I am not sure how your X3 was wired but I wired mine per instructions found on the SyilAmerica website. An inline fuse holder was used in my machine and it is wired to a bus bar accessable from the top rear cover of the X3 control box. I wired mine with the inline fuse holder at the the bus bar end towards the top, but it could be postioned towards the bottom end. You should be able to trace the wire by removing both covers from the back, be sure to disconnect the power line first. It may have been done differently on your machine, but you should be able to trace the wires to the receptical and find an inline fuse if there is one. There are 2 other fuses that I am aware of( one on the spindle board[big PCB] and another on the BreakOutBoard, but I doubt they would have burned out from plugging the vacuum in. Hope this helps you out in some way.