James, I have this one with a built in CNC port. http://www.everlast-welders.com.au/product/PowerPlasma_50. It has a blowback start. They say the Mesa THCAD can handle HF start. I think HF start might be hard to control noise and may need an earth stake driven through the slab. I think getting up to a 24 volt vs 5 volt system will help fight noise but I have not fought that battle yet. I spent all of today rebuilding the bent circuit board and mounting it a bit differently (in a metal electronics enclosure). its so nice to have a mill when you are doing something like this Looks like its going to work out OK And all mounted up THe LED is just a warning light to say I have 24 volts up there for trouble shooting. It has told me about one problem already.. I am still not sure if this has fixed my problem as I did not have much time by the time I got this done.