Bed Level off after hearing a bang

[apostoly]

I calibrated my bed last weekend after taking the hot end off and mucking around with the printer. Now today (after printing successfully just last night) i am getting horrible prints, so i decided the check the level of all the towers and it seems like each are off with only one where its supposed to be (Y tower)

I then remembered the issue with stiff U Joints which im going to take off, sand and re lube. This could very well be my issue. I'm just thinking what else could cause this? Belt tension? Cheap skates not tight enough? (belts might need some tightening but very minor and skates are fine as i tightened them not too long ago)

Another thing that was really strange that actually happened this morning and is the time i noticed everything started going wrong. I was printing away and all of a sudden i heard a loud thump and the print head was about an inch above where it was supposed to be printing and extruding into the air. Now i have no idea what that was and what that could have been and am assuming its what caused the issue?

Paul

[Polygonhell]

I would check your belts, if the pulley slips on them it eats the teeth on the belt.
I would also check all the pulleys are tight on the stepper shaft.
Could be a frozen UJoint I guess.