Discussion about the Korg PolySix synthesizer

i had similar problems (i think #4 and D always on), but it still
worked okay for a year or so. then another problem appeared - the SUB
begun getting stuck and some problems with effects as well AFAIK. it
was really frustrating. at that point (after 4 or 5 repairs, i can't
remember) i have replaced both IC30, IC31, as well the main CPU (the
big 40-pin one near the resistor array) and repaired quite a lot of
traces. haven't scrapped them completely off though.

so else could i have done? i opened her up, took the board out, and
slowly started removing ALL the traces that looked even remotely
damaged. that means at some point, i had every single trace touching
IC30 and IC31 removed. quite a painful view. i also replaced the
resistor array. ALL the vias. i did just like in old crow's howto -
take an exacto and dig into the pcb, then try to get the trace to peel
off.

then i rewired it all, replaced the two ICs again, and - it works flawlessly.

jure

On Dec 27, 2007 5:17 AM, steven pistrich <wasteking1@yahoo.com> wrote:
> yes, very frustrating...
> My polysix has similarly #6, D and write on all the time and it has new IC 30 and 31...I cant figure where the continuity happens      unless, as i have heard , The pc board itself has conductivity  from the battery leakage..?  I found that scraping the traces away didnt solve the constantly on LED problems.  There seems to just be ' stray continuity '  so these switches are always on.  I havent solved this problem yet. I wish i had info on what each pin of IC 30 and 31 did. and which connected to which  letter/number LED's.
>
>
>
> ----- Original Message ----
> From: gil_we <gil_we@yahoo.com>
> To: PolySix@yahoogroups.com
> Sent: Wednesday, December 26, 2007 7:28:06 PM
> Subject: [PolySix] Re: now Chorus always on, Sub 2 Oct doesn't play root....
>
> Urrrrrgggggg !
>
> This is driving me nutz !
>
> The chorus/Sub problem probably was related with bad contact of the
> panel connectors. This is OK now, but when I checked the instrument
> again, if worked well for a few minute, and just than started to make
> some noise as tweaking the knobs, and the programs section now
> sometimes doesn't let you get banks B, 2 and 6, and will lite up the
> Manual button led when pushing the "Write" button.
>
> I can see on the schematics that the Write, B, 2 and 6 buttons are
> all connected to IC30 eventually, but it was already replaced, and
> has no bad traces going from it.
>
> --- In PolySix@yahoogroups .com, "gil_we" <gil_we@...> wrote:
> >
> > It looks a few problems still remain -
> >
> > I just noticed that whatever setting you use, the Chorus effect is
> > always working (very interesting sounding when using the Phaser or
> > Ensemble, which play with the Chorus.....). Also, when I use the Oct
> 2
> > setting (on Sub Osc), the root sound doesn't play.
> >
> > Can you think of any direction ? I suspected IC34 and IC29, but no
> > harm to them and no corrosion at all at this area....
> >
> > Thanks !
> >
> >
> >
> > --- In PolySix@yahoogroups .com, "gil_we" <gil_we@> wrote:
> > >
> > > Sure. As I said, IC30 was the culprit.
> > >
> > >
> > > --- In PolySix@yahoogroups .com, "muffclone" <muffclone@> wrote:
> > > >
> > > > -HELLO
> > > > THIS PROBLEM IS THE BAD TRACES OF IC30 AND IC31 (TWO 74LS08)
> AND
> > > REPLACE THIS
> > > > IC´S
> > > > AND THE VIAS OF THE BOARD CAN BE BAD.
> > > > SORRY FOR MY ENGLISH.....
> > > > MERRY CHRISTMAS!!
> > > > -- In PolySix@yahoogroups .com, "gil_we" <gil_we@> wrote:
> > > > >
> > > > > I have a nice looking P6 here. Battery has leaked and
> severely
> > > damaged
> > > > > the 74L08 near it and all traces beneath. The symptoms where
> > > > > non-functioning Release and VCO '16 Oct functions, and cases
> > > where a
> > > > > few preset leds light up together including the Write button
> led
> > > which
> > > > > will sometimes light on and will not turn off. Also, pitch
> and
> > > cutoff
> > > > > can change spontaneously as you play some chords.
> > > > >
> > > > > I had it retraced and cleaned of course, and replaced the
> 74LS08
> > > and
> > > > > 4011 above the battery (although the latter looked ok).
> > > > >
> > > > > The current situation is that the Release and VCO '16 Oct
> > > functions
> > > > > work ok, but the mess with the bank preset leds still exists.
> Can
> > > you
> > > > > spot a particular IC which can cause the problem ? Other
> ideas ?
> > > > >
> > > >
> > >
> >
>
>
>
>
>
>       ____________________________________________________________________________________
> Looking for last minute shopping deals?
> Find them fast with Yahoo! Search.  http://tools.search.yahoo.com/newsearch/category.php?category=shopping
>
> [Non-text portions of this message have been removed]
>
>
>
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
>
>
>
>