Z-axis driver weird movement UM2

[davidvoboril 0]

Hi guys, had someone of you some issue with Z-axis movement on UM2? My one doesnt move in normal way, its just randomly moving and just in down direction. When I try to move screw manually it goes pretty easy so it seems to be an electrical issue. I ve measured stepper resistance and both coils have the same resistance. When I try to swap stepper from Y-axis to the Z-axis driver it does the same weird movement. The pcb around all drivers has an yellow shade, probably caused by high temperatures. Does it mean I have broken complete board?? 😕Thank you very much for any advice. Happy printing 😉 And I forget to say I got the ER06 error but the limit switch is well connected and also function is ok.

Edited February 13, 2019 by davidvoboril