Discussion about the Korg PolySix synthesizer

don't get too excited but there could be another explanation:

the last (and like 3rd) time i decided to repair my polysix i found
something really funny. i completely removed like 20 traces and
rewired everything back up, replaced IC30 and IC31 and also replaced
the main CPU (ic40 i think). just so i could be sure that this time is
the last time i have her open. i also removed the pattern/bank keys
frontpanel and checked some connections there. and then i assembled
the whole thing back... and the pattern 3 + bank D were lit when i
turned the synth on. and the arp light also.

then it took me a few more hours to find out that the key panels were
screwed too tightly, so a few keys were pressed constantly. seriously.
mine works flawlessly now.

cheers,
jure

On Nov 19, 2007 5:34 AM, klosmon <klosmon@sbcglobal.net> wrote:
> It sounds like you've reached the point where a scope is necessary
> for any meaningful work -- this will help you zero in on the problem
> areas, and is a much better idea than just replacing ICs at random.
> (The Polysix circuit boards aren't that robust to begin with;  they
> don't stand up to too much desoldering & resoldering.  Add to that
> the weakening caused by battery damage, and it becomes obvious that
> random replacing of components may not work out so well.)
>
> If you can borrow an oscilloscope, view the outputs of IC31 (pins 3,
> 6, 8 and 11) -- should see strong, consistent signals.  Look for the
> same on IC30 (same pin numbers) -- these two ICs distribute the data
> lines DO0 - DO7 to all the circuitry.  Look at the connectors CN06
> and CN10 -- see if all "D" and "P" signals are present.  If they're
> not, this could be the cause of your problem.
>
> As stated before, there isn't just one IC that controls the panel --
> it's a matrix of data lines that work together to control a number of things.
>
> Another thought:  have you checked the wires that are soldered to the
> front panel, right side?
>
> ~G
> At 08:01 PM 11/18/2007, you wrote:
>
> >well, i replaced all the bad traces, put in a socket for the IC31
> >and a new IC31 that had never been heated/soldered into the socket,
> >established all continuities, and my problem is still
> >there....The 'write' LED and the LED's for program #4and 6 and D
> >stay lit. i can also switch between #1,2,3, but i get no response
> >above #4....Does anyone have an idea if another chip is at fault that
> >controls these LED's? if its not IC31? --- In
> ><mailto:PolySix%40yahoogroups.com>PolySix@yahoogroups.com, klosmon
> ><klosmon@...> wrote:
> > >
> > > At 01:05 PM 11/14/2007, you wrote:
> > >
> > > >My thoughts exactly, ive already ordered the IC AND a socket... (
> > > >parts cost under $2) that way i dont have to heat the IC at
> > > >all....But I still wonder what the IC 31 does, and if it controls
> > > >the patch selection, etc.
> > >
> > >
> > > Well, I answered that question a few days ago -- see message #1692.
> > > That answer contains good and true information, based on having
> > > repaired about forty polysixes. Not sure what I could add...
> > > ~G
> > >
> > >
> > >
> > > --
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>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
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