A device and associated method for adjusting the opening pressure of an implantable valve. The valve has a rotor of rotation axis, whose angular position determines the opening pressure. The rotor has a rotor micro-magnet movable between positions of locking and unlocking, in which positions the micro-magnet respectively prohibits and permits the rotation of the rotor. The method includes: arranging a locator to align an axis of a locator receptacle with the rotation axis and to orient the locator in an angular position； determining the angular position of the rotor about its rotation axis with respect to the locator； inserting an actuator into the locator receptacle as far as a first insertion depth； partially withdrawing the actuator from the locator receptacle as far as a second insertion depth less than the first insertion depth； rotating the actuator starting from the second insertion depth； separating the actuator from the valve.
