RE: Mk 3.9 with MK4 Z Axis motors.
One thing I AM sure about though - my MK3.9 with LDO 0.9° steppers isn't as whisper quiet as my MK4.
RE: Mk 3.9 with MK4 Z Axis motors.
Only one pair of your wires was reversed. I got my motors from eBay and so I looked at the data sheet for the motors for the correct wiring. There are two separate coils in the stepper, each with a positive and negative terminal. Your had one backward from the data sheet. The other was correct.
RE: Mk 3.9 with MK4 Z Axis motors.
Also, regarding noise, I only hear little swishes from the move of the Axis'. No real motor noise at all. Can you take a video of yours. I think my printer is almost musical, the sounds are so pleasing.
RE: Mk 3.9 with MK4 Z Axis motors.
Only one pair of your wires was reversed. I got my motors from eBay and so I looked at the data sheet for the motors for the correct wiring. There are two separate coils in the stepper, each with a positive and negative terminal. Your had one backward from the data sheet. The other was correct.
Yeah, I'm losing track now. In the end, I've pinned mine exactly as per your photo (although you haven't explicitly explained which way round your dupont connector goes into the Prusa adapter - I'm assuming you matched the wire colours, rather than being flipped), and I'm getting exactly the same result. So somehow my earlier wiring was equally correct.
I still have my doubts about the VFA comparison between the MK4 and the MK3.9 with 0.9° steppers, and the sound is definitely not as smooth.
RE: Mk 3.9 with MK4 Z Axis motors.
Yes. I matched colors with the adapter. It's possible there is enough logic in teh Buddy board to poll the stepper and internally correct any wiring mismatch between the pairs during calibration.
Just saw you newest image and it does indeed seem the VFAs have improved on the new steppers.
RE: Mk 3.9 with MK4 Z Axis motors.
While I had the printer out on my bench, pondering why it's noisier than my Mk4, I noticed that moving the x-carriage back and forth along the x-axis by hand felt quite rough. Compared it to the MK4, and it's definitely rougher. The y-axis on both machines felt smooth though. After confirming the belt tension was ok, I then disconnected the belt to see if the roughness was caused by the motor or the x-carriage bearings. Perfectly smooth without the motor attached.
So since I have five of these motors, I swapped the x-motor for a fresh one - much easier with these motors that have a plug at the motor end. Now the x-carriage moves just as smoothly as my MK4. I swapped the y-axis motor for a fresh one as well for good measure, because I figured it was just as likely that my experiments with the wiring could have damaged it, rather than being faulty out of the box.
It's now very much quieter, although it's still not as silky smooth as my MK4 for some reason. But most importantly, my test print is now indistinguishable from the MK4 version.
RE: Mk 3.9 with MK4 Z Axis motors.
Awesome! Persistence for the win! Now you have 2 MK4. When I rebuilt mine I used genuine Misumi bearings, brand new and lubed according to prusa recommendation. They are noticeably nicer sounding than the Prusa supplied generics I had before. Motors are quiet and all I hear is the sliding of the axis bearings on the rods.
RE:
My MK3S+ from November 2021 came with Misumi bearings originally. I virtually stopped using it once the MK4 arrived in June 2023 (hence the decision to buy the MK3.9 kit). When I stripped it down it had 92 days and 7.6km of filament on the clock. In that time I hadn't serviced the bearings at all, but for the MK3.9 build I cleaned and relubricated them, and they all felt nice and smooth. I don't think the noise is coming from the bearings. My MK4 kit came with generic bearings, and they feel every bit as good as the Misumis.
I do think the extra noise is from the LDO steppers. I run both my printers side by side inside Prusa enclosures, and when I run the MK3.9 on it's own it doesn't sound too bad. But when I run them both at the same time, the MK3.9 is the one I can hear - the MK4 is virtually silent next to it, with the extruder and the bed just swishing back and forth. I'm definitely not going to go to the lengths of swapping the MK4 motors into the MK3.9 just to diagnose the noise, but when the genuine MK4 motors appear in Prusa's Eshop I may well be tempted to add a couple to a parts/filament order.
