Core One kit fails Y-axis self test - Assembly and first prints troubleshooting

RE: Core One kit fails Y-axis self test

Ticoune — Mon, 27 Oct 2025 01:29:26 +0000

Thank you Michael (chat support) ! You solved my problem. It was my fault in the assembly. I'm so grateful. I've wasted so much time on this issue. I should have chatted long before. Greatly appreciated your help. Thank you !!

RE: Core One kit fails Y-axis self test

Ticoune — Thu, 23 Oct 2025 01:25:58 +0000

Lucky Guy! I did the same and not working. Discouraged, Ive been trying so many times and wasted lot of timw

RE: Core One kit fails Y-axis self test

3D Medic Vince — Sun, 21 Sep 2025 03:37:25 +0000

85 was the original value. Now there's a newer value to help reduce the VFAs. The main thing is to make sure that both sides are flush against the front when you start adjusting the tension. My Core One has been printing pretty much without issue. I'm using latest firmware and Slicer.

RE: Core One kit fails Y-axis self test

happyday.mjohnson — Sat, 20 Sep 2025 22:58:39 +0000

What is it about 85 versus what is recommended? Thank you.

RE: Core One kit fails Y-axis self test

Coldbird — Sat, 23 Aug 2025 16:02:57 +0000

This helped me. I am extremly greatful for your answer!

RE: Core One kit fails Y-axis self test

3D Medic Vince — Tue, 19 Aug 2025 04:14:28 +0000

I just finished my MK4S to Core One conversion and had fail in y axis. I noticed the end of the carriage when all the way forward had a small gap on the right side and none on the left. I loosened both belt tensions and pressed the linear rail all the way forward so both sides were touching the end and tightened the belts till it held in same position then used the app to tune the belt s to 85 and the y-axis test passed.

Core One kit fails Y-axis self test

happyday.mjohnson — Mon, 18 Aug 2025 14:44:07 +0000

I put together the kit. All other self tests pass. The Y-axis self test fails.

-> During loosening of the left side belt tensioner, the bolt/nut seized. My instructions came before Prusa support added a note to add lubricant at this point. So, the left side belt tensioner broke and Prusa is sending a replacement.

Prior to this challenge, I tried to pass the Y-axis self test by making sure the cable and zip tie on the right hand side (underneath) did not impede the nextruder moving to the right rear.

During this process, I noticed there was a larger space on the right side (Y-axis) of the gantry versus the left side. It was significant. It was at this point loosening the belt met with frozen bolt/nut tensioner/broken part.

Have you run into a similar problem of a gantry that will not / is not square? If so - are there tips/tricks you can share?

If you have had issues passing Y-axis self test, do you additional steps/advice I should take?

Thank you.