thread break one needle only

[Shuffletown Embroidery]

I have just done all the lubrication timers on my 2006 XT. I replaced a few marginal thread feed rollers and pinch feed rollers. I changed out all the needles. I WD-40ed the hook. All other parts were fine. I also upgraded to AOS10.
The machine is running great with the exception of one needle that is breaking the thread. It's a fuzzy break without a slingshot. Other threads in the same sewout were problem free. I'm pretty comfortable that the problem is isolated to this one needle. I tweedled with it, adjusting the orientation, played with the presser foot height, replaced it, all without success. When I switched the same thread to a different needle for the same sewout, the problem went away.
What have I overlooked? Since the maintenance, I have sewed on every needle without problems except for this one. Any suggestions would be greatly appreciated.
Thanks in advance.

[ckramer]

Hope you get an answer on that question as I just ran into the same problem this week. Just one needle causing trouble. I checked all the things you mentioned as well. The only thing I haven't done is take it apart to see if the gear in back is okay.
So, hoping you get an answer!

[Shuffletown Embroidery]

I called Melco yesterday and Sal says that the problem has to be located starting at the tension feed down to the lowest point of the needle at bottom center. He walked me through a couple of visual checks to see it the needle looked off center in the bobbin area, or if the needle wasn't the same depth at bottom center as other good needles are. That all looked OK, but my old eyes could have been fooled.
So, I took the pinch roller off to double check on the grease. It was OK, but when I tried to put it back on it resisted, so I just put in a new one with plenty of grease. I also tweaked the needle plate since the needles weren't exactly centered.
Problem solved.
I think it was the pinch roller. I still can't see a problem with the posts and I don't see a crack, but I think one of the posts must be bent. The needle plate being slightly off center should have affected the other needles but I'm sure the adjustment can only help.
Good luck trouble-shooting yours.