RE: Mk 3.9 with MK4 Z Axis motors.
Thanks to both myself and our kid being sick this 3s-> 3.9 got delayed. But that let the wire adapters get here and so last night my MK4 came to life thanks to the motor swap
booted, ran tests (used the dental tool tip for the y axis test issue) updated firmware and it always registered as MK4 fun experiment
now to attempt some shorter custom wires like mentioned as the clickmate precrimped ones got here too
RE: Mk 3.9 with MK4 Z Axis motors.
Here’s mine with the LDO motors. Printing almost as fast as my X1C and very quiet and pleasant sounding. Video makes it seem louder than it is but fans and bearings are louder than the motors.
RE: Mk 3.9 with MK4 Z Axis motors.
I guess video was too big. Maybe this one will work
RE: Mk 3.9 with MK4 Z Axis motors.
RE:
That's pretty much how my MK4 sounds, but my MK3.9 with LDO steppers (MK 3.99?) is noisier. I'm starting to think it may be variability between individual motors. Correct me if I'm wrong, but weren't there a few early complaints about MK4 noise, and did I read somewhere that Prusa now test every motor before shipping kits/printers? And isn't the new XL phase stepping feature partly about dealing with individual motor variance?
I suspect the LDO motors I've bought just aren't as good as the individually tested ones that Prusa will supply, whereas other people have been luckier with their LDO motors.
I'm keeping an eye on the Eshop, and will likely buy Prusa motors when they become available, but since the printer works very nicely already, I wonder how far off the whole accelerometer/phase stepping approach is for the MK4 - it would be interesting to wait, to see what it could do with my noisy LDO motors.
RE: Mk 3.9 with MK4 Z Axis motors.
True. There were some noisy motors in the initial batches. Not sure of the motor resonance reduction will make it's way to the MK4, but my Dad's XL is so noisy you can hear it through walls! It's insane and it needed the new feature for sure. He hasn't done the resonance compensation firmware yet because it's alpha. Also, saw someone has managed to get an accelerometer to work on a MK4 and is planning on working with some other folks to make a kit project for it. I suspect PRUSA will respond with their own, and that will make ANY .9 steppers a reasonable option. For now, I think the stock IS profiles work amazingly with these LDO motors. Annoying that PRUSA won't just sell theirs, but I know they are trying to keep the FYSETC and other clones from hitting the market too soon. Eventually that will happen though, and will likely hurt PRUSA sales.
RE: Mk 3.9 with MK4 Z Axis motors.
Yeah, I've seen that accelerometer development - impressive work. I don't remember the details, but isn't he running code that he's found in the firmware? If so, that would suggest that Prusa are clearly working on making the IS profile user-configurable, so will likely have their own parts available eventually. It's a short step from there to phase stepping I'd have thought. I can hope, anyway 🙂
RE: Mk 3.9 with MK4 Z Axis motors.
I also ordered the same motors as you and I am very satisfied mk3,9 is now mk4 where do you buy the molex click-mate cable connectors and I can't find the pins for them?
RE: Mk 3.9 with MK4 Z Axis motors.
I need a new right stepper motor for mk4, can you recommend a replacement??
RE: Mk 3.9 with MK4 Z Axis motors.
I need a new right stepper motor for mk4, can you recommend a replacement??
If you mean the right Z-axis, you can just get one in the Prusa store https://www.prusa3d.com/en/product/stepper-motor-z-axis-right-2/
Also noticed they have the MK4 X and Y axis stepper motors in stock now, so theoretically all the MK3.9s could move on up to MK4s with a motor swap, and no wiring change out required.
RE: Mk 3.9 with MK4 Z Axis motors.
Thank you for the tips. This worked! Just a small item on the Y axis left rod in the front allowed the Y axis test to pass.
I "factory reset" the settings of my printer and went through all the tests with my new MK4 z axis motors... it still shows up as 3.9 though. What am I doing wrong?
RE: Mk 3.9 with MK4 Z Axis motors.
Never mind, I was dumb. I thought I just needed new Z motors to go from 3.9->4, but I also need new X and Y motors 😛
Time to pay for more shipping and duties! 🙁