Discussion about the Korg PolySix synthesizer

Hello all,

I've had a P6 for a year and I there is an issue about the modwheel.
What it does is:
_when Mod switch is set at VCO, then modwheel affects VCO pitch. It's OK.
_when Mod switch is set at VCF, modwheel modulates VCF AND VCO... KO.
_when Mod switch is set at VCA, modwhell modulates VCA AND VCO... KO.

So the two last position shows an issue. It is not supposed to modulate VCO each time.
On the other hand it works nice when using MG with pots on control panel.

Modwheel is linked to KLM369 then signal reaches KLM367.
Problem with modswitch? I wonder where i should start to find the culprit.
Does anybody know when the issue could come from?
Thanks for any kind of help.

rgds,

Ed.