Y axis not going all the way back
I just finished assembling my Core One+ and when I moved the extruder in all directions, everything moved smoothly. I turned it on and they X and Y tests passed, but the homing test failed. As I was adjusting the belt tension and calibrating I noticed the belt came out of the holder behind the extruder! I had to unassemble the extruder to put the top belt back on the holder. I got everything back together, but now when I move the XY assembly back to the rear of the printer (Y direction) it gets stuck about 3/4 of the way back! I have to really push it to make it move back more. The belts and pulleys all look okay, I've lubricated the Y rods. It's only getting stuck at this one location (right around where the filament input sensor is). The cable is not causing resistance and I don't see any other obstructions. Any ideas on what I can do to fix this please? Thank you!
RE: Y axis not going all the way back
When you say "the cable is not causing resistance", are you referring to the cable to the filament sensor (on the right side panel)? Please double-check, since it is such a likely culprit. Make sure it is routed straight back and does not bulge inwards, where it can interfere with the Y bearing.
RE: Y axis not going all the way back
By cable I was referring tot he main cable from the swing arm going to the extruder. I didn't see that it was causing the binding of the Y axis at the position it was occurring. I removed the right side panel and sure enough it was the filament sensor causing the issue! I'm going to re-route it better and make sure that it doesn't interfere again. At this time all calibrations passed. With that said, is any further belt tensioning required? Thank you very much for your assistance.
RE:
Welcome to the "filament sensor cable gets in the way" club! I am one of the founding members... 😉
At least it's easy to fix. The only thing one needs to pay attention to is that the cable slips backwards in the cable tie loops which hold it to the XY frame. You can also straighten it (push or pull it back) after you have re-attached the side panel. The cable is accessible from the inside of the enclosure, although a bit inconveniently.
If the homing (where the print head bumps into the front and right end stops a couple of times) finishes quickly and without excessive "head-banging", your X gantry is straight -- that's great. If you achieved this while tensioning the belts symmetrically -- perfect! I would still go to Settings > Manual Belt Tuning and run the stroboscope-based tuning wizard.
Not sure whether Prusa has incorporated the instructions into the build guide in the meantime? There is a dedicated page on belt tensioning here: https://help.prusa3d.com/article/adjusting-belt-tension-core-one-l-core-one_845048