To the Moons and back…

So lately you may have heard about the trend in swapping out the extruder motors on the MK3 from the stock LDO motors to the newer fancier Moons motors. Why? One of the artifacts that can be pretty gross and make out prints not look super sexy is poor linearity or moire in the print. For a long time this was thought to be an issue with the Trinamics 2130 steppers and I still believe this to be the case but only that the Trinamics steppers Stealthchop mode just doesn’t play well with certain windings or levels of back EMF from certain motors.

I know this sounds like a scary and expensive fix but there is hope on the expensive part. We don’t know all the motors that work better with the Trinamics different modes so more testing would be needing and this is where the internet hive mind can come together and test differs motors. I personally choose Moons because of their reputation as one of the best motors on the market and really all I wanted to do is see how well better motors work. I was definitely not expecting what I found out.

So the MK3 is pretty silent in normal mode but these motors are on a new level of silent. Swapping the X and Y axes results in snappier and quieter movement which was pretty astonishing. The only real benefit I saw from tech X and Y motor swaps was the snappier more precise movement. Overshoot seemed less and overall the printer was better but not nearly $80 better. Did I mention these run $36-$40 each?

I don’t recommend the X and Y motor swaps unless you really want to but I do recommend the Extruder motor swap. Why? It solves an issue that many have which is moire in the prints. Basically an angular pattern looks repeated over the entire surface of the print. If you looks closely at the two prints you’ll see one has almost an angular look to the layer lines. This is was the ECORRECTION settings were supposed to fix but overall they mostly reduced the issue or were too difficult to tell any difference. The print on the left is Moons by itself with no correction and it’s completely missing the strange unexplained lines from the print on the right. Both were using the same filament and same gcode just a different motor.

The swap isn’t going to be easy but it gives you time to do a few things. I highly recommend upgrading to the R3 extruder parts Prusa just launched so print those before doing the motor swap since we already have to dig inside and take nearly everything apart. I also recommend swapping out the not so cool spiral cable wrap with a 3/8″ braided wrap-around sleeve because it’ll put less stress on the cables. You’ll also need some proper cable to connect your motor to the Einsy board. I went with these BiPolar Stepper Motor Cables but you’ll need to do a little surgery to make them work properly.

We have our motor, we might have our new cable cover, we may even have the new R3 extruder parts, but we still need to make sure the wires are correct. If you purchases the same Yotino brand cables as I did all you have to do is swap the green wire for the red wire. You can do this simply by using a small thin blade or tweezer to lightly pull back the the little tab that hold the connecter in place for each wire. Don’t pull back too hard or it may break. My recommendation is to push the wire forward, pull the tab back slightly, and gently pull the cable out of it’s home. Do this for both the Green and Red wire. To get them back just insert and they will lock right back into place all happy and cozy. Double check and make sure the wires are in the correct order now. With the tab side facing you the order should be Red, Blue, Black, Green. Any other combination is wrong. See photos for correct orientation and color pattern before plugging anything in.

Now that you have everything ready you are ready to take apart your extruder and do all of the necessary swapping and such to upgrade from the LDO motor to the Moons motor. Good luck and may your rebuild go smoothly!


42 thoughts on “To the Moons and back…”

  1. After the wire swap on the six connector end, which way is the four end connector placed on to the einsy rambo mother board with this particular cable?

      1. Maybe edit the main text to include this bit? Would be pretty helpful I think. I was wondering about the same question.

    1. You sure can but I haven’t seen the benefit yet with doing so on mine. The machine is much quieter with the new motors but no drastic changes in print quality.

  2. Nice article, thank you for that! My extruder’s running quite hot most of the time, so I’ll definitely try a Moons out.

    Let me guess though; the 1.5A version won’t work? That one, I would actually be able to order on Amazon…

      1. I found those and was looking into ordering a bigger batch and sending them out to people who are interested as well. Amazon would offer the 1.5A version without shipping and at a much lower price though, that’s why I was hoping I’d be able to get those. But finding the specifications that the printer would still be able to handle is beyond me so far

      2. Your link is to (MS17HD2P4200) Stepper Motor
        but the Chris shows (MS17HD2P4200) Stepper Motor in the Picture.
        What would be the correct model to get for the Prusa MK3 ??


