Rhodes Chroma Polaris

Hi,

I have 3 Chroma polaris synths, one has never been used (Bought for a spare in 1986) I keep it in is flight case and change the battries once a year.
just changed them and when I turned the polaris on the lights just freeze and i cant change any buttons?
I seem to remember this may be a power supply reglulator problem, as I think this polaris was imported to the uk for the the states

Any Idea's

Peter

> From: peterjamesstephen
>
> I have 3 Chroma polaris synths, one has never been used
> (Bought for a spare in 1986) I keep it in is flight case and
> change the battries once a year. just changed them and when I
> turned the polaris on the lights just freeze and i cant
> change any buttons?
> I seem to remember this may be a power supply reglulator
> problem, as I think this polaris was imported to the uk for
> the the states

It could be a lot of things. Fortunately, many of the things that it could
be are merely mechanical issues with connectors or IC sockets. Even if you
have absolutely no electronic tools, try reseating all the connectors (but
don't touch the membrane switch tails). If still no joy, then try prying the
memory chips up slightly and pushing them back down. (Do these things with
the power off, obviously.) If you have a voltmeter, you can check the
various supply voltages, and also make sure the DC OK and AC OK signals from
the power supply are high.

--

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

Hey Peter,

I've also encountered this problem with my Polaris intermittently. The power supply regulator may be the issue. I'm not certain, but it might also have something to do with those fragile membrane ribbons attached between the circuit boards of the control panel. Mine cracked over time, and recently I had some re-soldering done which fixed most of the problems for the time-being. Whenever my Polaris froze, I'd turn it off and unplug the power for a while. Most of the time this worked, but you may have to experiment switching it on and off until it finally boots. :P I know that sounds cheesy, but I hope it might at least provide some help.

~Ryan



To: chromapolaris@yahoogroups.com
From: sincity@...
Date: Mon, 22 Nov 2010 16:46:40 +0000
Subject: [chromapolaris] Polaris lights freeze when turned on

 

Also...(you may already know this.) Before you mess with the RAM chips, be sure you have a reliable backup of everything in memory, or you could lose it. If for some reason you need to re-seat any of the chips, you'll need to disconnect the battery backup cable from the J15 jumper so that power isn't being sent to your RAM while you pry it out.


Best wishes.
~Ryan

> From: Ryan Freer
>
> Also...(you may already know this.) Before you mess with the
> RAM chips, be sure you have a reliable backup of everything
> in memory, or you could lose it. If for some reason you need
> to re-seat any of the chips, you'll need to disconnect the
> battery backup cable from the J15 jumper so that power isn't
> being sent to your RAM while you pry it out.

I wasn't suggesting removing the chips, just dislodging them a millimeter or
so. In general, this is something that you can do even with the power on,
although it's wise to turn the main power off just in case the screwdriver
slips. And you might as well do it with the power off because afterwards
you'll have to cycle the power anyway to see if it boots.

--

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

> ... when I turned the polaris on the lights just freeze and i cant
> change any buttons? ...

Following up to the responses of others, this can also occur because of
the 'reset level' adjustment ("DC OK Threshhold") on the power supply
being incorrect.

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 ]

I second this.

--- In chromapolaris@yahoogroups.com, "David Clarke" <ac151@...> wrote:
>
> > ... when I turned the polaris on the lights just freeze and i cant
> > change any buttons? ...
>
> Following up to the responses of others, this can also occur because of
> the 'reset level' adjustment ("DC OK Threshhold") on the power supply
> being incorrect.
>
> 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 ]
>

I've seen this happen intermittently on *most* of the polaris' I've worked on! Very common. Mine does it now and then. Sometimes if you wait 20 seconds the lights go off and it plays normally. I've never investigated a cure for it so if anyone finds it I'll ad it to my website of course which has vast resources on many vintage synth repair issues if you haven't seen it. -Bob sounddoctorin.com/synthtec/synth.htm

--- In chromapolaris@yahoogroups.com, "picardjeanluc69" <picardjeanluc69@...> wrote:
>
> I second this.
>
>
>
> --- In chromapolaris@yahoogroups.com, "David Clarke" <ac151@> wrote:
> >
> > > ... when I turned the polaris on the lights just freeze and i cant
> > > change any buttons? ...
> >
> > Following up to the responses of others, this can also occur because of
> > the 'reset level' adjustment ("DC OK Threshhold") on the power supply
> > being incorrect.
> >
> > 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 ]
> >
>