I don't have a listing of a 5F alarm either. If you look in your electrical cabinet the Z axis amp should be displaying an alarm code as well. What is the drive saying? What model is the drive?
PS- A 700/70 Series Handbook says that a S03 005F alarm is the external contactor points are welded together. This could be an external or could be the internal contactor. Also I have seen the scr bad and the red DC Buss indicator lite on the base of the drive is not on. Or it could be on as soon as power is applied to the machine but the servo ready signal is not enabled yet. Something to that effect. Check out the power circuit on the Z axis drive to be sure nothing is amuck.