I managed to temporarily wire up the spindle over the weekend and isolation routed the above PCB, it wasn't until assembly that I realized that I had still managed to get the +5 and +12v wrong. DOH! I had a short male to female extension lead kicking about, so just flipped the red and yellow wires to test out the board. The design and manufacture were good, everything fitted nicely and the board worked as expected. I have however, since tweaked the design yet again, along with a redesign of the IO board. I now have a single 4 pin connector that will supply 5v & the Estop position to the IO board and it will also send the charge pump signal from the IO board to the power board. Hopefully I can get the 2 new PCBs routed and assembled this week and get them tested.