Problems after change stepper drivers

ttdriver87

Hello, I have changed the stepper drivers to LV8725. I also have changed the part cooling fan and all igus. 
After i have changed this the prints are terrible. I have no idea what is the problem. The Extruder is calibrated. I hope somebody can help me. The picture with the ready printed part was printed before I have changed the stepper drivers and the part cooling fan.

ttdriver87

I think I have found it.
i am an idiot!
the Stepps are wrong.
now the Stepps in marlin are 640/640/3200/790
i think the z Stepps are wrong.
it might be 
640/640/6400/790

Laser8302

So LV8729? Did you set your jumpers for 1/128 steps? And then original steps per mm are 80 with microsteps set at 1/16. So yes you are correct, 640 for X and Y. 6400 for Z is also correct, unless you changed out you lead screws.

ttdriver87

A nother problem now. The z axis move slowly and with breaks. I have changed the Vref from 0.75v to 0.9v but nothing changes.
Can somebody help?

Samuel Pinches

Typically this behaviour is seen if

• There is not enough power going to the motors --> increase the stepper driver current
• The stepper drivers are overheating --> decrease the stepper driver current, or add cooling for the stepper drivers