Rhodes Chroma Polaris

> From: Conor Strachan [mailto:conor.strachan@...] 
> 
> I am having a few issues with my Polaris, it has the new 
> membrane panels and was working fine for over a year and then 
> all of a sudden it started to play up.
> 
> It is turning on and then after about 10 seconds the panel is 
> freezing along with the notes sustaining or gliding then sustaining.
> 
> I am consulting the service manual but there is a lot of 
> reference to the older secondary power board and I have the 
> later one so it is a little confusing.
> 
> I have checked my DC OK which I believe should be +5v (brown 
> wire P3) but it goes to about +4.75v when it is first turned 
> on with panel access then it fluctuates up to 4.80v and it 
> stays around the +4.80v mark where the panel is frozen.
> 
> According to the manual it says there is no way to adjust 
> anything on the DCOK side on the later boards. 
> 
> Just wondering if you have any suggestions of where to go next..

Does it ever unfreeze spontaineously, or do you have to cycle the power to get it going again?

I doubt it's a DCOK problem. You should check all the power supply voltages. If you have access to a scope, you should also make sure that the supplies have no significant power line ripple on them. That can happen when the big caps on the power supply dry out.

It's also possible that the EPROMs are fading. That can be fixed by erasing them and reprogramming them with the files available on the rhodeschroma.com site. If you don't have a programmer, and can't find someone nearby who does, they're available on eBay for about $50.

I've cc-ed this to the mailing list, so that others can put in their two cents.

-- 

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

Hello All,
I too have a Polaris which I’ve added new membrane panel to.
Initially it was all frozen, gradually by power cycling (and getting to the tune function etc) it will go a few minutes before crashing in the same manner as described by Conor.
All my voltages appear good. So Paul do you suggest psu ripple or faded EPROMs as probable causes?
I calibrated my DAC (dc offset) which made it better but the machine still crashes without fail. I thought I would chime in here as it might be a common issue caused by ??
Thanks!

Sent from my iPhone

> On 13 Jul 2018, at 12:15, 'Paul D. DeRocco' pderocco@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:
> 
> > From: Conor Strachan [mailto:conor.strachan@...] 
> > 
> > I am having a few issues with my Polaris, it has the new 
> > membrane panels and was working fine for over a year and then 
> > all of a sudden it started to play up.
> > 
> > It is turning on and then after about 10 seconds the panel is 
> > freezing along with the notes sustaining or gliding then sustaining.
> > 
> > I am consulting the service manual but there is a lot of 
> > reference to the older secondary power board and I have the 
> > later one so it is a little confusing.
> > 
> > I have checked my DC OK which I believe should be +5v (brown 
> > wire P3) but it goes to about +4.75v when it is first turned 
> > on with panel access then it fluctuates up to 4.80v and it 
> > stays around the +4.80v mark where the panel is frozen.
> > 
> > According to the manual it says there is no way to adjust 
> > anything on the DCOK side on the later boards. 
> > 
> > Just wondering if you have any suggestions of where to go next..
> 
> Does it ever unfreeze spontaineously, or do you have to cycle the power to get it going again?
> 
> I doubt it's a DCOK problem. You should check all the power supply voltages. If you have access to a scope, you should also make sure that the supplies have no significant power line ripple on them. That can happen when the big caps on the power supply dry out.
> 
> It's also possible that the EPROMs are fading. That can be fixed by erasing them and reprogramming them with the files available on the rhodeschroma.com site. If you don't have a programmer, and can't find someone nearby who does, they're available on eBay for about $50.
> 
> I've cc-ed this to the mailing list, so that others can put in their two cents.
> 
> -- 
> 
> Ciao, Paul D. DeRocco
> Paul mailto:pderocco@...
> 
>

I had the same freezing problem after installing the new membrane.  Found out that the tails on the right side drooped too low and were touching the Output board.  After I tucked them up under the right side panel, no more problems.  No more freeze ups and she's singing like a birdie.  In my case, (no pun) the tails and the board may have been too close.  Could be slightly different specs on the top and the case for different synths.  Who knows.  Nobody here seems to want to answer me about this.

