Next step is to begin eliminating possible causes. Lift the end of R11
to see if the effect goes away. Then lift R9. R11 carries the internal
mod signal; R9 carries the signal from the mod wheel. If the effect
continues with both of these disconnected, it's coming from somewhere else.
You then have to backtrack through the opamp buffers & demultiplexers
for the VCO control voltage.
It is sometimes possible on battery-damaged boards for a signal to bleed
through to other traces.
~G
On 8/10/2015 1:33 PM, moogchild synthdrome
moogchild@yahoo.es [PolySix]
wrote:
>
> Definetely not, I've double checked it. Effects off, sawtooth wave.
> Same slow VCOs modulation (about 5 secs per cycle) independently of
> the speed of the three LFOs in the Polysix. If I replace the KLM-367A
> the modulation disappears.
>
> --------------------------------------------
> El lun, 10/8/15, backshall1@bellsouth.net [PolySix]
> <PolySix@yahoogroups.com> escribió:
>
> Asunto: Re: [PolySix] VCOs slightly modulated due to battery board
> malfunction
> Para: PolySix@yahoogroups.com
> Fecha: lunes, 10 de agosto, 2015 20:57
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> How about PWM Speed or Effects Speed? They also have
> their own LFO signal
> that could be bleeding in somewhere.
> Don B.
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