XL 5 head, Diagnose alignment tower
My first and second XL print went great. Then I ran into Head docking problems. As I had just set my printer up, I thought it might be my belt tension.
So I fiddled with my belt tension, but I don't understand the belt alignment check instructions.
My issue was the nextruder dock screw loosening.
But now my alignment has an issue, but I don't know where to begin fixing it, or how to complete the belt alignment check
RE: XL 5 head, Diagnose alignment tower
I'd recheck all of your docks and make sure they are tight. This is critical. Removing the metal cover on the back can make this task easier and it's only a few screws. Then re run the dock position calibration.
Probably wouldn't be a bad idea to run the nozzle calibration also, but make sure all of your nozzles are very clean. There can't be any plastic on them or buildup.
Then follow these instructions linked below. There's a how to video attached to the instructions. The belt tuner is sketchy in my opinion, it can get you close, but the readings are sometimes wildly different. I'd use it to get you in the ball park, then make sure the gantry has no gap when moved all the way forward on both sides. It should not move at all when squeezed. If it does tighten it on the side with the gap slightly until there is no gap. Then recheck the other side. Repeat until both sides are good.
After competing this you may find that the tuner app says the belts too tight, but having the gantry square is the most important part. I've had discussions with support and they actually advised me to ignore the app and go tighter to get everything square.
https://help.prusa3d.com/article/adjusting-belt-tension-xl_401793
Good luck.