CR10 v2 Y Axis Layer Shift
I got a new CR10 v2 (Nov 2020), stock firmware (no real mods). I've successfully printed a few things and today I went for a big item, mandalorian helmet (in 2 pieces). It prints fine till around 110mm (99 on one and 111 on the other) the layers start to shift. The pattern isnt exactly the same so I know its not a slicer issue (cura). Not to mention i've printed this same helmet on my Ender 3 (just 20% smaller) successfully. Seems like this issue arises on a bigger print (print time). Height has nothing to do with it, i've successfully printed tall be small prints. Seems like after 8-10 hours its happening. I hear an auditable THUD from somewhere. This is obviously when the shift is happening. Prior to the shift the print is great.
If I pause the print (moving the nozzle back to ZERO) i can hear the THUD again when everything goes back to zero (obviously realigning the shift). When I resume, it seems realigned, but I have to stand there on 48 hour prints to keep pausing the print every time i hear a THUD!.....Putting a desk fan blowing in to the control box seems to help, but it still does it randomly.
I have checked the machine once or twice over of all the common solutions for layer shift and everything seems as it should be
Belts are tight but not too tight
Grub screws on the stepper motors are tight
Wheels under bed/nozzle/Z are snug (but not overly tight)
Nothings in the track or preventing movement
I'm stumped on this one, especially cuz i dont see any shift till im almost a half day or so in and it prints smaller items, even right after this fail with no issue. Is this a flawed mainboard?