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Chroma Polaris Lights up, but makes no sound.

Chroma Polaris Lights up, but makes no sound.

2014-04-18 by merolasteve

Hi everyone.  I joined up in anticipation of buying a non-working Polaris.  I now have it in my possession.

It is in great cosmetic, but non-working shape.  When I power it on just about all the LEDs light up, but that is about it.  Pressing the buttons does nothing and the keys and sliders don't do anything either.  I tried the cold and warm reset, but nothing happened.  I have not done the full reset, although since the buttons do not appear to work I don't know if that would work.  I wanted to check here to see what the next step is.  I did a few searches, but could not find a similar problem.  I have not opened it up yet because I heard that can possibly damage the membrane connections further.  The only sound is a constant, faint hum/noise sound.  Any suggestions on where to start would be appreciated.

Thank you
Steve

Re: [chromapolaris] Chroma Polaris Lights up, but makes no sound.

2014-04-18 by w.james.meagher@...

The first thing to do is to open it and check those membrane connections. Watch the videos online about it first so you know what you're looking for. I believe they were made by Bob Weigel. Though Bob shows how to repair them, I think it's a good idea to by the new replacement panels sold by Paul here.

Sent from my iPhone

On Apr 18, 2014, at 17:37, merolasteve <no_reply@yahoogroups.com> wrote:

 

Hi everyone.  I joined up in anticipation of buying a non-working Polaris.  I now have it in my possession.

It is in great cosmetic, but non-working shape.  When I power it on just about all the LEDs light up, but that is about it.  Pressing the buttons does nothing and the keys and sliders don't do anything either.  I tried the cold and warm reset, but nothing happened.  I have not done the full reset, although since the buttons do not appear to work I don't know if that would work.  I wanted to check here to see what the next step is.  I did a few searches, but could not find a similar problem.  I have not opened it up yet because I heard that can possibly damage the membrane connections further.  The only sound is a constant, faint hum/noise sound.  Any suggestions on where to start would be appreciated.

Thank you
Steve

Re: [chromapolaris] Chroma Polaris Lights up, but makes no sound.

2014-04-19 by Bob Grieb

Sounds like possibly the CPU is not executing code properly, which could be
caused by a lot of things.  Do you have an oscilloscope?

First thing is to download the service manual from the web and get a little familiar
with the circuitry and where different things are located.

If your problem is the membranes, it's not too hard to make the same connections as
a few of the switches by other means, to see if the rest of the synth is working.

But if most of the LEDs come on and stay on, that does not sound to me like a
membrane issue.

Once you get things up and running, I would agree that replacing the membranes with new ones from Paul is a really good idea.

Bob


From: merolasteve <no_reply@yahoogroups.com>
To: chromapolaris@yahoogroups.com
Sent: Friday, April 18, 2014 6:37 PM
Subject: [chromapolaris] Chroma Polaris Lights up, but makes no sound.



Hi everyone.  I joined up in anticipation of buying a non-working Polaris.  I now have it in my possession.

It is in great cosmetic, but non-working shape.  When I power it on just about all the LEDs light up, but that is about it.  Pressing the buttons does nothing and the keys and sliders don't do anything either.  I tried the cold and warm reset, but nothing happened.  I have not done the full reset, although since the buttons do not appear to work I don't know if that would work.  I wanted to check here to see what the next step is.  I did a few searches, but could not find a similar problem.  I have not opened it up yet because I heard that can possibly damage the membrane connections further.  The only sound is a constant, faint hum/noise sound.  Any suggestions on where to start would be appreciated.

Thank you
Steve



RE: [chromapolaris] Chroma Polaris Lights up, but makes no sound.

2014-04-19 by Paul D. DeRocco

> From: merolasteve
>
> Hi everyone. I joined up in anticipation of buying a
> non-working Polaris. I now have it in my possession.
>
> It is in great cosmetic, but non-working shape. When I power
> it on just about all the LEDs light up, but that is about it.
> Pressing the buttons does nothing and the keys and sliders
> don't do anything either. I tried the cold and warm reset,
> but nothing happened. I have not done the full reset,
> although since the buttons do not appear to work I don't know
> if that would work. I wanted to check here to see what the
> next step is. I did a few searches, but could not find a
> similar problem. I have not opened it up yet because I heard
> that can possibly damage the membrane connections further.
> The only sound is a constant, faint hum/noise sound. Any
> suggestions on where to start would be appreciated.

