My Mysterious SKR Mini E3 V3.0 X-Axis Driver Failures - Page 1
Forum section: electronics / repair

author: XxMandragoraxX
author_rank: Contributor
timestamp: July 03, 2025, 07:56:35 am
content: I’ve been using the BigTreeTech SKR Mini E3 V3.0 control board for a while now, and up until recently, it had been performing flawlessly. I use this board in a few custom machines that require precise and repeatable motion control. Every time I set them up, calibrate the axes, test the movements, and verify everything — they work perfectly. The motors run smoothly, homing is spot-on, and the drivers stay cool and stable.But here's where it gets strange.On three separate occasions, after leaving the machines untouched for a few days, I powered everything back on... and the X-axis stepper driver burned instanly . Not just misbehaving or glitching — completely burned out. In all three cases, the board had not been physically altered or rewired between the working state and the failure. I didn’t change firmware, I didn’t short anything, and the power supply was stable.What puzzles me most is that it’s always the same driver — the one controlling the X stepper motor. The other axes continue working just fine. At first, I assumed it might be a freak component failure, or maybe even a wiring issue on my end. But after three boards, all with the same outcome, I’m starting to suspect something deeper. Could it be a design flaw? A batch of faulty drivers from the manufacturer? Or maybe something specific in my machine’s electrical environment that only affects the X driver?I’m now on a mission to trace the root cause — testing motor wiring, checking for back EMF, probing voltage rails, and maybe even scoping the signals. But it’s frustrating and frankly a bit disheartening to watch a solid board go up in smoke without warning.If anyone else out there has experienced repeat driver failures on the board I’d love to hear your experience. This might be more than just bad luck.

author: Swake
author_rank: Frequent Contributor
timestamp: July 03, 2025, 10:13:00 am
content: Symptom: power on and immediate smoke? Not after homing or any other (automatic) move attempt?Can you confirm this is the right schematic for the board you're using (or at least it is close to it)?https://github.com/bigtreetech/BIGTREETECH-SKR-mini-E3/blob/master/hardware/BTT%20SKR%20MINI%20E3%20V3.0/Hardware/BTT%20E3%20SKR%20MINI%20V3.0_SCH.pdfAs the 4 channels seem identical from that schematic it tends to conclude that any difference must come from 'something else'. Unless there is a design issue with the board, but as it exists since 4 years now you would not be the first one noticing the failure. In my opinion a bad batch of driver chips TMC2209 is less plausible as all chips on a board would come from the same rail which would then induce random axis failure.Possibilities I think of- Different stepper.- Different load on the stepper.- Different power supply.- Different cables, or cabling method. Maybe a ground loop. Or unwanted connection between axis.- Different cooling of the driver chip.- Specific positioning of the X-axis when powering down that would induce a particular situation at power-up.- Mounting issue (screw touching some wire or PCB trace for example)Will you repair the failed boards? If not, you could sacrifice that board by connecting the X axis stepper on a different channel and see if it breaks that other channel too on power up. This would at least inform if the issue is to be researched in the board/software or more on the machine side.

author: amyk
author_rank: Super Contributor
timestamp: July 04, 2025, 03:31:17 am
content: Fromthe datasheet:QuoteIs the X axis' driver power rail closest to the PSU input than the others? Are you (or something) moving the X axis with the power off?

author: thm_w
author_rank: Super Contributor
timestamp: July 04, 2025, 11:13:46 pm
content: Quote from: amyk on July 04, 2025, 03:31:17 amIt is the closest to PSU input:https://github.com/bigtreetech/BIGTREETECH-SKR-mini-E3/blob/master/hardware/BTT%20SKR%20MINI%20E3%20V3.0/Hardware/BTT%20E3%20SKR%20MINI%20V3.0_Top.pdfSome reports of X axis failed, claimed to be overheating:https://simons.tech.blog/2020/12/24/skr-e3-mini-v1-2-tmc-error-x-axis/But that doesn't seem to match up with what OP saw.

author: amyk
author_rank: Super Contributor
timestamp: July 05, 2025, 03:19:17 am
content: Quote from: thm_w on July 04, 2025, 11:13:46 pmGood evidence. Next request is for the OP to put a scope on the voltage rail and see what the rise time (and peak voltage, if there is any ringing) is.

author: XxMandragoraxX
author_rank: Contributor
timestamp: July 07, 2025, 07:43:34 am
content: I'll try this I'll sacrifice the board to find out if the stepper motor is the problem.

author: XxMandragoraxX
author_rank: Contributor
timestamp: July 07, 2025, 07:47:42 am
content: Yes, it's quite likely that the motors move slightly before the power is fully connected. Maybe this is the problem; ill try to replic that