impulse 500 and the eq knobs dont register properly

impulse 500 and the eq knobs dont register properly, have the latest dj softeware and latest firmware and tried the controller on 2 different macbook pros running the most update ios and the latest version of virtual dj, the software is correctly reading zero when all the way anti clockwise, and 100% all the way clockwise, but only one registers knob half way correctly. manually adjusting the eqs to the middle on the software has the actual dials pointing in all different directions. does anyone know how to factory reset or recalibrate the impulse 500?