Partially Solved Stepper Motor Stopped Turning

Which motor (which axis) exactly is the

Sort of depends on which way you look and turn your head

X? Y? One of the Z?

Not that it matters much any NEMA-17 stepper the same size and step angle will drop right in (1.8deg step angle) Not sure how much torque is on the stock ones, but 35 nm-inch or more should be fine. I used these: https://smile.amazon.com/gp/product/B00QEXSCE8

 

They are a drop-in in terms of step angle (so Z steps/mm should be the same). Like I said I can't speak for the torque numbers because I don't have them for Robo motors. These work though...

If you want to replace them both it is not a bad idea. I would suggest swapping the stepper driver for the Z first to make sure that the motor does not work on another axis -- no sense replacing a good motor if you have a bad driver

 

Just swap the Z motor connectors on the RAMPS and if the "left" one stop working then it is the driver, not the motor.

 

The R1+ uses integrated leadscrews. It is possible to dismantle them from the stepper but not easy or simple. You need a new stepper with a leadscrew. Getting the exact one from Robo is ideal, but I know not if they have any in stock. The alternative is to replace both z steppers with new ones (different sized leadscrews) there is at least one thread on this. I can find it tomorrow. @WheresWaldo created that thread if memory serves.

 

@CCJ that is an issue with Robo using what appears to be a stepper with very limited availability I am pretty sure the thread is a TR8*4. When I did my upgrade from readily available parts I could hardly find any that size, there were a lot of TR8*8 and some TR8*2 so I originally started with the former then upgraded again to the latter.

Not even http://www.omc-stepperonline.com has any with that threading that is long enough for the R1 (300 mm).

You could always just use a coupler on one side and use a standard stepper and a lead screw that matches Robo's specs.