hello i just bought a Black Knight project machine. it blows the i think its F2 fuse. its the middle one on the fuse card. if i unplug every connector on the power supply board except the 2 power input plugs it still blows that fuse. so i think its something in the power supply board ? is this right ? and if so what should i look at next ? its the earlier bk with the sys 6 boards not the sys 7 boards