Nextwave HD510

I feel like you're missing some of the obvious info here, because you keep posting in different places with the same questions. Don't mean any disrespect to you at all, I think you might be over-thinking things or may not realize the answers have already been provided here in each place you've posted. I agree with your frustrations about next wave and lack of third party options.

I have done the exact thing you are asking about myself with 2 nextwave CNCs; YES it is possible to do BUT you will NOT find a way to plug your old serial cables from the stepper motors into a new Blackbox controller and run it.

***Before you jump off the deep end you should realize that there are some great things about the Nextwave controller and software that you will lose (free virtual zero software being one of them that allows you to very easily set unlimited parameters of contour and zero position or z-height of the work-piece itself at the start of your project- imagine perfectly machining on a crooked piece of wood) - this is a VERY useful thing if you get into more advanced use of the machine and I have not found a comparable offering from any other third party out there- just FYI. Another thing you'll lose is the Pendant which comes built in with a TON of valuable and useful software features built into it (I spent a year using one without even realizing the other features tucked back into sub menus and accessed by non-standard key configurations). Next Wave has only recently really made an effort to even explain the basics of what is under the hood to their customers, but the control boards they use stock on the shark actually offer a higher resolution and accuracy than you will achieve with the Blackbox. It may not be noticeable though - I love the Black Box and my openbuilds machine- so don't think I've trying to downplay them.

At a technical level their controller runs the steppers at a different pulse rate and in layman's terms the communication pattern is different (not a better or worse scenario- just different)- that's why you'd need to have a separate controller with its own power supply configured to switch.

** One of the plus items that OpenBuilds has and the Blackbox specifically tackle that Next Wave doesn't is the way that failures or errors in steps or individual axis controllers are handled. The Blackbox will stop in scenarios of failure (which is actually exactly what you'd want in order to save your work piece and have a chance to restart) whereas the Nextwave controller can lose an individual axis control card and not have any red flags or stoppage, will just keep right on plowing through and running with your bit in the wrong position and destroying the workpiece and expensive material in some cases. Imagine this happening on one of your last toolpaths of a project!

One option to consider, it really was something I came up with while doing the 2nd Next Wave conversion after realizing I might still want access to the features described above, is to wire a handful of new male-female harnesses in-line of your stepper motors, kind of like a quick disconnect- and you could actually then keep all your Next Wave components, but also use Open Builds products. You'd just switch the connections at the quick disconnect location. Its kind of redundant, but it would open up the option of third party software too.

You will have to do some work yourself, but if you have experience or skill with simple electrical work or any sort of wiring in the past, then this will not be a challenging thing to do, but you will need to either cut the current serial cable connectors off and use the Open Builds cable connector harnesses or similar with the quick disconnect option.