Tracy




--------------------------------------------
On Thu, 7/12/18, taco taco tacosaresoawesome@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:

 Subject: Re: [chromapolaris] RE: Polaris Later version Secondary board
 To: chromapolaris@yahoogroups.com
 Date: Thursday, July 12, 2018, 11:21 PM
 
 
  
 
 
 
   
 
 
     
       
       
       Hello All,I too have a Polaris which
 I’ve added new membrane panel to.Initially it
 was all frozen, gradually by power cycling (and getting to
 the tune function etc) it will go a few minutes before
 crashing in the same manner as described by
 Conor.All my voltages appear good. So Paul do you
 suggest psu ripple or faded EPROMs as probable
 causes?I calibrated my DAC (dc offset) which made
 it better but the machine still crashes without fail. I
 thought I would chime in here as it might be a common issue
 caused by ??Thanks!
 
 Sent
 from my iPhone
 On 13 Jul 2018, at
 12:15, 'Paul D. DeRocco' pderocco@...om.com
 [chromapolaris] <chromapolaris@yahoogroups.com>
 wrote:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
  
 
 
 
     
       
       
       > From: Conor Strachan [mailto:conor.strachan@...]
 
 
 > 
 
 > I am having a few issues with my Polaris, it has the
 new 
 
 > membrane panels and was working fine for over a year
 and then 
 
 > all of a sudden it started to play up.
 
 > 
 
 > It is turning on and then after about 10 seconds the
 panel is 
 
 > freezing along with the notes sustaining or gliding
 then sustaining.
 
 > 
 
 > I am consulting the service manual but there is a lot
 of 
 
 > reference to the older secondary power board and I have
 the 
 
 > later one so it is a little confusing.
 
 > 
 
 > I have checked my DC OK which I believe should be +5v
 (brown 
 
 > wire P3) but it goes to about +4.75v when it is first
 turned 
 
 > on with panel access then it fluctuates up to 4.80v and
 it 
 
 > stays around the +4.80v mark where the panel is
 frozen.
 
 > 
 
 > According to the manual it says there is no way to
 adjust 
 
 > anything on the DCOK side on the later boards. 
 
 > 
 
 > Just wondering if you have any suggestions of where to
 go next..
 
 
 
 Does it ever unfreeze spontaineously, or do you have to
 cycle the power to get it going again?
 
 
 
 I doubt it's a DCOK problem. You should check all the
 power supply voltages.. If you have access to a scope, you
 should also make sure that the supplies have no significant
 power line ripple on them. That can happen when the big caps
 on the power supply dry out.
 
 
 
 It's also possible that the EPROMs are fading. That can
 be fixed by erasing them and reprogramming them with the
 files available on the rhodeschroma.com site. If
 you don't have a programmer, and can't find someone
 nearby who does, they're available on eBay for about
 $50.
 
 
 
 I've cc-ed this to the mailing list, so that others can
 put in their two cents.
 
 
 
 -- 
 
 
 
 Ciao,               Paul D. DeRocco
 
 Paul                mailto:pderocco@...
 
 
 
 
 
     
      
 
     
 
 
 
 
 
 
 
 
 
     
      
 
     
     
 
 
 
 #yiv3306785335 #yiv3306785335 --

I did forget to say my voltages were in range as well on the ribbon cables, amongst other things.  But, I'm not a tech - just a lowly newbie.  :)

Tracy
--------------------------------------------
On Thu, 7/12/18, taco taco tacosaresoawesome@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:

 Subject: Re: [chromapolaris] RE: Polaris Later version Secondary board
 To: chromapolaris@yahoogroups.com
 Date: Thursday, July 12, 2018, 11:21 PM
 
 
  
 
 
 
   
 
 
     
       
       
       Hello All,I too have a Polaris which
 I’ve added new membrane panel to.Initially it
 was all frozen, gradually by power cycling (and getting to
 the tune function etc) it will go a few minutes before
 crashing in the same manner as described by
 Conor.All my voltages appear good. So Paul do you
 suggest psu ripple or faded EPROMs as probable
 causes?I calibrated my DAC (dc offset) which made
 it better but the machine still crashes without fail. I
 thought I would chime in here as it might be a common issue
 caused by ??Thanks!
 
