Rhodes Chroma Polaris

--- In chromapolaris@yahoogroups.com, "Paul D. DeRocco" <pderocco@...> wrote:
>
> > From: wasteking1
> >
> > i just got another polaris off ebay---it supposedly had only  a
> > keyboard contact problem which i was going to fix...but
> > apparently now that it arrived most of the controls are dead---
> > the LEDs go on but all the sliders  dont have any effect...ALL
> > sliders from volume to assignable. even the benders.  I can
> > change through all the programs (letters /numbers)  and it seemed
> > to go through  auto tune- [6 blinks] ... but i cant modify the
> > sounds. IT SEEMS THAT  ONLY 3 BUTTONS DO WORK... noise,
> > sine-square , and touch on/off for volume.
> >  there had been a ribbin wire repair from left to right board on
> > the lower connector ( using spliced in wire). but not the upper
> > smaller ribbon.
> > i have tested for a simple continuity accross the repaired ribbon
> > between the left and right board and it seems to be ok. any ideas
> > which ribbon (i assume a ribbon wire)  would be at fault to
> > affect this odd array of controls.  i have the service manual and
> > schematics, but they dont show this type of info clearly to me
> > (perhaps its in there somewhere?)
> 
> If none of the analog controls work, then the problem is something in common
> to all of them, which could be anything from the latch Z6 on the right panel
> board, the connectors on the big ribbon cable between the panel and the main
> board, or something in the A/D converter circuit on the main board. Since
> all analog inputs are multiplexed onto one line, this is the sort of thing
> that's difficult to diagnose without a scope, but easy to diagnose with one.
> 
> The first thing to do is to unplug and re-plug everything in sight, since
> connectors can come loose, or even develop dirty contacts over time. The
> only single thing that would affect both analog inputs and switches would be
> the main ribbon between the main board and the panel. You may get lucky, and
> that may fix it. If not, you'll probably need more than a multimeter to
> figure it out.
> 
> --
> 
> Ciao,               Paul D. DeRocco
> Paul                mailto:pderocco@...
>


thanks paul---it WAS a lose connector cable...the one labeled j-10.
it must have been jarred loose in shipment. now the controls work.

I was afraid it was those brittle mylar membrane ribbons which had been
repaired previously on this unit and didnt think of something way simpler. I
was suprised that those 3 buttons (noise,sine/square , and touch) were still
operative , that was what was confusing me . perhaps a couple pins still had
good contact. anyway --- you are the man.

'long live the polaris'