RE: Core One crash/restart
I got my CORE One a couple of months ago and have only printed relatively small parts so far. Today I tried to print the TOTEM BLE Travel Case from Printables (22 × 15 cm) and ran into the same issue. I just saw your post — I hope the fix works for me too. Thanks for sharing!
What really bothers me is that Prusa hasn’t provided a solution, given how frequent this problem seems to be.
Thanks a lot to all who where involved in fixing that problem.
I ran into that issue after 6 weeks using my printer without any problems.
It was the first time I printed a plate of 190x190 mm.
The printer rebooted several times printing the first layer leaving nice blobs.I did not want to pollute my printer by milling the powder coating, so I went to a different solution which works fine.
I added two short cables to connect the motors to a definitely grounded screw.
The whole process took three hours, two hours for research and reading and one hour for fixing the problem.I have printed four of the plates mentioned above without any problem.
Thanks a lot again!Cheers
Ralf
RE: Core One crash/restart
Thanks for posting this (especially the photo). I just applied this mod to my C1L. I turned out to be easier than I expected.
My reboots were happening when I inserted or removed the smooth print sheet. So far, three sheet movements ad no reboots.
RE: Core One crash/restart
I'd love to hear from someone with a newer CORE One or especially CORE One L to see if it has been fixed in newer revisions.
It seems to be a matter of luck whether the pre-assembled printers are the stepper grounded or not. It doesn't appear to be actively checked or addressed. The Prusa instructions for the kits don't mention checking this.
On my factory-assembled Core One from May 23, 2025, the stepper motors are grounded by chance (I measured it).
RE: Core One crash/restart
I had the printer reboot in the middle of a print about three weeks before I sold my core one and divested myself of anything Prusa.
I did not have any subsequent issues but I did install a lock washer on one screw of each of the stepper motors so that it would ground to the chassis. it’s winter time here and the humidity is effectively 10% if that which will lead to more static electrical buildup.
Between that and the crappy experience with the MMU3 and any sort of manner to be able to properly use it with dry boxes, it was time just to go all Bambu, especially after the Customer Service experience with Prusa. (I had always been told that it was a good experience, but it turned out not to be a good experience. - if I’m gonna have to go through that crap, I’m might as well have a single ecosystem.)
RE: Core One crash/restart
Before trying what @ralgre suggested, I ran a few checks. It turns out the steppers weren’t grounded. I implemented a temporary fix (not as professional as @ralgre’s) just to verify whether it would solve the issue, and I wanted to share what I found.
I bought my CORE ONE+ factory-built, so I expected a professional assembly. However, I’m not sure this is acceptable — the screws labeled A and B, along with the symmetrical ones on the right side in the picture, were almost loose. This proves that @etadriver is absolutely right: Prusa did not follow its own instructions.
I kind of regret not buying the printer as a kit, like I did years ago with the MK3 and later the MK3S — amazing printer that still run smoothly and reliably.
Anyway, I took a Cat 6 cable and used one conductor, forming two small rings at the ends to connect the screw that secures the guide to the frame to the screw that holds the stepper in place. Damn! it worked — I printed the large object I wanted yesterday. Thanks again to @ralgre!
