Hi, I've just converted my AR4 to. a MK2, I had a 24VDC/7.5A power supply on hand so I decided to give it a try. It's worked well so far. I have also piggy backed the Pneumatic valve from the same supply, just installed some protection across the coil to suppress the back EMF.  I checked the current draw while doing a Homing Cycle with the Pneumatic gripped energised and it was only drawing 5.3A.