9 point check
After I have loaded a design into printer. It goes to the left front and will start to check the 9 points. It will do the front 3 points with no problem. When going to point 4, it stalls and makes a noise like it is hitting the back. It will than do point 4, 5 and 6, but again, going to point 7, it stalls again and makes even a larger noise like it is hitting the back of the sheet. I have to stop the print because it is only 1/2 way on the sheet. I have done a calibration and than a self check. And everything is ok, but again, when I load the print, I have the same problem doing the 9 point check. Any ideas what I am doing wrong or what I need to do to fix this. Thank you.
RE: 9 point check
Is the filament spool free to move? A check would be to start a print with just a stick of filament cut from the spool and look for the same behavior.
The other likely problem is dry sticky Y axis bearings that weren't lubricated when installed. This is often made worse when the U-bolts are over-tightened and they compress the Y bearings. These U-bolts should be snug enough the bearings don't wiggle, but not tight.
Also, the cables must be self supporting and not dragging on things where they will snag.
ps: the self test and cals can pass because movements are pretty slow - the printer moves faster once you start a print.