 Sent
 from my iPhone
 On 13 Jul 2018, at
 12:15, 'Paul D. DeRocco' pderocco@...
 [chromapolaris] <chromapolaris@yahoogroups.com>
 wrote:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
  
 
 
 
     
       
       
       > From: Conor Strachan [mailto:conor.strachan@...]
 
 
 > 
 
 > I am having a few issues with my Polaris, it has the
 new 
 
 > membrane panels and was working fine for over a year
 and then 
 
 > all of a sudden it started to play up.
 
 > 
 
 > It is turning on and then after about 10 seconds the
 panel is 
 
 > freezing along with the notes sustaining or gliding
 then sustaining.
 
 > 
 
 > I am consulting the service manual but there is a lot
 of 
 
 > reference to the older secondary power board and I have
 the 
 
 > later one so it is a little confusing.
 
 > 
 
 > I have checked my DC OK which I believe should be +5v
 (brown 
 
 > wire P3) but it goes to about +4.75v when it is first
 turned 
 
 > on with panel access then it fluctuates up to 4.80v and
 it 
 
 > stays around the +4.80v mark where the panel is
 frozen.
 
 > 
 
 > According to the manual it says there is no way to
 adjust 
 
 > anything on the DCOK side on the later boards. 
 
 > 
 
 > Just wondering if you have any suggestions of where to
 go next..
 
 
 
 Does it ever unfreeze spontaineously, or do you have to
 cycle the power to get it going again?
 
 
 
 I doubt it's a DCOK problem. You should check all the
 power supply voltages.. If you have access to a scope, you
 should also make sure that the supplies have no significant
 power line ripple on them. That can happen when the big caps
 on the power supply dry out.
 
 
 
 It's also possible that the EPROMs are fading. That can
 be fixed by erasing them and reprogramming them with the
 files available on the rhodeschroma.com site. If
 you don't have a programmer, and can't find someone
 nearby who does, they're available on eBay for about
 $50.
 
 
 
 I've cc-ed this to the mailing list, so that others can
 put in their two cents.
 
 
 
 -- 
 
 
 
 Ciao,               Paul D. DeRocco
 
 Paul                mailto:pderocco@...
 
 
 
 
 
     
      
 
     
 
 
 
 
 
 
 
 
 
     
      
 
     
     
 
 
 
 #yiv0907306828 #yiv0907306828 --

> From: Tracy
> 
> I had the same freezing problem after installing the new 
> membrane.  Found out that the tails on the right side drooped 
> too low and were touching the Output board.  After I tucked 
> them up under the right side panel, no more problems.  No 
> more freeze ups and she's singing like a birdie.  In my case, 
> (no pun) the tails and the board may have been too close.  
> Could be slightly different specs on the top and the case for 
> different synths.  Who knows.  Nobody here seems to want to 
> answer me about this.

That's because none of us knows the answer. ;-)

Your observation of the tails touching the output board is something that I never noticed. On the other hand, I never had a problem with it. I can't see what's going on when the unit is closed, but it would have to be bending substantially around the edge of the board (which has no metal) in order to contact the lead of some component mounted near the edge of the board.

The newest batch of panels have the insulation on the tails cut back. I did that so that if the ends of the tails are ever damaged, they can be shortened. Perhaps that's why no one had a problem before. That's probably why it's now an issue. It's probably a good idea to tuck them under, or put a piece of tape along the top edge of the output board. Or just cut them shorter, although then you lose the ability to cut them in the future if they're ever damaged.

