Solved Z-axis motor grinding

Hello all, I have a Robo 3D R1 Plus that was purchased back in May. The issue I'm having is the left Z-axis motor is making a grinding sound and moves slower than the right motor/rod. I had this issue in the past as well, but seemed to "fix it" by simply unplugging the motors under the printer. I have tried that this time to no avail.

Any help is much appreciated!

 

Okay, fairly certain it's a bad stepper motor and intermittently has problems.

The first time I swapped the cables, it seemed to be working perfect. Both motors were moving as expected, I didn't hear any sounds.
The second time (so this is swapping them back to their original positions), it seemed to be working perfect, but I noticed a feint sound coming from the left motor that I didn't hear from the right, not nearly as loud as before.
The third time, the loud grinding noise was back and the stepper motor was moving slower or not at all.
Swapping them a fourth time, same results as the third.

In order to swap the cables I do have to flip the printer onto it's side, not sure if that could be affecting anything.

Thank you for the help!

 

Oh, perhaps I should stop doing that then

Is there an easy way to check what the stock motors were? I did some searching but couldn't find a straightforward way of figuring that out. And what would be a good replacement motor? I couldn't find any on Robo's site and not sure what torque/amps/volts to get.

Thanks again!

 

Awesome, I'll pick up two of those and just replace both. Thanks for the help!