Synth-DIY Yahoo! Groups Archives

Thread

Refurb of 300030

2014-08-27 by w.james.meagher@...

Hello Paul et autre!

I have acquired Polaris SN 300030 in a state of limited functionality (it makes noise, but that's about it), and am wondering if I should look out for anything specific with such an early SN while I have it open and am replacing the membrane panels, batteries, and giving it a good clean?

Also, I am interested in replacing all the LEDs with white or blue ones, but am having difficulty finding a suitable replacement in those colours that won't be blindingly bright in a dimly lit room (made that mistake with my last Polaris refurb). Curious if anyone has any ideas on this?

Thanks for any and all ideas, suggestions and advice,
James

P.S. Did anything ever come of the redesigned output board that was once being talked about?

Sent from my iPhone

RE: [chromapolaris] Refurb of 300030

2014-08-27 by Paul D. DeRocco

> From: James Meagher
>
> I have acquired Polaris SN 300030 in a state of limited
> functionality (it makes noise, but that's about it), and am
> wondering if I should look out for anything specific with
> such an early SN while I have it open and am replacing the
> membrane panels, batteries, and giving it a good clean?

Reseat connectors, and perhaps even socketed chips. Measure power supply
voltages (and check for ripple if you have access to a scope). Do all
calibrations. Take apart the keyboard and clean the boards and the insides
of the dome switches. If you have access to an EPROM programmer, reprogram
the EPROMs to make sure they're not fading or have old buggy code.

> Also, I am interested in replacing all the LEDs with white or
> blue ones, but am having difficulty finding a suitable
> replacement in those colours that won't be blindingly bright
> in a dimly lit room (made that mistake with my last Polaris
> refurb). Curious if anyone has any ideas on this?

The LEDs are driven directly off LS-TTL shift registers, with no
resistors. This is the absolute cheapest way to drive LEDs, but you can't
really know how bright a particular LED will be without trying it. You'll
just have to buy one of each LED that you can find in that package, and
try them out.

> P.S. Did anything ever come of the redesigned output board
> that was once being talked about?

No. However, I'll be doing a small production run of my Digital Chroma
boards in the next couple of months, and I'll bug my friend to include his
little board in the order. He's just been busy with other stuff.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...

Re: [chromapolaris] Refurb of 300030

2014-09-02 by w.james.meagher@...

Thanks for all that info and advice Paul!

I've done everything you suggested (except reprogramming the EPROMS because I don't have a programmer), and am about to put everything back together.

I'm wondering now if you think it advisable to remove the sockets (that the ribbons attach to), from the PCB so the ribbon connection ends don't need to bend to attach to them. This is what I did on my previous Polaris restoration where I DIDN'T replace the panels, but instead trimmed all the ribbon connectors shorter (past where they were cracking), and removed all the sockets from the PCB so those trimmed ribbon connectors wouldn't have to bend at all. I know these are new panels I've installed, but I'm still thinking perhaps they'll live longer if they aren't made to bend in a U to connect to the sockets.

As a complete aside, if you ever had a few replacement panels made with that original ARP-y yellow/orange/red color scheme I'd buy another set in a heartbeat!

Cheers,

James

Sent from my iPhone

On Aug 27, 2014, at 12:50, "'Paul D. DeRocco' pderocco@... [chromapolaris]" <chromapolaris@yahoogroups.com> wrote:

> From: James Meagher
>
> I have acquired Polaris SN 300030 in a state of limited
> functionality (it makes noise, but that's about it), and am
> wondering if I should look out for anything specific with
> such an early SN while I have it open and am replacing the
> membrane panels, batteries, and giving it a good clean?

Reseat connectors, and perhaps even socketed chips. Measure power supply
voltages (and check for ripple if you have access to a scope). Do all
calibrations. Take apart the keyboard and clean the boards and the insides
of the dome switches. If you have access to an EPROM programmer, reprogram
the EPROMs to make sure they're not fading or have old buggy code.