-- 

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

> From: chromapolaris@yahoogroups.com 
> 
> Well I've got it all out on a bench so no membrane tail contact..
> 
> What happens is it powers on is responsive like normal for 5 
> seconds then it starts going a bit crazy doing random things 
> then it just freezes. If I turn it off and back on straight 
> away it is still frozen but if you leave it for a minute you 
> can repeat the whole thing again until it freezes. There is 
> some nasty crackling happening on the output like some 
> electricity bacon sizzling on a pan..
> 
> I have the later secondary power board so it is a bit 
> difficult as the service manual is really written for the first board.
> 
> I am getting 4.80v on the DCOK when frozen.. but right away 
> it is 4.76v with responsiveness before freeze.
> 
> Digi +5 it is hard to get it to load up with the Lower 
> function D 3 but when I can all lights are lit and I am 
> getting +4.83V (now in the manual it says to adjust R9 but 
> there is no R9 to adjust on the secondary board>?? I need to 
> get this up to 5v?)
> 
> Ref +5v - this is at +4.98v
> 
> AC OK - 4.69v (measuring this from P3 4 yellow wire to the 
> ground in middle of main board.)
> 
> On the -12v I am getting -12.30V
> On the +12v I am getting +12.08V

If it works for a while, then quits and never comes back, I would suspect the following sorts of things:

* Fading EPROMs, which occasionally drop a bit. This would be my first choice, because I have a programmer and eraser, and it only takes fifteen minutes to erase the EPROMs and reprogram them.

* Bad ripple on the digital 5V supply, due to a dried out C3 in the power supply.

* A floating input on a CMOS chip, or the CPU, perhaps due to crud in a socket, allowing the voltage on that pin to drift around. That's the hardest thing to find.

The voltages you're measuring look okay. You could try goosing the digital 5V to see if that helps--it's R3 on the newer board. The schematic package from rhodeschroma.com includes both versions.

-- 

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

> From: conor.strachan@...
> 
> The amount of noise coming of the output with the crackling 
> It doesn't make me think it's a power thing coming from somewhere. 
> 
> Do you mean the VR at R4 on the secondary board. On my board 
> the R3 is not tweakable it's only R4 and R15 that have trimmers. 

Yes, it's R4. I misread the schematic.

> First thing I will do after that is change the caps, as it's 
> easy to do and start with the one that looks a bit corroded for sure. 

Sounds good.

> A friend of mine was saying it might be the Z2 5v regulator 
> as he said it's happen to him on few synths before but I 
> believe on the board it is a 12v regulator and not a 5v there 
> is a LM340 on the schemes but inside mine at Z2 is a LM7812ct 
> which I believe is 12v. That might be worth a try if the caps 
> are not the problem. 

I'm sure the regulators are okay, or they'd be putting out a much higher voltage or zero.

> I would need to get hold of an EPROM programmer to redo them 
> which I can do, but this just happened pretty much overnight 
> so it wasn't like it was a slow decrease in functionality..

Well, all it takes is one bit to finally drift across the threshold, turning one machine instruction into another one and causing a crash.

> I could clean out the RAM and processor sockets, i can't see 
> how to get the metal shield off that processed though. 

You slide it to the right. It's very snug. If you want to remove the RAMs, you'll have to unplug the battery first, and then redo all the calibrations when it's all back together.

-- 

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

I should have said when the cover was on.  My mistake.

Tracy



--------------------------------------------
On Fri, 7/13/18, conor.strachan@...m [chromapolaris] <chromapolaris@yahoogroups.com> wrote:

 Subject: Re: [chromapolaris] RE: Polaris Later version Secondary board
 To: chromapolaris@yahoogroups.com
 Date: Friday, July 13, 2018, 9:46 AM
 
 
  
 
 
 
   
 
 
     
       