The FIRST thing to do is to open it up and see if you've got the early
power supply version that has three trimpots on it. If so, the problem may
be that the DC OK threshold is set incorrectly, so the CPU is being held
in the reset state. This is a very common situation, and easy to fix. If
LED CR10 is off, then turn R17 CW until it turns on, and go maybe 5 or 10
degrees past that point.

If the LED is already on, or you've got the newer power supply with only
two trimpots, then it will take a more thorough diagnosis.

Just opening the unit up shouldn't damage the membrane switch tails, as
long as you don't accidentally bump them as you set the control panel
assembly down.

--

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

RE: [chromapolaris] Chroma Polaris Lights up, but makes no sound.

2014-04-19 by merolasteve

Thanks for the quick replies. I will look at the LEDs and trimmers when I am home again tomorrow. A few things I noticed: a crack in the smaller flat cable for the membrane...bummer. the batteries were pretty nasty. I removed them and brushed the contacts clean. Other than a little corrsion and leakage around the batteries it is very clean. I do have a scope, but really have only used it for viewing wave forms. I also have a meter and am pretty good soldering/desoldering skills if needed...but lets hope I don't have to do any of that. More to come Thanks again all. I really appreciate it. Steve

Re: [chromapolaris] Chroma Polaris Lights up, but makes no sound.

2014-04-19 by Robert Stewart

From my understanding, when the batteries go flat you loose all the stored settings and have to go through an elaborate calibration procedure to get it going again.
(Section 6 in the Service Manual: What to do if you lose your memory)
I have a similar issue, but I can't recalibrate until I've replaced the membrane switches, as some of the (Vital) switches aren't working)


On 19/04/2014 02:45, merolasteve wrote:
 

Thanks for the quick replies. I will look at the LEDs and trimmers when I am home again tomorrow. A few things I noticed: a crack in the smaller flat cable for the membrane...bummer. the batteries were pretty nasty. I removed them and brushed the contacts clean. Other than a little corrsion and leakage around the batteries it is very clean. I do have a scope, but really have only used it for viewing wave forms. I also have a meter and am pretty good soldering/desoldering skills if needed...but lets hope I don't have to do any of that. More to come Thanks again all. I really appreciate it. Steve


RE: [chromapolaris] Chroma Polaris Lights up, but makes no sound.

2014-04-20 by Paul D. DeRocco

> From: merolasteve
>
> Ok. So the power supply has three trimmers. All LEDs except
> the following are constantly lit: Noise, Mod Lever Range, OSC
> 2 ENV, and A.

I was referring to the LED on the power supply. I guess it must be off, or
you'd have noticed it.

--

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

RE: [chromapolaris] Chroma Polaris Lights up, but makes no sound.

2014-04-20 by Paul D. DeRocco

> From: merolasteve
>
> Hi Paul. The power supply LED is on. I had never actually
> powered it on with the top off until just now. Steve

Too bad. That means you have something else that needs to be diagnosed.

Next step would be to unplug and reseat all the cables.

After that, I'd look at all the power supplies with a scope to make sure
they're within spec and don't have loads of ripple on them.

--

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

Re: Chroma Polaris Lights up, but makes no sound.

2014-04-22 by merolasteve

Just to follow-up.  I re-seated just about every cable.  I still need to re-seat the cables that connect to the panel PCBs.  I VERY carefully reseated the 2 flat foil cables on the right.  I might try and do the wire repair to the cracked far right cable while I save up some cash for new membranes.  So far the biggest mistake I made was not removing the batteries while reseating the RAM chips.  According to Paul it may or may not have damaged them.  No changes to the current problem is visible though.

My main problem seems to be that the computer has crashed.

