Hi Paul,

> I think I prefer to buy a bunch (minimum 25, perhaps 50) on spec,
> and just sell them on eBay, since I'll have to be individually
> package them and reship them.

Your preference runs the show here - I just wanted to make the option known on the off-chance a groupbuy hadn't been considered.

> I doubt they'll cost that much, but that's not based on any actual
> quotes.

Sure thing - I put that figure up as the amount where I would start to dither over buying a replacement panel. If the price was under $200 I would definitely order one. If it was under $150 I would buy two as extra insurance... If the replacement panel could be produced for under $100 I would order 3-5 of them to stockpile for future repair opportunities.

> I have no expertise in plastics or chemistry, but my experience is
> that membrane switches (other than the top surface) are normally
> made out of polyester (Mylar), and this has a pretty much unlimited
> lifetime.

DX-7, JX-10, JX-8P and others here are just fine with their membrane switches and plastic ribbon harnesses- If treated with respect and kept out of direct sunlight (UV) these should last as long as the rest of the instrument... But as we all know, they don't on Polaris.

> The Polaris panels failed because they were either made out of
> something else (exactly what that may be is lost in the files of
> Fender of Japan), or because of some interaction between the green
> masking and the plastic.

Aha. Very plausible theory regarding the green masking - I'm not plastics expert but it certainly makes sense to me.

> I intend to leave the tails unmasked (since silver oxide is
> harmless), and to make sure that whoever makes these doesn't use
> anything nonstandard. That's about all I can do.

Great news. Thanks again for all your efforts on this front!

Tony

--- In chromapolaris@yahoogroups.com, "Paul D. DeRocco" <pderocco@...> wrote:
>
> > From: syntegrator
> >
> > When it gets closer to a reality, you can set the whole
> > system up at groupbuy.com - This is how Andrew Jury and Jed
> > Jorgensen handled their Polysix replacement mainboard project
> > over in the Polysix group and it worked really well. I ended
> > up buying 10 of these PCBS because as more people signed on
> > the unit cost kept dropping and as we ordered more the price
> > would drop again... :)
>
> I think I prefer to buy a bunch (minimum 25, perhaps 50) on spec, and just
> sell them on eBay, since I'll have to be individually package them and
> reship them.
>
> > I completely agree with James - My Polaris still has a fully
> > functional membrane panel, but I know the Synth Reaper awaits
> > this classic unless I can arrange to have a backup membrane
> > panel standing by. If such a part were to cost under $250
> > that would be a certain purchase for me, but I understand
> > that low volume runs could mean it costing more than that.
>
> I doubt they'll cost that much, but that's not based on any actual quotes.
>
> > While I am posting - I take it that the replacement design
> > will use ribbons with a plastic formulation that is less
> > prone to cracking with age? I have Roland synths from the 80s
> > and 90s that use these kind of connectors and none of them
> > have aged appreciably so surely the original issue is
> > specific to the Polaris and its choice of ribbon connector supplier?
>
> I have no expertise in plastics or chemistry, but my experience is that
> membrane switches (other than the top surface) are normally made out of
> polyester (Mylar), and this has a pretty much unlimited lifetime. For
> instance, the original Chroma membrane panels have exhibited no such
> failures. The Polaris panels failed because they were either made out of
> something else (exactly what that may be is lost in the files of Fender of
> Japan), or because of some interaction between the green masking and the
> plastic. I intend to leave the tails unmasked (since silver oxide is
> harmless), and to make sure that whoever makes these doesn't use anything
> nonstandard. That's about all I can do.
>
> --
>
> Ciao, Paul D. DeRocco
> Paul mailto:pderocco@...
>