Hi Hugo,it’s my believe that we may have similar problems.My bias adjustment cuts in/out when any kind of pressure is applied to the top of the knob.It does this in both pre/post switch settings for fuzz selection.Faulty knob perhaps?. Same problem with the tone knob, cuts in/out when slight pressure is applied side to side and on top. These all happened at the same time with no expression output.It’s a mystery to me.I would guess it feels like a poor connection.The bias adjustment when it did work properly was kinda useless for me,I left it full clockwise position.