I contacted Paul off list and asked a few questions while inquiring about the membranes.  I wanted to post some of it here so that in the future newbs like myself can see it when they buy non-working boards.  However, I am in this to learn as much as possible.  A lot of it comes from the Service Manual.

Things to test first:

-re-seat all cables
-re-seat chips, without the batteries installed and after caps are drained (I read this elsewhere)
-measure output voltages: +5V REF and + 5 DIG are adjustable and should be adjusted within about 1%; +12V ANA, -12V ANA, -5V should be within 5%
-measure AC OK (about 5V) and DC OK (at least 2.5V)
-for the above tests all cables should be connected and power should be on; for a ground connection, attach meter to ground lug sticking up near where the power cables plug into the main board.
-measure power supply ripple at 60Hz and 120Hz using a scope to see if there is significant ripple...I'm still learning about this one.
-refer to schematics for other locations to test power supply voltages

I have been too busy with my home-remodeling to do most of this, but will hopefuly get to it soon.  I ordered some leads for my scope and some DN5 DeOxit.

Re: [chromapolaris] Re: Chroma Polaris Lights up, but makes no sound.

2014-04-23 by Bob Grieb

Hi Steve,

   Once you get your scope going, I would check the reset to the CPU, and also the
main clock input.   Also make sure that the power rails to the CPU and nearby chips
look good.  I usually check the chip select to the first EPROM (which may not be the
active one, but you can hunt around and try to find one that is getting hit).   Then look
at the data bus bits to the EPROM and RAM chips to see if one is stuck high or low.
I worked on a Polaris recently that had a bad microprocessor chip.  One of the signals coming out of the chip was sitting at an intermediate level, instead of switching high and low.   Luckily the owner of the Polaris had a spare board that we could take another CPU from.  Another thing to try is removing the CPU from its socket and then putting it back.  You could also wipe the socket contacts off with a Qtip and some IPA, but that may not be nec.  You would want to handle the CPU very carefully to avoid ESD damage to it.   Ideally you would not touch any of the pins, just the package, which usually means using tweezers to grab it.  Same idea as unplugging and plugging cables and socketed chips to clean the contacts off.  Maybe better to leave the CPU alone until you have reason to suspect it.

    Good luck with your troubleshooting.

             Bob


From: merolasteve <no_reply@yahoogroups.com>
To: chromapolaris@yahoogroups.com
Sent: Tuesday, April 22, 2014 12:37 PM
Subject: [chromapolaris] Re: Chroma Polaris Lights up, but makes no sound.



Just to follow-up.  I re-seated just about every cable.  I still need to re-seat the cables that connect to the panel PCBs.  I VERY carefully reseated the 2 flat foil cables on the right.  I might try and do the wire repair to the cracked far right cable while I save up some cash for new membranes.  So far the biggest mistake I made was not removing the batteries while reseating the RAM chips.  According to Paul it may or may not have damaged them.  No changes to the current problem is visible though.

My main problem seems to be that the computer has crashed.

I contacted Paul off list and asked a few questions while inquiring about the membranes.  I wanted to post some of it here so that in the future newbs like myself can see it when they buy non-working boards.  However, I am in this to learn as much as possible.  A lot of it comes from the Service Manual.

Things to test first:

-re-seat all cables
-re-seat chips, without the batteries installed and after caps are drained (I read this elsewhere)
-measure output voltages: +5V REF and + 5 DIG are adjustable and should be adjusted within about 1%; +12V ANA, -12V ANA, -5V should be within 5%
-measure AC OK (about 5V) and DC OK (at least 2.5V)
-for the above tests all cables should be connected and power should be on; for a ground connection, attach meter to ground lug sticking up near where the power cables plug into the main board.
-measure power supply ripple at 60Hz and 120Hz using a scope to see if there is significant ripple...I'm still learning about this one.
-refer to schematics for other locations to test power supply voltages

I have been too busy with my home-remodeling to do most of this, but will hopefuly get to it soon.  I ordered some leads for my scope and some DN5 DeOxit.