Qidi confirmed that it was the stepper motor cable and sent me a link to purchase. But I just got the repraps from Amazon and spliced on the Qidi motherboard end connector from the old bad cable and my X One is back in business. The reprap cable motor end was the same as Qidi cable so that made it a little easier. But what a PITA. 2 intermittent cable failures (other one was a limit cable) in maybe 3 months of use. I am getting where I can't recommend Qidi printers anymore unless/until they figure out a way to make their cables hold up better. As it is this thing needs way too much maintenance.