Yamaha CS80

Hi.

Finally I can continue my restoration. 
It was a IGO151 VCA that distort the waveforms!
Thanks erikfromhere.

Now I was the last problem on waveform Pulse,in the same Mboard five 
on Channel One.
In practice with the preset Funky 3, the envelope seems slow compared 
to other items or out of Phase.

It's a fault PWM section...

In the Panel mode with the Slider PM (the third slider of the section 
PWM) all up, the signal disappear!
And moving  the "speed" slider  the signal goes out of phase with the 
same effect that I noticed in the preset "funky 3"


Any suggestions?




--- In yamahacs80@yahoogroups.com, "erikfromhere" <moogsynthex@...> 
wrote:
>
> My guess would be the saw- and/or pulse-gate is always open. Try 
> replacing the FET6 or FET7 (2SK30) or TR6 or TR7 (2SA561). However, 
> you say the waveform can be heard even when the vcf-volume is 
> closed. Then I would say the sinewave is not a pure sinewave. Does 
> the waveshaper output a perfect sine ? You'll need a scope for that 
> on pin 2 of ic9. Or does vca3 (IG00151) distort the sine-wave ? Try 
> replacing vca3...
> Good luck.
> 
> --- In yamahacs80@yahoogroups.com, "oberheim64" <tommysalsero@> 
> wrote:
> >
> > Hi. 
> > My name is Tommaso, live in Italy and I had in the last 10 years 
> > three CS80! 
> > The second was in perfect condition and 
> > I sold to a dear friend in Italy. 
> > The third I found recently, I could not live without a CS!
> > I started with the restoration.
> > Now the beast was in perfect condition externally, perfectly 
tuned 
> > but with a  little problem on the five Mboard on Channel One.
> > With the Sine wave only (VCF volume closed)
> > In addition to sine,I Feel another waveform  similar to sawtooh.
> > And the waveform (Saw e Square) of the channel one are closed!
> > I Change all the IGO chips in the Board,but without any positive 
> > effect.
> > Then I changed the polarize electrolytic capacitors.
> > 
> > Same problem...
> > 
> > Now,they may be the 1 Uf 50V not polarized capacitors?
> > Or the other caps?
> > 
> > Sorry but I do not have an oscilloscope.
> > Some suggestions?
> >
>