I've been collecting any and all documentation pertaining to this machine and in many cases the guys I've ended up talking to are the only ones who haven't retired. Fortunately everyone so far has been happy to give me a huge data dump of everything on their drives, knowing that nobody on their end will be available to support it in a few years.

What really scares me is not the software but the aging protocols that talk to obsolete hardware. Lose one of the old AC servomotor drives and good luck finding a way to integrate a modern unit. Easy enough to mate something up to the motor and feedback, not so easy to get it to speak whatever specific flavour of SERCOS was used on the machine. At least it isn't a proprietary protocol... I'm still hoping I never have to do it.