I had this happen to me on my X driver, caught it in time and it didnt destroy the mosfet?? I had a thread on it a few months back, I had the same connector burning problem. I cut the connector in two and replaced the bad half of it with some push on connectors, no problem since.
The X and Y driver connectors were both discolored, the Z driver was OK.
edit: this is the thread, post #7 has pics
Stepper driver connector
My X axis became erratic today, upon checking the 5 pin connector on the driver, it is toast!
I thought I saw a post on this in the past but I cant find it now, I would think Mouser or digikey would have one if I knew the ID number of the connectors involved. Anyone have any information on these?
The connectors on both X and Y drivers are discolored, the two lower pins are the worst, they appear to be a bit small to carry the current required?
Any insight on this would be much appreciated..........