Rhodes Chroma Polaris

--- In chromapolaris@yahoogroups.com, "Paul D. DeRocco" <pderocco@...> wrote:
>
> > From: wasteking1
> >
> > I tried your suggested volume test with a long sustained sound
> > and the volume slider --it seemed to attenuate in a normal way--
> > no early cut out. and i repeat, the non-touch sensitive playing  is fine
> >  I was wondering if each of the 6 voices had a seperate chip(?)
> > that dealt with interpereting the volume of the touch sensitivity
> > signal  that wouldnt affect the normal full signal. [would that
> > be the Zx09?]  is this touch /volume  located in the sample/hold
> > area? I have the schematics, but that doesnt really descrbe the
> > function of the  various parts. [ I also have a dead polaris to
> > scavenge chips from  if that would be helpful ] sorry, but i have
> > no scope, just a meter.
> 
> When you say "volume slider", I wonder if you're talking about the Master
> Volume. I was talking about the Volume parameter in the Assignable Control
> section. The Master Volume manipulates the gain of the single amplifier on
> the output board, and has nothing to do with the sample-and-holds or the
> individual channels.
> 
> All interpretation of touch sensitivity is done inside the CPU; it merely
> delivers a single control voltage to each channel for Pitch A, Pitch B,
> Width A, Width B, Cutoff and Volume. I can't imagine any mechanism that
> would allow these to function normally for non-touch-sensitive sounds, but
> function unevenly on touch-sensitive sounds in a way that correlates with
> the voice number as opposed to the key number.
> 
> With no notes sounding, the voltage on pin 7 of all six Zx03 chips should be
> slightly negative; if it's much more negative on the voice in question, then
> you've narrowed the problem considerably. This can be tested with a
> voltmeter.
> 
> --
> 
> Ciao,               Paul D. DeRocco
> Paul                mailto:pderocco@...
>
you were right--i was testing with the master volume slider--- using the
assignable volume it cuts out at about 40% of the way up . At the risk of
sounding even more stupid-- i was wondering how i would check for negative
voltage --crossing pin 7 with what? ground? and my simple anaolg needle 
radioshak meter  showed +3 volts when i crossed from the battery to pin 7 on all zx03 chips.     [ but i could try swapping Zxo3 chips if they are the likely source] ..i assume
that voices 1-6 correspond to chips numbered z2o3-z703 in the 'X' place . of
course that places chip Z203 under the output board requiring unscrewing the
whole main circuitboard.