Odd stepper issue on Y axis

For a while now my TAZ5 would make a loud ‘click’ as the Y axis moved forward and back. It was intermittent… middle of a print, it would start, then stop a few minutes later. Sometimes before I had time to go check it.

The times it was clicking, I checked everything I could see. The click sounded like the bed was hitting something, like it was banging into something as it slid forward and back. But there was nothing in the way. The bed moved freely. Maybe it was coming from the stepper? I don’t know. My prints were fine, so, I didn’t worry.

Just now it was clicking and I went to check it. This time the print wasn’t fine - my Y axis slipped and everything was shifted off a few MM towards the front of the bed. Dammit. Ok, lets investigate. Cancel print. Turn motors off. Move the bed and… the bed won’t move. Turn stepper off. Again, again. Steppers won’t turn off. Check X axis… that moves. Manually turn extruder gear - it turns. Move Y axis - nope, it’s locked.

Ok, weird, lets totally power it off. The Y STILL won’t move.

Turn it back on, connect, jog the Y axis through the interface. It moves. Power it off - won’t move.

Whats going on with my motor?

As a possibly related side note - the shaft on my X axis actually snapped in half inside the motor body 2 weeks ago. Wasn’t even stressing the printer, just doing normal prints at about 60 mm/sec. Only bought the printer 2-3 months ago - was there possibly a batch with bad motors?

Going to call support tomorrow and see what I can do about it, but in the mean time - why would my Y axis motor bind up, even with the power off, but still move when printing? And of course, there’s the clicking, and now the misprint…

There was a batch of bad motors with shafts that weren’t properly hardened. Most of them were in the mini line.

Check the y motor pulley, if the setscrews are loose it could be moving on the shaft.