If you are feeding the monitor an SDI signal this is normal as there is technically no phase to adjust in SDI as the signal is a always a digital component format (YCbCr or RGB). If you feed the monitor an analog composite video signal the phase knob will then automatically become active. Though we strongly advise against it there is an option to unlock the phase knob for SDI signals from the System Menu. If you would like unlock the phase knob simply go to the System Menu, select SDI HUE Adjustment, and change this to ON from the default OFF position.