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--- In chromapolaris@yahoogroups.com, "Paul D. DeRocco" <pderocco@...> wrote:
>
> > From: gopalsulleniii
> >
> > I have a chroma Polaris in pretty good condition. I just
> > replaced the front panels with new ones that I purchased from
> > Paul. Now I am able to use the lower function button and
> > several of the other buttons that did not work at all before.
> > I still have one problem, however. The upper function button
> > does not appear to be working correctly and I am needing some
> > help troubleshooting the cause.
> >
> > I do not seem to be able to get the unit to go into the
> > diagnostics mode. I can press the upper function button and
> > it will not stay lit. If I tap it repeatedly very quickly
> > occasionally I can get it to light and stay lit. However,
> > when I try to initiate the diagnostic mode the keyboard will
> > freeze up.
> >
> > I have tested some of the lower function buttons and
> > combinations and and able to get the adjustments mode to work
> > where I can modify voices. That is really satisfying.
>
> So when you hold your finger on UPPER FUNCTION, does its LED light up until
> your take your finger off? Or does it flash? Or does it do nothing usually?
> Do all the other switches work normally? Does the instrument auto-tune
> successfully, and sound normal?
>
> Since you just did the membrane switch replacement, that's where I'd start
> to look. Sometimes, the silver ink traces on the tails are a little off
> center, and they don't line up very well with the contacts in the
> connectors. It might be a good idea to carefully pull them out of the
> connectors and plug them in again, rechecking the alignment. Since your
> problem is with a right panel switch, and its connectors are on the long
> edge of the board, you shouldn't have to remove the left panel board.
>
> Also, connectors are the #1 source of problems, so unplugging and reseating
> other connectors, like the big ribbon to the panel, and the power supply
> connectors, is worth doing.
>
> There could be more than one problem, too. When you say that pressing UPPER
> FUNCTION doesn't work but tapping it sometimes does, that makes me think
> that some noise is interfering with one or more switch lines, perhaps an
> unstable power supply voltage. And when you say the keyboard freezes when
> you go into diagnostic mode, that makes me think the EPROMs might be
> dropping bits, which can only be fixed by reprogramming them.
>
> --
>
> Ciao, Paul D. DeRocco
> Paul mailto:pderocco@...
>