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X-Axis Stepper Motor DOA  

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Straight_Haste
(@straight_haste)
New Member
X-Axis Stepper Motor DOA

Finished up assembly of the kit no problems, but the printer couldn't make it past any setup.  No movement from the X-axis motor, it just vibrates when power is applied to it.  It will not rotate with or without load, assembled or out of the unit with no gear, and it will not move plugged into the a different driver (Y axis).  Customer service determined it's a faulty motor.

Prusa was great about shipping a replacement out, but it will take time to get here and I'm wondering if there is anything I can repair on this motor?  Or something that I'm missing.  The kit came with QA test sheet that listed it as OK (no idea how they tested it) and it appears visually fine.  The rotor turns freely by hand without binding on the stator, the wiring isn't crimped and both coil circuits have continuity at 6.5 ohms each.  The bearings are fine and there is no visual scoring on the rotor magnet.

I'm not sure where they are sourcing these motors, but they don't appear to be cheap Chinese motors.

Posted : 09/12/2022 3:23 pm
RandyM9
(@randym9)
Honorable Member
RE: X-Axis Stepper Motor DOA

You could try switching the X and Y connections in the Einsy board to identify if it’s the motor or the driver.

Turn off and unplug the printer, undo just the upper screw on the Einsy door, lift the door and remove it.

Carefully unplug the X and Y plugs from the Einsy board. Put a piece of tape on one of them so you don’t mix them up. Plug the Y connector into the X motor plug and vice versa with the X plug.

Gently and slowly slide the extruder to the center of the bed. Gently and slowly slide the bed to the center of its travel.

Plug in and turn on the printer. Leave the door off the Einsy board for now. Using the click wheel on next to the LCD screen, press the button and scroll to >settings >move axis:

Select >Move X - spin the wheel to the right - the bed should move towards you. Spin the wheel to the left - the bed should move away from you.

When done, press the button to go back and select > Move Y - spin the wheel to the right - the extruder should move right. Spin the wheel to the left - the extruder should move left.

Maybe Prusa support already had you do this?

Once you determine what the issue is, put the plugs back where they belong and button everything up. Don’t forget to turn off power and unplug first. Best of luck to you.

Cheers

Posted : 09/12/2022 3:53 pm
Straight_Haste
(@straight_haste)
New Member
Topic starter answered:
RE: X-Axis Stepper Motor DOA

Yessir, did that.

Posted : 09/12/2022 4:47 pm
RandyM9
(@randym9)
Honorable Member
RE: X-Axis Stepper Motor DOA

Okay, good to hear.

Most folks will tell you not to open the stepper motors because the magnetic field will be permanently altered in a negative way. If Prusa are sending you a new motor, no real reason to open it anyway. They may want it back on the RMA.

Some folks have opened the stepper motors and been able to diagnose and repair in specific instances. Search the forums for more details but I would personally be disinclined to mess with it at this point.

Cheers

Posted : 09/12/2022 5:32 pm
Straight_Haste
(@straight_haste)
New Member
Topic starter answered:
RE: X-Axis Stepper Motor DOA

Ya, I'll probably refrain from opening it up.  I've read the same about stepper motors degrading magnetism upon opening.

Posted : 09/12/2022 6:08 pm
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