       
       Hi there
 Well
 I've got it all out on a bench so no membrane tail
 contact..
 What happens
 is it powers on is responsive like normal for 5 seconds then
 it starts going a bit crazy doing random things then it just
 freezes. If I turn it off and back on straight away it is
 still frozen but if you leave it for a minute you can repeat
 the whole thing again until it freezes. There is some nasty
 crackling happening on the output like some electricity
 bacon sizzling on a pan..
 I have the later secondary power
 board so it is a bit difficult as the service manual is
 really written for the first board.
 I am getting 4.80v on the DCOK when
 frozen.. but right away it is 4.76v with responsiveness
 before freeze.
 Digi +5
 it is hard to get it to load up with the Lower function D 3
 but when I can all lights are lit and I am getting +4.83V
 (now in the manual it says to adjust R9 but there is no R9
 to adjust on the secondary board>?? I need to get this up
 to 5v?)
 Ref +5v - this
 is at +4.98v
 AC OK -
 4.69v (measuring this from P3 4 yellow wire to the ground in
 middle of main board.)
 On the -12v I am getting
 -12.30VOn the +12v I am getting
 +12.08V
 If anyone has
 any suggestions let me know. I don't have a scope at
 hand just a multimeter..
 Cheers
 Conor
 
     
      
 
     
     
 
 
 
 #yiv3499830465 #yiv3499830465 --

They tuck under just fine.  As long as you don't man-handle them.  The only conclusion I can come up with is when they were looped out, they must've touched the board.  Tucked under the panel there's no problem.  Or, as we used to say back in the IBM PC days, it's cosmic rays for all the problems.  Now they've proven it!  LOL!

Tracy

--------------------------------------------
On Fri, 7/13/18, 'Paul D. DeRocco' pderocco@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:

 Subject: RE: [chromapolaris] RE: Polaris Later version Secondary board
 To: chromapolaris@yahoogroups.com
 Date: Friday, July 13, 2018, 3:10 PM
 
 
  
 
 
 
   
 
 
     
       
       
       > From: Tracy
 
 > 
 
 > I had the same freezing problem after installing the
 new 
 
 > membrane.  Found out that the tails on the right side
 drooped 
 
 > too low and were touching the Output board.  After I
 tucked 
 
 > them up under the right side panel, no more problems. 
 No 
 
 > more freeze ups and she's singing like a birdie. 
 In my case, 
 
 > (no pun) the tails and the board may have been too
 close.  
 
 > Could be slightly different specs on the top and the
 case for 
 
 > different synths.  Who knows.  Nobody here seems to
 want to 
 
 > answer me about this.
 
 
 
 That's because none of us knows the answer. ;-)
 
 
 
 Your observation of the tails touching the output board is
 something that I never noticed. On the other hand, I never
 had a problem with it. I can't see what's going on
 when the unit is closed, but it would have to be bending
 substantially around the edge of the board (which has no
 metal) in order to contact the lead of some component
 mounted near the edge of the board.
 
 
 
 The newest batch of panels have the insulation on the tails
 cut back. I did that so that if the ends of the tails are
 ever damaged, they can be shortened. Perhaps that's why
 no one had a problem before. That's probably why
 it's now an issue. It's probably a good idea to tuck
 them under, or put a piece of tape along the top edge of the
 output board. Or just cut them shorter, although then you
 lose the ability to cut them in the future if they're
 ever damaged.

The CPU cover slides to the left and then up.

Tracy


--------------------------------------------
On Fri, 7/13/18, conor.strachan@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:

 Subject: [chromapolaris] RE: Polaris Later version Secondary board
 To: chromapolaris@yahoogroups.com
 Date: Friday, July 13, 2018, 4:01 PM
 
 
  
 
 
 
   
 
 
     
       
       
       Hi Paul 
 
 
 
 Thanks for your reply.
 
 The amount of noise coming of the output with the crackling
 It doesn't make me think it's a power thing coming
 from somewhere. 
 
 
 
 Do you mean the VR at R4 on the secondary board. On my board
 the R3 is not tweakable it's only R4 and R15 that have
 trimmers. 
 
 
 
 First thing I will do after that is change the caps, as
 it's easy to do and start with the one that looks a bit
 corroded for sure. 
 
 
 
 A friend of mine was saying it might be the Z2 5v regulator
 as he said it's happen to him on few synths before but I
 believe on the board it is a 12v regulator and not a 5v
 there is a LM340 on the schemes but inside mine at Z2 is a
 LM7812ct which I believe is 12v. That might be worth a try
 if the caps are not the problem. 
 