  3. Chris, Can you please call out the colours on the other end of the stepper motor cable. I have some cables that have arrived but are a different colour scheme so would love to be able to match it up properly before I stuff things up. Ta

  4. Does anyone know if linearity correction will still function properly with the moons extruder ?

  5. Completed the MOONS upgrade today on my stock extruder, it is running much cooler.

  6. May be off topic, but in moving to the R3 extruder have you had issues in trying to maintain the correct temp on the nozzle/hot end?

  7. The Amazon page for the MOONS’ motor is using one your pictures now lol you’ve probably helped make it popular. I still need to just jump in and buy it.

  8. Just wanted to drop in and say I did a R3 rebuild and decided to swap the extruder motor with a MOONS’ and you’ll have to rotate it 90 degrees clockwise if you want to use the default angled fan mount, as the plug from the motor was in the way and prevented properly mounting the part fan.

  9. Hi Chris, I end up getting the cables from a different supplier and they are colour coded different but the idea should be the same I just want to be sure how the Prusa board accepts the signals. on the ( black connector) pin 1 ( triangle icon) goes to pin 6 on stepper motor connector, pin 2 goes to pin 3, pin 3 goes to pin 4, and pin 4 goes to pin 1.

  10. So you state to replace the wrap with the 3/8 loom. The cable for the heat bed already has the loom. You are saying replace the cables to the extruder as well?

  11. Hey Chris,

    I bought the same wires as you for the motor but The order is different. The white connection facing the same as your picture is blue, red, green, black.
    The black connection with the open towards me (where it exposes the metal) is reversed. Black, green, red, blue. I can send a picture if that sounds confusing. I just want to make sure the wiring will be correct. Or if I need to send them back and look for a different cable.

    Thank you,

    1. I also bought the wires and have the same color combo as you. They must have changed manufacturing since Chris made this guide. I am going to assume it is the same swap of wires and that colors don’t really matter. Wire is wire. Its the same gauge and the same destination.

    2. Never mind! I just re-wired the ends to look like the picture provided for the cable and then wired the white end to match yours. Thank you!

      1. Can you tell me the order you have the wires in? I purchased the same cables and have the same wiring colors as you do. If I am holding the black 4 flat connector in my hand, metal side facing me, what is the order of the cables from left to right?

      2. I am trying to figure this out too. Can you let me know what color combination is for the black end on yours? My colors were different on the white end. I assumed both ends were off, so i just reversed the first and last wires as done, regardless of color. I am getting a stuttering which makes me think my order is off.

  12. Can you please post a picture or wire order for the einsy side of the cable? I ordered the same cables you have linked, but my cables look nothing like the pictures on amazon and I don’t want to mess up my board. Thank you for the excellent article, and thanks in advance for your help.

  13. Are the red and blue wires supposed to be switched on the Einsy side? Could you post a picture of the extruder wire plugged into the board? I have mine all ready to go, just don’t want to burn out something. Thank you so much for the article and testing regardless.

  14. Just so you know, the cables you linked to no longer have the wires in the same order. The cables I got go blue red green black.

  15. I’m doing the Moons upgrade for my printer, but the colors aren’t the same order on the cables I got, and at the moment my printer doesn’t actually use the motor when I try to load filament. Do you think you could tell me which pin on the Einsy board needs to be connected to which pin on the Moons motor?

  16. The print on the left has terrible print lines, which are not seen on the right. Also, there is a slight moire effect on the left, you can see it in the middle of the print, starts out looking like the top of a Z…

  17. Hello, I have attempted to change the extruder to the moons stepper.

    The Cable i bought sadly didn’t fit the einsy board so I soldered the connector of the original extruder to the new cable according to their colors and the original plug color order. (Which just seemed to be a switched blue and red wire compared with the Yonito cable) so i changed them accordingly to your description and changed the position of the blue and red color therefore my order was: Blue, Red , Black, Green

    I now turned it on and the extruder is not moving.
    Im a bit confused since i followed the guide minusculely except for the changed wires.

    Please Help!

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