Belt test fails on X Axis length 50% of tests (alternating tests) - Layer shifting.

[Solved] Belt test fails on X Axis length 50% of tests (alternating tests) - Layer shifting.  

New Member

My Prusa i3 mk3s has been running for a couple of weeks with good results.

I switched to using PC blend and so upgraded my firmware to prusa3d_fw_MK3S_3_9_1-RC1_3512.hex for PC blend support.

I then noticed some intermittent X axis layer shifting.

I switched back to PLA in case this was a PC blend issue, but still saw X Axis layer shifting.

I downgraded the f/w to 3.9.0 but again still have the issue.

I have checked everything I have found on line and every things seems to move freely and withing obstruction.

Interesting, when running the Belt test, it fails with "Selftest error! Please  check : Axis length Axis X" exactly 50% of the time.

Eg it passes, then fails, then passes, the fails ... (you get the picture).


What am I missing? All was going so well for the first week or so.



Posted : 14/09/2020 3:39 pm
New Member

I was completely thrown by the alternating reports of pass and fail on the belt test. It turns out that the troubleshooting advice general given was spot on.

The X-axis pulley orientation was incorrect every other test.

I had [failed to] tighten the two grub screws in such away that it ended in the correct position after every other stop (which was when I looked at the position) and then twisted a degree the alternate time.

Correctly tightening the two grub screws resolved the problem.

Posted : 15/09/2020 9:03 am
Jerry liked

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