Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

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Subject: Re: Problems with parasitic LFO in VCA?

From: "mborish_2000" <mborish_2000@yahoo.com>
Date: 2009-08-05

That solved it. Thank you so much Klosmon. Unsuprisingly, I discovered another problem after the first one. My Effects section is always engaged and is producing some strange ring modulation type sounds depending on the value of the speed/intensity knob. Is this related to the first problem?

-Mike

--- In PolySix@yahoogroups.com, klosmon <klosmon@...> wrote:
>
> One frequent problem with the CPU board can cause unwanted modulation of
> the VCO, which can sound like what you're describing.
> To see if this is the case, get a soldering iron & lift one end of R9,
> which is a 10K resistor located between IC8 and CN05.
> This will disconnect all modulation to the VCO; if it eliminates the
> problem, let me know, and I'll describe where to go f rom there.
>
> ~GMM
>
> mborish_2000 wrote:
> >
> >
> > I've got a few problems that I can't figure out. Unfortunately, my LFO
> > is bleeding into the VCA? and I can't figure out a way to stop it.
> > It's not a violent bleed but it's enought to make the Polysix
> > unusable. If I turn all of the controls down, it is still there. All
> > of the controls are functional. All of the potentiometers test out OK.
> > I tested all cables for continuity. I cleaned the LFO modulation
> > select switch and replaced the 4051 on KLM 369 without any luck. I
> > read somewhere that somebody suggested cutting a trace, but they
> > couldn't remember enough details about what they did. I didn't see any
> > calibration proceedure related to the LFO modulation either.
> > Everything else works fine.
> >
> > Does anybody have any suggestions? Logic and microprocessing are
> > really beyond my knowledge.
> >
> > -Mike
> >
>
>
> >
>
>
>
> [Non-text portions of this message have been removed]
>