Hi. I’ve done something stupid and I think I’ve burned out the extruder stepper driver output on the controller board. There is no signal on that pin and the extruder won’t extrude.
What a plum.
Unless I’m monumentally lucky and it’s just a through-hole transistor/FET, I be needing a new board.
How much and how fast, please…?
Ed.
Best reach out to support@snapmaker.com. Want to say they are $150-ish for a new controller - they don’t sell components, only assemblies 
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There is no FET on that pin, it’s a signal from the mcu to the stepper driver in the toolhead.
Support has a special firmware version that will redirect all of the controls for the toolhead to the next port down. A copy of it is posted here: Laser toolhead went BANG! - #30 by mjlowe75
That was EXACTLY what I was hoping to be able to do actually given the open source nature and the fact that MCUs almost always have spare outputs. I guess that patch would need to be applied after every firmware update?
Thank you for your advice. I might try it to fully diagnose the issue.
I fully accept that it’s not a warranty job. I’m a competent hacker, but I made a stupid mistake and threw 12v down that wire…
Yea, something on my radar, but low on the priority list, is making a git patch that could be applied to the current firmware to redirect the outputs. If you want to give that a shot I’ll share what I know. All of the pins are in the headers, and it’s relatively straightforward to trace the assignments - might be easiest to trace the wires on the board back to the mcu and write down the pin assignments.
I need to open the controller back up and flash it with a debugger (slightly broke the serial buffer playing with it), could trace the pins then.
I do know the current firmware on github is not the current firmware binary they posted - they annoyingly are dual maintaining now with a private repository before the alleged cutover in the future where it will be solely the public github repo. So any patches won’t have the latest fixes from the forum binary.
I think its appropriate to credit SnapMaker here - I’m dealing with a lady called Tracy who has been both responsive and helpful. At the end of the day I’m some hacky type who’s accidentally “dielectrically tested” one of the MCU outputs at 12v, and it failed, probably because it runs at 3v3 or so, and I’m running to SnapMaker crying about it, so I’m pretty grateful for their help. Of course they will make a sale out of it so $$, but still I would expect some manufacturers to be upset that I have hacked about with their product. Anyway, plus points for SnapMaker and a thank you to Tracy.
It seems I may be able to get the board repaired (replaced, surely!) in the UK, so… cool!
Ed.
P.S. I did try the binary to biff the output addresses on one, but it didn’t solve the problem - I may have done a little more than just overvolt/overcurrent one output… My PSU didn’t show a current surge, but its quite a chunky PSU capable of about 10-15A and I’d imagine one of those microscopic bridgewires inside the MCU is probably only good for maybe 10mA, so I could have overcurrented it without my PSU realising. One place I briefly worked at had a failure analysis lab where they could etch the top off the chip and then do microscopy to work out what went wrong. Still, at GBP100 for the whole board…!
Hello, where you ever able to get a new controller, I’ve reached out to snapmaker support and sales 6 times with no response?