Audio Centron was the Crate pro audio line. Loud technologies now owns the Crate lines. COntact Loud and ask if they have the information.
Meanwhile, the crossover is not all that complex. If you cannot eyeball the signal path, you ought to be able to trace it out and draw up a diagram. You will probably have resistors, caps, and inductors, and maybe a light bulb. Unless they are visibly melted or burnt, the inductors rarely fail, other than to break free of their solder, or maybe a wire end breaks off. Caps go open, they go short, they break free of their solder, or break a wire off. The resistors go open, then break free, break wires. And the bulbs, they burn out, the socket fails, or the wiring breaks free.
Those are all things that are fairly easy to check.