 
 
 I would need to get hold of an EPROM programmer to redo them
 which I can do, but this just happened pretty much overnight
 so it wasn't like it was a slow decrease in
 functionality..
 
 
 
 I could clean out the RAM and processor sockets, i can't
 see how to get the metal shield off that processed though.
 
 
 
 
 Thanks for your help Polaris People 
 
     
      
 
     
     
 
 
 
 #yiv9781839065 #yiv9781839065 --

> From: Tracy
> 
> The CPU cover slides to the left and then up.

I guess there are two different sockets. The one I've got goes the other way. But it is a matter of sliding the cover.

-- 

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

Yup.

Just take it slow because it could be easy to bust a pin below the container.  Not only that, they can get stubborn and hard to slide.  But, if you take your time, it works fine.  No way to put the chip back in wrong because of the corners.

Was it a bad thing to put some Arctic Silver on top of the CPU, which would be under the lid?  My thought was to cool it down some.  The power supply "heat" decreased after I did that and it ran a little cooler.  Just a PC repair topic that works and for many CPUs, cuts the heat 10 - 20 degrees.  Yell at me if I did a faux pas.

I want my Polaris to run for another n years if I can.  It's a funky synth to play with.

Tracy


--------------------------------------------
On Sun, 7/15/18, 'Paul D. DeRocco' pderocco@... [chromapolaris] <chromapolaris@...m> wrote:

 Subject: RE: [chromapolaris] RE: Polaris Later version Secondary board
 To: chromapolaris@yahoogroups.com
 Date: Sunday, July 15, 2018, 1:48 PM
 
 
  
 
 
 
   
 
 
     
       
       
       > From: Tracy
 
 > 
 
 > The CPU cover slides to the left and then up.
 
 
 
 I guess there are two different sockets. The one I've
 got goes the other way. But it is a matter of sliding the
 cover.
 
 
 
 -- 
 
 
 
 Ciao,               Paul D. DeRocco
 
 Paul                mailto:pderocco@...
 
 
 
 
 
     
      
 
     
     
 
 
 
 #yiv2996453372 #yiv2996453372 --

> From: Tracy
> 
> Just take it slow because it could be easy to bust a pin 
> below the container.  Not only that, they can get stubborn 
> and hard to slide.  But, if you take your time, it works 
> fine.  No way to put the chip back in wrong because of the corners.
> 
> Was it a bad thing to put some Arctic Silver on top of the 
> CPU, which would be under the lid?  My thought was to cool it 
> down some.  The power supply "heat" decreased after I did 
> that and it ran a little cooler.  Just a PC repair topic that 
> works and for many CPUs, cuts the heat 10 - 20 degrees.  Yell 
> at me if I did a faux pas.

It probably does reduce the temperature, but I don't think we ever had any problems caused by the hot CPU. They're rated for 70C, or 158F, which is pretty toasty. If you really want to cool it, you could attach a finned heat sink to the socket cover. They make ones that have adhesive backings.

-- 

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

Right.

These were the "early" days of CPU of any power at all. IBM PC was 4.77 MHz and the Polaris had an 80186, yes?

I figured it wouldn't hurt it any considering I'm using good stuff on it.  Cooled the power supply also.  Since I was pulling ALL of the chips ans spraying them lightly with canned air, I'd do a total job.



--------------------------------------------
On Mon, 7/16/18, 'Paul D. DeRocco' pderocco@... [chromapolaris] <chromapolaris@yahoogroups.com> wrote:

 Subject: RE: [chromapolaris] RE: Polaris Later version Secondary board
 To: chromapolaris@yahoogroups.com
 Date: Monday, July 16, 2018, 11:29 PM
 
 
  
 
 
 
   
 
 
     
       
       
       > From: Tracy
 
 > 
 
 > Just take it slow because it could be easy to bust a
 pin 
 
 > below the container.  Not only that, they can get
 stubborn 
 
 > and hard to slide.  But, if you take your time, it
 works 
 
 > fine.  No way to put the chip back in wrong because of
 the corners.
 
