Print quality struggle

Hello everyone.
I am experiencing a loss in a print surface quality.
Those problems are mostly visible for round objects like on the photos. The surface is most uneven just behind the seam but on the rest of the surface it has better and worse spots.
To solve this problem I have aleready replaced nozzle, hotend, heater+termocoupler, PCB, and main cable. Nothing helped and problem is still there. I have no other ideas so maybe someone have had a simmilar problem and can help me?
I am thinking main board or something with the whole printing head drive. I have checked for woblyness and sotted nothing.

Settings:

Z-ULTRAT
0,14mm layer thickness
high quality,
30% infill (but that doesnt matter in case of this project as it is hollow)

Check your timing belts & pullies. I your timing belt pully setscrew comes loose, your machine is no longer funtioning with an accurate X-Y coordinate system. My machine is lightly used and I keep finding loose setscrews. Iā€™m pulling them out, cleaning the OIL off them and then resetting with a light touch of blue loctite.

1 Like

I will check that. Thank you!

Rrroadster, another top idea. Thanks!