Discussion about the Korg PolySix synthesizer

Hey, any news ?




--- In PolySix@yahoogroups.com, Niels Ott <niels.ott@...> wrote:
>
> Hi gil,
> 
> the SSM* are OK, I checked them. I had a nice day with the 
oscilloscope
> and found out: The output of the signal generator board is already 
bad.
> 
> Then I replaced two opamps 4558 which I suspected to be the problem 
but
> it didn't help. Still 0V out instead if the signal on oszillator 2 
(VCO
> 1 (sic)).
> 
> Next suspect was the CMOS switch which I replaced by a similar 
type. But
> Somehow it wasn't similar enough, so I got -9V in the output now, 
which
> is definitely not good.
> 
> I'll keep on soldering. ;-)
> 
> Best,
> 
>    Niels
> 
> 
> gil_we schrieb:
> > Did you switch SSM2056 and SSM2044 between voices to see if it 
may 
> > lay there ?
> > 
> > 
> > --- In PolySix@yahoogroups.com, Niels Ott <niels.ott@> wrote:
> >> Hello there,
> >>
> >> my Trident MK2 is defective.
> >>
> >> Symptom: VCO 1 is defective for one voice.
> >>
> >> Up to now I was able to found out: Input 1 of IC704 (4x CMOS 
> > switch) on
> >> KLM-379 doesn't get the VCO signal on voice 7. On all others it 
> > does.
> >> There are some oddities with op amp IC707 but I'm not yet sure. 
The
> >> schematics and the circuit board design hint to the direction 
that 
> > IC707
> >> "feeds" IC704.
> >>
> >> The IC707 is a 4558, I assume that it is similar in the Polysix.
> >>
> >> Did anybody of you experience a similar problem? What about 
> > replacing
> >> the 4558, did this help?
> >>
> >> Furthermore, some of the 4558s carry a date stamp of 1997 which 
> > means
> >> they must have been replaced by an earlier owner.
> >>
> >> Unfortunately there is no shop selling electronic parts in reach 
so 
> > I
> >> can't just go for it and try replacing it. Mail order is an 
option 
> > but
> >> not for a few ICs...
> >>
> >> Thank you for commenting.
> >>
> >> Best,
> >>
> >>   Niels
> >>
> > 
> > 
> > 
> > 
> > 
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> > Yahoo! Groups Links
> > 
> > 
> > 
> >
>