 > 
 
 > Was it a bad thing to put some Arctic Silver on top of
 the 
 
 > CPU, which would be under the lid?  My thought was to
 cool it 
 
 > down some.  The power supply "heat" decreased
 after I did 
 
 > that and it ran a little cooler.  Just a PC repair
 topic that 
 
 > works and for many CPUs, cuts the heat 10 - 20 degrees.
  Yell 
 
 > at me if I did a faux pas.
 
 
 
 It probably does reduce the temperature, but I don't
 think we ever had any problems caused by the hot CPU.
 They're rated for 70C, or 158F, which is pretty toasty.
 If you really want to cool it, you could attach a finned
 heat sink to the socket cover. They make ones that have
 adhesive backings.
 
 
 
 -- 
 
 
 
 Ciao,               Paul D. DeRocco
 
 Paul                mailto:pderocco@...

> From: conor.strachan@...
> 
> I recapped and I am no longer getting freezes but I think I 
> have finally isolated the actual problem, the synth is not 
> freezing and is operating fine unless the audio cable is 
> plugged into the either mono audio outs or phones jack, when 
> I do this it will freeze pretty much straight away or after 
> two or three seconds. 
> 
> The moment I put the audio cable in it freezes, signal is 
> giving a buzz. I think I am shorting the whole synth when the 
> audio cable is inserted. Now it looks like someone has 
> previously done something funky to jacks. My phones jack had 
> broken away from the chasis so I just took it off and will 
> replace it. If anyone has any clues from looking at the 
> wiring of what it could be thats shorting it out. There are a 
> couple of resistors bridging on the mono outputs. The brown 
> wire has tape around it and has been put out of use. The 
> black ground is going to the headphones along with a yellow 
> that is bridged across by a piece of metal.
> 
> Was anyone aware of this mod? something might of gone wrong 
> with mine..

The factory modified the design at some point. Originally, the brown wire was intended to be used as the ground on the headphone jack. They changed that, and ran a wire from the headphone jack ground back all the way back to the power supply. I've always found that that made the output really noisy. It works better to remove that wire (it looks like it's black in your pictures--mine were green), then pull the shrink tubing off the brown wire and use that to ground the headphones. The only downside is that if you use headphones at the same time you use the line output, you may get some clipping in the line output.

That said, I don't know how the current grounding scheme would cause your problem, or how the alternative would fix it, unless there's a missing or broken ground connection somewhere else. I would poke around with a meter, looking for voltages between various ground points. How much voltage do you see between the grounds on the headphone jack and the jack next to it? How about between some ground on the main board and a ground up on the panel boards?

-- 

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

> …  the synth is not freezing and is operating fine unless the audio cable is plugged 
> into the either mono audio outs or phones jack, when I do this it will freeze pretty 
> much straight away or after two or three seconds. 
>… The moment I put the audio cable in it freezes, signal is giving a buzz...

In addition to Paul's reply, a couple quick practical tests should help to focus where to look/what to look at.

1) install a cable into the Polaris' connector but _do not_ connect the other end of that cable anywhere - and evaluate how/if it fails.

2) instead of a non-connected cable, install a pair of headphones into the line jack - and evaluate how/if it fails.

If the same failure occurs with #1 - then the implication is that you're looking for an electrical connection which is being made just by the presence of the jack (e.g., switches on the jack).

If the failure does not occur on #1 but does occur on #2, then the implication is the behaviour involves a connection between ground and signal.

If the failure does not occur on #1 or #2, but does occur when the 1/4" cable is attached between the Polaris and to some other piece of equipment (e.g., mixer, amp, etc.) then the implication is a ground loop being formed between the Polaris and the external piece of equipment.

Note - to give this test more meaning, it is recommended to disconnect all other connections from the Polaris during these tests, including any MIDI, cassette or pedal connections.  (This will help ensure that any 'connections' being tested are only ones from the 1/4" jacks - and not be influenced by items such as a ground mis-match between what is on one end of MIDI and what is on the other end of that cable).