Unresolved X-Axis losing position

So I plugged in my old Robo 3D R1+ to try to print some fixtures. It was printing fine until half of the print when the X axis lost position and continued to lose position every layer it went further. I thought it could be a software issue so I re-sliced the model (and different models too) and tried again only to see it fail now at the 2nd layer. From then on it kept failing after the 2nd layer. The first layer works great but at some point in the 2nd layer it loses position and it keeps doing that for the rest of the print.

The x-axis runs fine when I move it manually (with my hand and with the controls from the RepRap board I installed) and it's well lubricated. But I can hear a clucking sound (from the x.motor-belt-carriage) when it loses position while printing and I kinda feel some extra tension in the belt while it clucks.

I checked and swapped the connectors, cables, and drivers for the stepper motor but didn't fix the problem. The belt and gears seem fine (no missing teeth or worn out and well aligned). I checked all the limit switches and connectors too (no obstructions or looseness).

What I find strange is that it was working fine until half the print and now it can only finish the first layer before it starts losing position. Could it be something wrong with the motor itself?

I'm attaching videos of the clucking sound and the x-axis losing position. Any help is appreciated.

 

If the clicking is coming from the motor, consider to check the free movement of the axis when power is off. You could have a failing stepper motor driver and may be able to carefully swap the driver modules to see if the problem follows the module.

The increased frequency of the problem could be a failing component, although a failed bearing in the motor may be causing similar pain.

 

Thanks for the reply.

I already swapped the stepper driver but didn't fix the problem.

The axis moves freely when powered off.

So if it's not the driver, should be the stepper itself right?

 

Thanks!

So probably the driver, not the stepper itself?

If I test a new A4988 driver and that doesn't work I should replace the stepper, right?