TAZ 5 x-axis stops moving but motor is still running, how to fix?

I’ve had my TAZ 5 for about half a year now, and every once in a while my x-axis stepper motor won’t drive the belt. I can hear the motor turning, but the axle itself doesn’t move. This results in the print job suddenly becoming 2D, ruining the print. The motor makes a much louder whine as it fails to turn the axle.

My quick fix for now is to loosen the belt and move the carriage left and right, then re-tighten the belt and verifying it works. It’ll work for another few prints (~5ish), then the problem will resurface. My guess is that I’m overloading the motor somehow, but not sure if that’s really what’s going on. I haven’t done any disassembly other than that, but wondering if other people have experienced this before.

I do notice that my z-axis is slightly out of alignment, ~0.5mm, though I highly doubt from reading other threads that this little misalignment is causing the issue. The motor isn’t hotter than the other motors (sensing by touch), and the axle on the stepper motor appears to be straight enough.

Has anyone else seen this, and if so what was the best fix?

If the motor is turning but nothing is happening, that usually indicates that the motor pulley setscrew is loose. If tightening that or replacing the pulley doesn’t do the trick, you may be ending up with a wire short. A stepper motor basically has 2 sets of wires that drive two coils. If one of those coils has a short, or even worse, is reversed, the motor will not turn. Think of it like two people trying to push a car down a road, if they both push the same direction, the car moves. if one pushes the opposite direction, or if one gets tired and stops pushing, the car doesn’t move, or only moves a little. Check all the cable fittings from the motor to the board, and if you don’t find anything, consider replacing the wire run entirely for that axis.

It is theoretically possible to break a motor shaft, but if that was broken, it wouldn’t be working at all anymore.

Overheating on the rambo board can also cause something similar, but usually it will be all axes, not just X. Check that your electronics case fan is running while the printer is printing. On some firmware versions, it slows down when the printer is idle.

I had tried plugging in the x-axis cords into the y-axis and it moved no issue, so I don’t believe it’s a short, or it’s solely on the motor side of the wiring (didn’t try using the y/z controls on the x-axis). Set screws are as tight as can be, and the rambo board is blowing.

The part that confuses me is that as soon as I remove the belt, the motor works just fine, which leads me to believe that I’m simply over-tightening the belt, and that extra linear load on the pulley, which in turn is preventing the motor from producing enough torque to turn when a small extra resistance is added. The bearing on the other side spins freely. Is there an actual recommended amount of tension required? Everything I’ve read simply states to not overdo it.

Another thing that could be important is that when it’s jammed, I can’t move it when it’s off, but I can once I clear it, next time it jams I’ll check to see where the belt ends up, as I’m writing this, I’m thinking maybe the bearing on the right side has a little too much play and the belt jams there.

Thanks for the assistance, piercet! I do like your other post about the openrail x-axis, looks like a daunting design!

Hi 3nixPrint,

were you successful in resolving the issue with the X-Axis motor in your TAZ? I’m having a similar problem with my Mini. I started a ~11 hour job last night and when I checked on it this morning, it had gotten about 80% through the print, then the X-Axis stopped towards the left side of the axis and dumped filament for the rest of the print. It appears the Y axis was functioning; the build platform shoved the filament hairball all over the workbench in the +/- Y direction.

Any feedback would be awesome!



So far my only fix is to remove the belt, move the carriage back and forth, then reattach the belt keeping it centered on the bearing opposite the stepper motor. I’ve been keeping an eye on that bearing since I last did this and the belt seems to stay centered. Until it happens again, I can’t say for sure if that’s the cause or not. I also verified the stepper motor would turn before reattaching the belt.

Hopefully that helps, it’s quite demoralizing when you lose an entire day’s worth of printing.


You might want to check your X axis bearings for foreign matter. Last week I had my Y axis jam because I let some stray NinjaFlex extruded thread get on one of the Y axis rods. When that stuff got into the bearings things came to an abrupt stop.

Just happened again. This time, I can definitively say it’s the motor. When I removed the belt, the motor still didn’t move freely, however a small nudge to the main shaft started the motor turning again. Both the set screws are as tight as possible on the shaft, so there could be some internal problem in the motor. I did try manually turning it when it was in the stuck position, no avail. Once it was turning freely, I could easily turn it by hand.

Do you think the motor would just need replacing or simply some cleaning? The only thing I can think of is that the motor is getting stuck on the electromagnets somehow (similar to how an old reciprocating engine could need a smack to move the piston ever so slightly to get it out of a stuck position). I honestly don’t believe that’s the case, but can’t really figure another reason it would stop turning.

There is nothing to clean on the motor. Binding against the magnets would be a internal bearing failure then to allow that to happen.

yeah, if the motor itself is frozen, it’s either bearing or shaft damage.

Guessing from piercet’s response on this forum about the Lulzbot Mini, it could be something to do with the bearing. This just happened consistently for a few prints, and when I removed the motor and turned it by hand, there were moments where the resistance increased for no discernible reason.

One thing I did note: I started printing with a bigger layer height (translating to faster print speed) and it seems to work. When I was printing 0.1mm, I turned the print speed down to 15mm/s for the outer shell, and it happened more regularly. At 25mm/s with 0.14mm height, it seems to have less of an issue. This tells me it could either be something with the bearing or perhaps this particular motor doesn’t like to step slowly anymore. Will likely (eventually) just replace the motor and see if that clears up the issue.

Just thought I’d post more notes. Thanks for all the help everyone!


My x-axis had trouble moving and after inspecting everything we decided to unmount and check the motor itself. We discovered that the shaft was broken and after opening it fully we discovered that some parts (the black plastic ring in the middle) looked burned.

We’ll be ordering an new motor, any advice for future use? Is this something that happens often?

I have picture is anyone would like to take a look.

Cheers! Hope this helps!

There was a bad batch of motors that went out with mostly Mini printers, but a few of the Taz’s got them as well. I would consider calling support about that one even if your printer is out of warranty. It shouldn’t happen ever really, but I suspect that the shafts either got untampered from machining, or were never hardened by the motor manufacturer to begin with. it only seems to affect a few motors though, I know of a total of 30 at this point, almost all Mini motors.