Discussion about the Korg PolySix synthesizer

That's a nice meter. On the Rx1 scale you should easily be able to see if
any tracks are approaching 1 ohm, which is a sign they should be fixed. Just
make sure it's zeroed properly. I said digital meter because most analog
meters aren't very accurate on that low scale. If the previous owner said
this Polysix was working fine a few years ago, then I think his definition
of a "few" is different than mine. I would guess a decade or more.

Don B.

 

  _____  

From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
traxus12
Sent: Wednesday, August 07, 2013 4:25 PM
To: PolySix@yahoogroups.com
Subject: [PolySix] Re: Help! Repairing a Polysix with burst battery (sound
demo + photos!)

 

  

Thanks! I'll try that. Hopefully I can find the culprit. By the way, I'm
using a Simpson 260-8XI analog multimeter.

I just remembered that the previous owner mentioned it was working fine when
he got it from his school a few years ago and it had just been sitting in
his garage since then. So whatever went wrong happened within the last few
years, if that's any clue.

--- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ,
"backshall1" <backshall1@...> wrote:
>
> That board doesn't look too bad at all. Most look much worse after a
battery
> leak. Unfortunately that means there is no easy way to point to the
problem
> without some long and tedious debugging. You will need a digital
multimeter,
> not just something that goes "beep", and you will need the schematics. It
> sounds like a problem on the D0-D7 data bus coming off of IC30 and IC31
and
> you will need to check those traces again and actually measure the
> resistance. Any trace more than 0.5 ohms should probably be fixed. The
data
> bus connects many chips together and you will need to check between each
> chip, which is why you will need the schematics to see which pins on which
> chips should be connected. As mentioned by Andy Jury in several old posts,
a
> good way to do this is to check continuity from connector CN10 to each of
> these chips: IC 30, 31, 26, 24, 33, 28, 29, 34, 35 and CN06 on each of the
> eight bus lines. Like I said, tedious.
> 
> You will have to watch out for the mislabeled chip in the diagram. There
are
> two IC 34 in the diagram. The one beside IC 30 is actually IC 24.
> 
> 
> 
> Don Backshall
> 
> 
> 
> _____ 
> 
> From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
[mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ] On
Behalf Of
> traxus12
> Sent: Wednesday, August 07, 2013 5:02 AM
> To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> 
> Subject: [PolySix] Re: Help! Repairing a Polysix with burst battery (sound
> demo + photos!)
> 
> 
> 
> 
> 
> Sorry, some of my formatting didn't make it through to the final post. I
> meant to include these. 
> 
> sound demo:
> https://soundcloud.com/ocguitar/korg-polysix-death-sounds
> 
> Bank D and Program 4 constantly illuminated:
> http://imgur.com/TFEPUPB
> 
> Thank you! Any advice would be appreciated.
> -Steve
> 
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
<mailto:PolySix%40yahoogroups.com> ,
> "traxus12" <ocguitar@> wrote:
> >
> > Hello! I picked up a Korg Polysix recently and I've been trying to bring
> > it back to life. Nothing I've done has changed anything yet so I'm at a
> > bit of an impasse and I'm hoping someone out there might be able to help
> > me narrow down what I should do next. I know how to use a soldering iron
> > but I'm a complete beginner at repairing circuit board traces.
> > 
> > Let me give you the symptoms.
> > 
> > 1. It sounds like it's gone absolutely mental with constant oscillation
> > and other insanity going on from the moment I power it up.
> > 2. The Bank D and Program 4 buttons are constantly illuminated after
> > powering up.
> > 
> > After cleaning up most of the corrosion I could find around the battery,
> > it really didn't look as bad as I thought it might so I went ahead and
> > just installed a Lithium battery holder (using Old Crow's guide) and
> > tried powering up again. Nothing changed.
> > 
> > After that, I went back in and removed the IC31 chip (74LS08) and tested
> > all the traces in the area with a multimeter. Every trace I tested gave
> > me a happy little beep, even the uglier looking ones that were near the
> > old battery, so I went ahead and soldered in a new socket and 74LS08
> > chip at IC31. Powered up. Nothing changed.
> > 
> > Now, I'm not sure what to do. Did I miss a trace? Should I put jumper
> > wires on the ugly looking traces even if my multimeter says they're
> > conducting just fine? Should I replace the other ICs that were near the
> > battery like IC30 even if they look fine?
> > 
> > I recorded a sound demo. For the first 40 seconds I don't touch a thing,
> > then I start to experiment:
> > 
> > 
> > Bank D and Program 4 constantly illuminated:
> > 
> > 
> > First sight:
> > <http://imgur.com/Wv173WQ>
> > 
> > After initial cleanup:
> > <http://imgur.com/M8POlkz>
> > 
> > Installed battery:
> > <http://imgur.com/Pj3kDFT>
> > 
> > Replaced IC31:
> > <http://imgur.com/Nab9GYz>
> > 
> > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>





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