Core one failing Y calibration
Just assembled core one for son, was working great, transported very carefully in car on padding, set up in his apt, and keeps failing Y axis calibration. Found a tie on left side that was obstructing, fixed that but still fails. Gantry is straight, belts tuned, checked y motor set screw on flat and tight. Noticed when perform y axis cal, the y position does not always change, yet set screws are tight and on flat, took right side off to ensure wasn’t filament cable and not impeding. Some time it fails at back, and sometimes fails in front before reaching y home. What else can I check?
RE:
With the printer turned off, if you move the printhead by hand along the Y-axis do you feel anything binding or getting caught? If so, it's usually the filament sensor cable it's getting caught on. If not, then most likely the gantry is not square. This can happen if the belts are tuned (screws turned) asymmetrically. I would start by retensioning the belts following the "Quick gantry alignment" section on this page: https://help.prusa3d.com/article/adjusting-belt-tension-core-one-l-core-one_845048
Be very careful tightening the belts. Both screws have to be turned by the same amount and in the same direction. A very common problem is using belt tension to square the gantry which is wrong. It's has to be bent by hand with the belts completely loose.
With all new builds and new ready-built machines the best place for help is Prusa Support via chat - you will need the serial number of your machine.
Cheerio,
RE: Core one failing Y calibration
took right side off to ensure wasn’t filament cable and not impeding.
Now that you have re-installed the right side panel, please double-check the routing of the filament sensor cable. (It is visible and accessible from the inside of the enclosure, although just barely.) When you took the side panel off you will have pulled the cable out a bit, so it might still have gotten caught in one of its cable ties and bulged inward when you reinstalled the panel.