Roko These might help:https://github.com/repetier/Repetier-Firmware/wiki/Hardware-settings-and-print-quality<br/>https://www.matterhackers.com/articles/3d-printer-troubleshooting-guide<br/>https://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide<br/>https://www.matterhackers.com/articles/how-to-calibrate-your-extruder<br/><br/>There are literally hundreds of guides out there, based on the same general principles.
