I have a 2005(ish) Sharp SV2412 that has been sitting idle for 2-3 years (I'm new at this company). I'm trying to get the machine back up to a point where it's useable. I've already done all the obvious stuff (oil/coolant flush). I'm at the point where I'm trying to figure out how to home the machine.

When I start the machine up, and switch to zero return mode, I get an "overtravel Z" error and the Z axis position from the machine position menu is +1.9812. I can see that it hasnt tripped the limit switch for home yet - so how do I get it to travel back to the home position? Is there a battery I need to replace for the encoders since the machine has been idle for a number of years?