OldSynths

I don't have any Soloist info...  not even a  block diagram but if you are getting a low note and lower when the octave down button is on, then it souds like the osc. and octave button are working but the cv from the kb and tuning knob are not making it to the osc. cv input.  If I remember correctly, there are no "scanning chips...".  It is a simple voltage divider (probably 100 ohm reisistor at each key contact with the high voltage end controlled by the tuning knob) and the output of that is not making it to the cv in of the osc. or the cv input section of the osc. is blown.  

I've seen various sources for schematic onthe web...  the thing to do would be to find the output of the keyboard voltage and measure it to see if it changes as you hit different keys and then trace that signal to the osc. and see where the signal quits.  I would bet a broken wire.

Ed

dshoemaker93 wrote:

Hi Ed,

Are you suggesting that the keyboard scanning chips might be the culprit?  Sending
no note/octave information?  Or do you mean that no voltage *at all* is reaching the
oscillator?

Thanks,
David

--- In oldsynths@yahoogroups.com, Ed Edelenbos <eded@s...> wrote:
> Sounds to me like the V into the osc. isn't making it... 
>
> Ed
>
> David Shoemaker wrote:
>
> > Hi everyone,
> >
> > I took delivery on my ARP Pro Soloist today.  I knew it would need
> > repairs when I bought it, and here's what I've discovered so far.  I
> > would really appreciate any suggestions on the next diagnostic/repair
> > steps.  I have a hunch this is not going to be that complicated.
> > (crossing fingers)
> >
> > Here's the problem:  It powers up correctly.  Every key triggers a
> > sound, but the pitch does not change from key to key.  The sound it
> > *does* make is a very low cycle tone, much lower than any keyboard
> > should make.  It does not seem to be an LFO, because:  The pitch
> > changes in octaves (roughly) as I move the octave shift lever.   Of
> > course, the pitch is so low to start with that the "normal" and "low"
> > octave settings are just clicks.  The pitch does NOT change, as far as
> > I can tell, when I adjust the tuning trimpot, nor does it respond to
> > the front panel tune "knob".
> >
> > The preset switches DO change the timbre of the sound, as if the
> > filters are working correctly.  The volume slider works normally.  The
> > "touch sensitivity" switches act as they should EXCEPT for the pitch
> > bend, and possibly the vibrato (hard to tell with such a low pitch
> > though).  Portamento does NOT seem to work.
> >
> > The presets I would expect to be in a lower octave seem to be so, e.g.
> > "Bass", "Tuba".
> >
> > What I've done so far:
> >
> > --I replaced the aluminum caps in the power supply, and the output from
> > the power supply is normal.
> > --I very carefully cleaned all the oxidation off the J-wires and the
> > contact bar.  Key triggering is almost perfect as far as I can tell.
> >
> > Can anyone offer any suggestions?  I have a couple sources for spare
> > parts if I need them--I'm just not sure what to test/fix next.
> >
> > Thanks very much,
> > David Shoemaker
> >
> >



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