Geeetech

Hi, my printer, an i3 pro b, was printing fine yesterday, but today it always prints the second layer exactly 20mm closer to y0. It does this in all software. I've tried reloading the firmware and that makes no difference, anybody got any ideas?

It could be a motor controller going bad. You can try changing it with the one from the x axis and see if the problem follows the controller chip.

Maybe your feed rates in the printer settings of Repetier Host are setted too high.Try to set a lower value and check whether the problem are still there.

solved, grub screw on the y pulley had worked itself loose, used some thread lock this time so hopefully wont happen again

Congratulations on finding a solution to your problem