[Solved] X stepper missing steps ?  

X stepper missing steps ?

Hello,

All of a sudden, my X stepper motor seems to be «missing » steps. When the hotend is moving, there are visible, around half of a second, stops in the movement where there should not be.

Here is an image of an aborted print of the well-known « stress-free calibration » model ( https://www.printables.com/fr/model/251587-stress-free-first-layer-calibration-in-less-than-5).

The left-side teeth should be aligned, and they are not : the topmost three and the last one are like 1mm short. The filling, on the bottom, is also too short, with the visible empty square just aside the first indent, and empty space near the second tooth.

This second image is a close up of the filling's surface.

There is one quite visible line of material, on the right, where the movement of the hotend did « stop and restart » (and a few others partial lines, less visible and shorter, on the left and middle of the image).

Any idea about what could be the cause of this defect and how to correct it ? Is the stepper-motor dead or dying ? Or could it be stg else ?

Thanks.