I made the same big assumption! I wired the new power supplies up to the terminal strip, and the control fired right up. However, it wouldn't run properly. There are a number of wires that run between the control and the power module, and most of them do not go through the terminal strip. I spent a LOT of time finding out which wires carry voltage to/from the control. I started by tracing back circuits from the LED indicator panel. Although I managed to figure out which wires carry which voltages, I didn't bother trying to wire in any sort of jumpers. I came to the conclusion that I am putting in WAY too much effort into a control that will likely give me more problems in the future. As soon as I had good clean regulated power running the control, something else would probably take a crap.
Anyway, I am pretty much set on the idea of a retrofit. I now have to learn everything about them and figure out what all I will need. I'm sure it won't be easy, but I should end up with a machine that is far more reliable and serviceable. It should be relatively affordable, too. Parts & Smarts wants something like $850 for HALF of the original power supply (which is a POS to begin with). If I can retain the servo motors and spindle drive on my machine, it shouldn't cost much to retrofit to Mach3 (just a lot of time and frustration.)
So, what's the scoop on your Tree? Have you been able to make any progress with it?