Ooozair

I'm sharing the same suspicion, it's the only thing I did that really changed any states within the system. If it happens again, I'll cycle the brick first and see if that helps.

Hey everyone! Sorry about the seemingly late replies on my part, since I'm a new forum user the mods have to accept all my posts manually. Good news- got it fixed! But, still not sure exactly what was causing it. Here's what I did. Under the guidance of Ultimaker US Support (thanks Spencer!) I got some help. Turns out I wasn't under warranty anyways, haha. I took a look at the white main board. Nothing looked amiss. All the cables were seated properly, all the locking clips were engaged. No physical damage on the board or anything. Before the next test, Support did have me unplug the power brick from the machine and the wall, and see how long the LED stayed on. It remained on for well over a full minute. I had the idea of plugging the X/Y motors into the Z port, and running "Lower Bed" to see if the motors themselves worked properly when plugged into the Z port. The plugs were tough to un-plug, they were definitely seated properly to begin with. When in the Z port, both X and Y stepper motors were driven like normal. So I thought it could be the X and Y drivers. Then, I plugged the Z motor into the X then Y port, and used "Home Head" to see if the Z motor would be driven smoothly. It was! So, it wasn't the motors themselves, nor was it the drivers. I went ahead and plugged all the motors back into the correct ports, and... it worked? No jitters, no stutters, everything moving smooth. A bit confused here, nothing fundamentally changed, but the problem disappeared as quick as it appeared in the first place. I'll keep an eye on the machine during the next few test prints. So technically, all the steps I did from problem to solution were: Factory Reset >> Power Supply LED Test >> Unplug all motors >> Drive X motor with Z port>> Drive Y motor with Z port >> Drive Z motor with X port >> Drive Z motor with Y port >> Return all motors to correct ports >> Motors now move smoothly. Tested using Home Head and Manual Bed Leveling Thanks for all the help guys, this community has excellent support.

Thank you all for the speedy replies! Where should I be probing to measure the appropriate voltage? Take the bottom board cover off and probe off the PCB/Arduino itself? 1,3,4) Nope, didn't mess with any of that. I have in the past specified jerk and acceleration settings for specific prints via Cura, but nothing within the hardware itself. 2 and 5) Well, the Z axis motor and both bowden extrusion motors can spin at speed with no problem. Bed raise and lower works fine, as well as material load and unload. If it was the power supply or the MC clock, I imagine those other motors would also be affected? I felt around and re-firmed every connection I could see. The stepper motors seem to be connected with a small junction at the bottom, but light wiggling couldn't remove the cables and so I'm not sure if they're meant to be unplugged. Without removing the board cover those are the only plugs I have access to. Cables all seem intact, no weird routing inconsistencies or pinch points. Just did a reset to factory settings, problem persists. EDIT: Wording

Hey community, My UM3's stepper motors are shaking and making an awful grinding sound. Sometimes the Y axis even travels the wrong direction. The printer completed a print just fine, and when I began the next print, this problem began occurring. When the problem first occurred, it was only when the Y axis moved. After troubleshooting and watching it a few times, it started happening on both axis. Now, it consistently occurs on any axis movement (except Z, of course). Never had any similar problems thus far. Here's a video of the issue. I took the print head off to eliminate the possibility that it's something to do with the linear bearings. (Sorry about the vertical camera) In the video I'm running the "home head" command via the regular menus. I run it three times, and in the final try you can see the motor move the wrong direction too. What I know: The limit switches are good (tested those by triggering them manually) No mechanical contact on rods or blocks Stock printer (no mods or changes, except some new print cores) Belts are tight, no slipping. Moving rods manually is smooth and easy. Shown in video. Firmware 4.3.2.20180308 Hardware type ID: 9066 The printer is kept relatively cool (it's in the company's server room which is kept nice and cold. Window and blinds stay closed always), but I can't verify the temperature of the stepper drivers on the board of course. I suspect the stepper drivers are bad. This sounds like what happens when I hook up a stepper motor incorrectly on a breadboard. But what would cause them to go bad? I'm not printing excessively fast or anything (typically ~80mm/s). Why did it start with one motor, but then occur on both after a few trial runs? Any ideas here? The printer is under warranty, and I don't want to do anything that will void the warranty (dunno if opening it up and inspecting the board is allowed or not). Anything I can do before I just send it back under warranty? Hoping to save some time by seeking suggestions. Thanks everyone.