[sdiy] Prophet 5 P-Mod Filter Envelope turning problem

[klosmon]

Hola Gil --
If we're talking about a rev3, check the voltages at the input & output 
of the polymod buffer IC (U431 for voice 1), and the polymod switch IC 
(U459) -- either one could be bad.

~GMM


Gil W. wrote:
> Can anyone help with this please ?
>
> Under the Poly Mod section, if I turn the Filter Envelope knob all way down,
> and engage the Destination Freq A switch (on), start playing, the first note (osc 1) pitch is way up in relation to the note played. When the rest 4 oscillators are played, there is no different in pitch whenever the Freq A switch is engaged or not (same pitch when switch is either On or Off). Only for the first oscillator, if I switch the Freq A button On, pitch will raise...
>
> I tried to fiddle with each of the trimpots in the poly mod section but non of them controls the pitch. Also switched VCA chips in the P-Mod section between osc1 and osc4, the problem in osc1 remains and osc4 works ok with the CA chips switched...
>
> any suggestion where the problem can lay ?
>
> Thanks a lot for the help !
>
>
>       
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