I'm back at the CS-80 repair. I ended up removing TU from the KAS board but before I was
getting 'nearly' the same pitch across the whole keybed, and the voltage at TU was
13.37v. I removed TU and the pitch totally changed on the keys. I was getting much more
variation of pitch across the keybed, just octave issues. I replaced TU back onto the KAS
board and the pitch stayed pretty much the same as this new way now. Here is a clip of me
playing every key up the keybed:
http://www.heathfinnie.com/media/cs80issue.mp3The voltage at TU dropped some as well after removing it and the resoldering it. It's now
at 10.37v and VR3 on the BA board has 0 effect on this voltage like it should. I should also
note that the tuning knob and pitch ribbon still have no effect on the pitch. I tried to do
the adjustment of the KAS board and here are the voltages I'm getting:
TU: 10.37v (should be 4v)
Octave Ladder network - should be 125.0mv at Pin 13 on IC2 I'm getting -4.10v
Voltage follower: Pin 6 IC3: Should be 125.0mv, I'm getting 2.55v
Note Ladder Network: Pin 38 IC2: Should be +132.4mv, I'm getting 2.55v
On the BA board I've replaced IC1, 2, 3 and 4. TR29 and both Fets. I highly doubt the
problem is on the KAS board as I replaced it entirely from another one and the problem
was exactly the same.
Thanks!
--- In yamahacs80@yahoogroups.com, "willgregori" <will.gregory@...> wrote:
>
> Had the same problem, on my cs80 TR29 was a broken on the BA board,
>
> good luck
>
> --- In yamahacs80@yahoogroups.com, "Heath Finnie" <heathfinnie@>
> 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?
> >
> > Thanks!
> >
>