You won't loose a ladder from dead batteries. If the pc cassette is missing as the tech said, then yes your ladder is gone forever. You would need to find someone that could re write the ladder and burn it to the EPROMs on the cassette. Truthfully, if you want to save the iron, a retrofit might be in order. Possibly save the fanuc motors and drives and use something like mach3 or a newer fanuc. Either way some engineering would be required. I've seen some retrofitted machines like that with no documentation, it sucks for sure.