Sujet : MF-104M issue on Mix control


I have a Moogerfooger MF-104M bought new back in 2012.I use it in the effects loop of my guitar amps and everything always worked fine, apart from the Mix control The problem is I never can pass 9 o'clock with it, otherwise the signal gets overwhelmingly wet.At first I thought this would be how the thing is, but looking at demonstration videos, I noticed that people go way over this point although still keeping a good wet/dry balance.
Does anyone have experienced this issue? Any simple fix?

please help

I did not find the right solution from the internet.

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