Synth-DIY Yahoo! Groups Archives

New Choma Polaris not working!!!

2006-11-30 by Bob

Hi there. I just got a Chroma Polaris on Ebay, and it isn't working
right. When you turn it on many of the led's light up, but the same
ones don't come on every time the switch is turned on and off again.
Sometimes the same ones will come on a few times in a row but then if
you leave it off for a couple of minuites a different combination of
lights will come on. The keyboard makes no sound whatever, and pushing
any of the buttons will not turn on or off any of the leds. The
keyboard appears to be in great condition, and the membrane switches
don't look worn at all. I'm pretty puzzled as to what could be going
on, or what to do about it. You would think even if the membrane
switches were shot, the keyboard would at least turn on with one patch
loaded. Anyone else had a similar problem? Thanx for any help you may
have. -Bob

RE: [chromapolaris] New Choma Polaris not working!!!

2006-12-01 by Paul D. DeRocco

> From: Bob
>
> Hi there. I just got a Chroma Polaris on Ebay, and it isn't working
> right. When you turn it on many of the led's light up, but the same
> ones don't come on every time the switch is turned on and off again.
> Sometimes the same ones will come on a few times in a row but then if
> you leave it off for a couple of minuites a different combination of
> lights will come on. The keyboard makes no sound whatever, and pushing
> any of the buttons will not turn on or off any of the leds. The
> keyboard appears to be in great condition, and the membrane switches
> don't look worn at all. I'm pretty puzzled as to what could be going
> on, or what to do about it. You would think even if the membrane
> switches were shot, the keyboard would at least turn on with one patch
> loaded. Anyone else had a similar problem? Thanx for any help you may
> have. -Bob

The computer simply isn't running. There are lots of things that could cause
this, but at the very least you should open it up and reseat all connectors.
I'd suggest pulling and reseating the CPU and the EPROMs, too, just to clean
their contacts. It's even possible that the EPROMs themselves have faded,
and need to be reburned or replaced. And there could be other hardware
failures, too.

--

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

Re: [chromapolaris] New Choma Polaris not working!!!

2006-12-01 by Astraeus000@aol.com

Did you open it up and check to make sure that the internal battery hasn't had a meltdown on the CPU board?? Unfortunantly this is the case with many old synths that are left in storage for long periods of time without removal of the old batterys. Chromas, and I believe the Polaris as well are also known to have faulty power supplies. In fact, my Chroma has a doctor appointment next week to replace the old one. Major frustrations no doubt about it.

regards,

-Richard

-----Original Message-----
From: pderocco@...
To: chromapolaris@yahoogroups.com
Sent: Thu, 30 Nov 2006 7:38 PM
Subject: RE: [chromapolaris] New Choma Polaris not working!!!

> From: Bob
>
> Hi there. I just got a Chroma Polaris on Ebay, and it isn't working
> right. When you turn it on many of the led's light up, but the same
> ones don't come on every time the switch is turned on and off again.
> Sometimes the same ones will come on a few times in a row but then if
> you leave it off for a couple of minuites a different combination of
> lights will come on. The keyboard makes no sound whatever, and pushing
> any of the buttons will not turn on or off any of the leds. The
> keyboard appears to be in great condition, and the membrane switches
> don't look worn at all. I'm pretty puzzled as to what could be going
> on, or what to do about it. You would think even if the membrane
> switches were shot, the keyboard would at least turn on with one patch
> loaded. Anyone else had a similar problem? Thanx for any help you may
> have. -Bob

The computer simply isn't running. There are lots of things that could cause
this, but at the very least you should open it up and reseat all connectors.
I'd suggest pulling and reseating the CPU and the EPROMs, too, just to clean
their contacts. It's even possible that the EPROMs themselves have faded,
and need to be reburned or replaced. And there could be other hardware
failures, too.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@ix. netcom.com

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Re: [chromapolaris] New Choma Polaris not working!!!

2006-12-01 by David Clarke

> From: "Bob" <corian7@...>
>
> ...When you turn it on many of the led's light up,
> but the same ones don't come on every time the switch
> is turned on and off again. ...

This really sounds like a classic case of the 'reset level' adjustment
("DC OK Threshhold") on the power supply being off.

Specifically, it could be a little low, causing the CPU to wake up
before it
should. If this is the source of the problem, then it is something easy
to
address (and is covered in the Service Manual, ref: Section 6 -
Adjustments
and Checkout) [The service manual is available in PDF form at
http://www.rhodeschroma.com/?id=polaris ]