It has been a long time since I had to do this but I remember that you could generate a fixed range marker by winding on a calculated distance in yards (N/S and E/W) onto the internal offset potentiometers of the CU 585. I think you could do the same with the external offsets also. You had to have the Shift selected off as you could not drive the usual markers out ahead of the aircraft (as they had failed). Photo of CU 585 attached.
