The pen had an issue with start up- mine didn't kick on until 10.5 volts with ttech cart and 11 with cheyenne carts but it turn out a lot of machines were sent out with the hawk cord/ with critical psu with kick start option on--cheyenne sent me the pen cord asap and now that shit rocks- 3.5 and it kicks on with either cart- it had me crazy nervous but now I'm cranking out bangers with mine nonstop- I was scared but now I love it- bye I also own a lton of machines (I'm a machine junkie) including a stylus but I can't put the cheyenne pen down!!�� try one if you don't like I'll buy it off you-