Y axis moves backwards during print


Strange problem while printing.
Y axis moves with each move more backwards

motor works fine

I ve tested and seems with each movement of the y axis it sets the new position as home for y.

The print bed nor anything else hits the endstop wile moving.

does anyone has an idea what could cause this ?


Your description of the problem is a little hard to understand.
Just a guess did you check the screw that hold the pulley on the motor to make sure it’s tight?
Also check all of the reference voltages.
Set them to 0.55


voltage already set to 5.5
bed moves fine when moved manual
set home position then works fine but after a few moves in y direction loses coordinates and seems last position becomes y home
screw on fully motor looks fine but i will check one more time

but everytime y moves back it seems to lose it coordinates a the y home becomes the last position.

i would guess problem with the y switch ?

or replace the y motor ?

When the K8200 first came out the firmware monitored the end stops.
Normally this is not a problem.
However on mine the wires for the Y end stop were rubbing on the back of the frame.
One of the solder connection became weak when the cable for the end stop went over one of the cable ties I would get an end stop hit (you could see it in the log area) I fixed the solder joint and cable tied the wires so they did not stick out anymore.
Velleman came out with a firmware upgrade that does not monitor the end stops after the print starts.

Short of the long check the solder joints for the Y end stop and fix them if needed and consider upgrading the firmware if the above fits the failure.