My original plan was to use the power supply from the Lulzbot Taz. It has a lot of hours on it, and while I'm taking things apart, why include an older element. I only assume the cause of death for the old RAMBo controller was simple age. 

New 24 volt, 500watt power supply, and a switch to turn it on and off with.

I had used this switch module before years ago, and ordering it again, nothing had changed. For one the switch is installed backwards, I needed to pop it out, and turn it around so the wires lined up nicely. The switch lights up, so the power must go in on one side and out on the other and with the original orientation the lines had to go diagonal, and I didn't like that.

The other thing I don't like about this switch is how the fuse is implemented. There is that strip across the back of line voltage, just open to the world. I plan to put this in an enclosure, but while bench testing this can be a real hazard.

I recently purchased some wire ferrules and a 4-point crimper. It makes wiring to screw terminals nice and clean, and there are no stray wires. While the ferrules are rather generic, get a good crimper. I've used ferrules where I had to crimp in several places for them to hold, and it was a pain. A good crimper makes installation super simple.

I tuned the power supply to 24 volts exactly with a Fluke 87v. I might have a voltage display in a box somewhere that I may add to the system just to have another readout.