hi.
i have an old printrbot and i have some problems with the board.
it started with the feeder motor not running, i have change motor and wires stil wont work.
and the hotend wil get hot but not cool down again.
the bord wil not connect to my pc without power from powersupply.

sorry for my bad English.

i hope you can help me.

This controller has on board stepper controllers. It is likely that this has died..

if the mosfet wont switch off it needs replaced.

regarding power, this board isnt meant to power up without external power

You need to replace the board or learn to fix electronics and replace the mosfet and the stepper driver