I took apart the diode block, with the SCR, main rec and stuff, cleaned it all up checked all the wiring, did what tests I could, and reassembled it all. Everything back correct, and now the machine won't even move ! You can hear the motors trying, both contactors closing up in both directions. One contactor is new. It just has no **** , a few hours ago it was running around the shop full speed. w.t.f. !!!!