hi sorry to jump in on this i have a ncb 280h welder which has served me well for the last 10 years or so , unfortuneately the printed circuit board in the wire feed unit has decided to blow out some tracks along with the top fuse on wire feed control panel (nbc wfu) ,any information on the wiring for this machine or possibly how to source /repair the pcb . many thanks seanI have just sent you the wiring diagram for this machine and some comments, then I read this post. The diagram sent also shows the 115V and 24V supplies for an external feeder, as well as the 7pin connector pin-out. You may be lucky and find that the F40 feeder you have is multi-voltage and will work from 115V. I would be careful using the 24V supply for the feeder, as on the Butters feeder, this only did light duty for the trigger relay and possibly the gas valve (can't remember exactly).