> Also, I am interested in replacing all the LEDs with white or
> blue ones, but am having difficulty finding a suitable
> replacement in those colours that won't be blindingly bright
> in a dimly lit room (made that mistake with my last Polaris
> refurb). Curious if anyone has any ideas on this?

The LEDs are driven directly off LS-TTL shift registers, with no
resistors. This is the absolute cheapest way to drive LEDs, but you can't
really know how bright a particular LED will be without trying it. You'll
just have to buy one of each LED that you can find in that package, and
try them out.

> P.S. Did anything ever come of the redesigned output board
> that was once being talked about?

No. However, I'll be doing a small production run of my Digital Chroma
boards in the next couple of months, and I'll bug my friend to include his
little board in the order. He's just been busy with other stuff.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...

RE: [chromapolaris] Refurb of 300030

2014-09-02 by Paul D. DeRocco

> From: James
>
> I'm wondering now if you think it advisable to remove the
> sockets (that the ribbons attach to), from the PCB so the
> ribbon connection ends don't need to bend to attach to them.
> This is what I did on my previous Polaris restoration where I
> DIDN'T replace the panels, but instead trimmed all the ribbon
> connectors shorter (past where they were cracking), and
> removed all the sockets from the PCB so those trimmed ribbon
> connectors wouldn't have to bend at all. I know these are new
> panels I've installed, but I'm still thinking perhaps they'll
> live longer if they aren't made to bend in a U to connect to
> the sockets.

I don't think there's anything wrong with bending the tails into an
S-curve. Real Mylar shouldn't have a problem with that. The old Polaris
panels were made out of some other kind of plastic, I believe, which
didn't age well, especially if bent. And the new panels have an insulation
layer over most of the tails to protect the ink, which would be hard to
remove without taking the ink with it.

> As a complete aside, if you ever had a few replacement panels
> made with that original ARP-y yellow/orange/red color scheme
> I'd buy another set in a heartbeat!

I wish there was a way to make really small quantities of panels, perhaps
using inkjet printing and laser cutting, but I haven't found anyone who
does that. The new Polaris panels are tooled, and the tooling is only
economically feasible if you're going to sell a significant number of
them.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...

Slightly OT: wtb Chroma I/O bd

2014-09-08 by Bob Grieb

Hi,

Didn't find a Yahoo Group for the Chroma, but maybe there are Chroma owners here as well. I recently purchased one of the first fifty ARP/Rhodes Chroma's. Unfortunately, the batteries had been allowed to leak for some years, and there were green flakes of corrosion on the traces of several of the pc bds. Luckily I got a replacement (old) CPU bd from the bay, and the voice bds appear to be workable.

The bd that really should be replaced is the I/O pcb. One of the key switch boards also took a hit. So I am looking for someone who has some spare Chroma pieces that they would be willing to part with. If you are saving an I/O bd as a source of particular replacement parts, I would be happy to carefully remove those parts for you and send them back. Things like the slide pot, or the DAC chips, for instance, that may be hard to find.

Anyway, if you can help me, please email. Thanks,

Bob

Re: [chromapolaris] Slightly OT: wtb Chroma I/O bd

2014-09-09 by David Clarke

> ... Didn't find a Yahoo Group for the Chroma, but maybe there
> are Chroma owners here as well...

There will be a few Chroma owners here - but the best/first place always
to go for Chroma-related topics will be the Rhodes Chroma web site
(http://www.rhodeschroma.com/).

The ChromaTalk mailing list is available there. The details are here:

http://www.rhodeschroma.com/?id=chromatalk

> ... The bd that really should be replaced is the I/O pcb. One of
> the key switch boards also took a hit. So I am looking for someone
> who has some spare Chroma pieces that they would be willing to part
> with.

The ChromaTalk mailing list will be the best place for a request like
this as many Chroma owners pick up 'extra' parts to have on hand 'just
in case' - any one or more might be willing to free up some items
(especially smaller items like the key switches).

They don't often come up - but perhaps triggered by your question, I do
see that there's an I/O board currently listed on eBay too.

Congratulations on your Chroma purchase.

David Clarke