Yamaha CS80

OK. What you really need to do here then is isolate this fault.



First thing i need to know is if you have replaced any of the 4558
(4158) in the synth.



Next thing to do if lift the 4 pink +8.5 wires to the KAS and the 4
yucky green -6.5 and separate them from each other.

Find the feeds from the psu for both and test. If ok re-attach just
them. Test the remaining 3 wires of each color to see if there is
any standing dc on them. If there is, Leave that one floating and
solder the rest back onto the KAS.



Then find what section of the 80 this wire feeds.



Next, email me again



Kent



KSR






KSR


--- In yamahacs80@yahoogroups.com, "kent_spong" <kent_spong@...>
wrote:

>
>
> Your problem is on the BA board by the sounds of it. Pull the TU

and

> see if the wire has 13ish volt sitting on it.
>
>
>
>
> --- In yamahacs80@yahoogroups.com, "Heath Finnie" <heathfinnie@>
> wrote:
> >
> > Hi David,
> >
> > All three fuses are good and all my supply voltages are there.

As

> I said, I know the KAS
> > board is good because I replaced the entire board after this
> problem started and its still
> > there.
> >
> > I also tried calibrating the KAS board and I'm getting very
> strange things going on. For
> > instance on wire TU the calibration says I should be getting 4.v
> for a reference voltage but
> > I'm getting almost 13v. None of the VR's are doing anything

either.

> >
> > --- In yamahacs80@yahoogroups.com, David Rogoff <david@> wrote:
> > >
> > > I've had CS80s do this when I've shorted something and blown

one

> of the
> > > DC fuses in the power supply. Are you sure all the supply
> voltages are
> > > there?
> > >
> > > Heath Finnie wrote:
> > > > This is a big question here. The CS-80 I'm working on will
> barely change pitch all the
> > way up
> > > > the keyboard now. Some keys will play a little lower but not
> much. Now here are the
> > > > symptoms:
> > > >
> > > > I replaced most all the IC's on the sub board. I replaced

the

> entire KAS board with a
> > working
> > > > one. Problem does not change.
> > > >
> > > > The pitch ribbon is having no effect on pitch. Neither is

the

> pitch knob.
> > > >
> > > > The channel 2 detune IS working as is the footing sliders.
> > > >
> > > > Ring modulator is working, sub oscillator is working and so

is

> all the waveforms.
> > > >
> > > > Any of the tech guys able to help?
> > > >
> > > >
> > > >
> > >
> >
>