of its 
>   sound when fully calibrated to factory specs.
> 
>   Since this was my first CS80 to take care of, let me share my 
>   experiences when going through the complete tuning procedure:
> 
>   1) Some Keys had no velocity: First I suspected some damaged 4000 
chips 
>   and started swapping these on the TSB boards- until i noticed 
that the 
>   reason was actually some bend metal contacts on the Key sensors, 
grrr! 
>   Re-aligning the contacts helped immediately. 
> 
>   2)Following the tuning procedure I stucked quite early because 
the 
>   voltages on the KAS board seemed way off what should be right and 
could 
>   not be adjusted with the VR trimmers to factory spec. It took me 
quite 
>   some time to realize that I was using the wrong ground for this 
>   measurement, I took electrical ground straight from the PSU- but 
when 
>   taking the ground directly from KAS board it read out the proper 
>   Voltages perfectly. So from then, I always pick up ground from 
the card 
>   I am working on, not the PSU ground.
> 
>   3) Pitchbend did not work: Changed CA3140 on BA board
> 
>   4) Reference tuning Voltage on KAS board dropped from 4 Volts to 
0 
>   Volts suddenly: Broken TR29 on BA board.
> 
>   5) Reference tuning voltage on KAS board suddenly went to 8 
Volts: 
>   Broken 4069 clock
> 
>   6) enevelopes sounds different for VCA and VCF on each Voice, and 
some 
>   Voices had no attack at all. First I suspected some broken ENV 
chip 
>   here. The complete alignement of the envelopes is a quite 
elaborate 
>   procedure. I had to buy a digital oscilloscope for it and go thru 
the 
>   procedure several times, but finally everything could be adjusted 
>   without the need of exchanging ENV chips.
> 
>   7) Output level of Voice cards was different for each voice. 
Adjusting 
>   the levels to factory specs (VCA gain should be 80mV) resulted in 
a 
>   very low general output level, so I suspect this value is wrong. 
I just 
>   increased the level up to 200-300mV, just before it starts 
clipping the 
>   chorus and ensemble section. Now the output is much hotter and SN 
ratio 
>   of Effect section much better.
> 
>   8) Effect section: The adjustment procedure for the chorus and 
ensemble 
>   section seemed not to work well on my particular unit, so I 
adjusted 
>   this by ear to a minimum of noise and a reasonable effect level, 
>   skipping the specified values here.
> 
>   9) Tuning of Voice boards: Looking on my Voice boards I found no 
>   temperature compensation diode, it is printed on the board but 
not 
>   fitted. But tuning my unit was quite easy finally, after 
completing the 
>   tuning procedure it is in tune immediately when switched on and 
stays 
>   like this pretty well. It seems I have some magic VCOs...
> 
>   Now the only issue left is to replace a bulb in on of the program 
>   buttons, but this should be not a big problem,
> 
>   cheers, Gregor
> 
> 
> 
>    
> 
> [Non-text portions of this message have been removed]
>