Hi all,
long story - tl;dr: I think my toolhead port polyfuses tripped, but I also clearly had the smell of burnt electronics from the controller - I always thought that polyfuses trip “gracefully”, and no smell comes out. Am I wrong?
Here’s what happened:
I changed my A350 from 3D print configuration to 10W laser. I do this always with machine completely switched off, I double and triple check that the toolhead cable is plugged in correctly, and I’m 100% sure that I used the correct screws for the toolhead, not too long ones.
I started the machine, and it booted up just fine, but I found that the start screen did not list all the connected items. Where it usually lists enclosure, stop button and toolhead, there was an empty space. I moved to the control screen, and I could switch on enclosure lights and fan, but the rails would not move, homing failed. I pressed the stop button for a test, and as usual, the machine went “off” with the according message on the screen. I power-cycled to see if a reboot fixes things, but, no, same situation. So I opened the enclosure to see what’s wrong and was immediately greeted by the unmistakable smell of burnt electronics and thought: Damn!
Since no fresh magic smoke was visible (not sure if there had been any at all) I thought: Well damage done, look what’s wrong. The rails clearly had power, they emitted the typical hissing noise at rest, and were impossible to move, the steppers clearly engaged. The smell was emanating from the controller box. I unplugged toolhead and one axis after the other, trying to get things moving after each step, but to no avail, no axis movement. So I shut everything off, unmounted the controller, and could clearly smell the bad smell from near the toolhead port. Unfortunately I did not have a small enough hex driver, so I could not open the controller (yet). So I thought: Perhaps the logs tell me what is broken. Put everything together with the goal to export the logs to an USB stick. I booted the machine and - lo and behold - the start screen listed all items! And what’s more: Machine moved! And what’s even more: I successfully did the two laser jobs I had on my list!
So now I’m confused - the error indicates to me that due to whatever reason the polyfuses of the toolhead port tripped. While I did my initial troubleshooting, they did not yet reset themselves (this can indeed take minutes). When I reassembled everything in the end, they had in the meantime reset themselves (i.e. cooled down enough) and everything was back to OK. I guess I would have left it at that if not for the smell… To my understanding, polyfuses are PTCs that quickly go from lo-resistance to very-high-resistance, in fractions of a second, and they should not emit the smell of burnt electronics (I assume…). But I never had tripped polyfuses before - perhaps I’m wrong?
And of course the question remains: What tripped them in the first place? But I guess that’s another question.
Now with the machine working again, I tried to boot it up with no toolhead attached. And what is the same is that the start screen is devoid of any listed items, although enclosure and stop button are attached. Opposed to the error-situation however, I can move the rails with no toolhead attached (using the control screen). That adds to my suspicion that more than just polyfuses went wrong…
I will acquire a matching hex driver near future and report what I can see inside the controller, but in the meantime any ideas and hints are welcome!
Thanks
Hauke
