pretty sure if you get a usb floppy emulator $30 and plug it into the floppy cable it will fix it or just get a used working floppy drive. then you can just copy your nc programs onto the usb stick and plug it in the front of the machine. only catch is that you have to format the usb sticks a bit weird so you have multiple 1.44mb drives so the control can see them. also gets fun splitting up larger programs into 1mb files if its a really large program.
i would guess there are still some programs stored in the control so load them and see if they run just set your g54 z on part setup a long way from the spindle and dont put a tool in to avoid a crash. if your outside the machine limits centroid is pretty good at telling you when you push start to avoid a bump. if you can get it to do that and verify all the axis move as expected you could just use it once the floppy is fixed.
yeah its old but what you planning to make on it? i have an acorn and an oak on my machines. one good thing about centroid is if you can work one of their controls (even an older one) you can pretty much work them all, the basic interface between them is fairly similar. The thing that gets better with the newer controls is usability, processing power for more complex code and features like touch screen, configuration wizards etc better code look ahead! BUT the basic underpinnings of the system are on similar building blocks.