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
>
>
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