Snapmaker Original stops mid print. Won't turn off heaters

I’ve had the SM Original since January. After minimal calibration, every print has been successful. I print approximately 30 hours per week. Love the machine and even though it’s slow, the prints look better than most.

I have the SM Original running FW 2.11 with enclosure. The door switch is disconnected. I’m using Luban 4.23.

Printed 13 hours last night with no problems. Powered the machine off this morning, made some changes to the STL, generated GCode, exported GCode file to original factory supplied USB stick and started printing again. (I always wait for the brim and first layer to complete before walking away so I know everything sticks.) Roughly ~30 minutes later I walk back into the room and the printers not moving and something is burning.

The display is still working and shows that everything is at temp (202/205 for head and 68/50 for bed), 20 minutes of file completed, 1% complete. The “stop” button is lit up but pressing it doesn’t do anything. The jog buttons work and the home button works but the heaters wont shut down and the bed and head start heating up again. The display still says that it’s working on printing even though the motors aren’t moving.

I “jogged” the head to a place not touching anything and turned the SM off via the power switch on the controller, waited a few seconds and turned it back on. After booting, it said it was still printing the same file and started heating the head and bed again - temperature was going up.

I then turned it off and unplugged it from power and then turned it back on. This time it seemed normal and returned to room temperature. I inspected the damage, bad print (of course), very blackened and burnt spot on the print where it stopped and burnt spot with visible cracking and peeling of the build plate sticker on the build plate as well as burnt build up on the tip. I cleaned the tip and flattened the build plate sticker and let it sit for 30 minutes while browsing the forums for a possible solution and then started it up again. I’m now 2 hours into the same print, same GCode on same USB stick with no problems… so far.

Please tell me there is a fix for this so I can leave my prints running over night again without a fire risk?

The only thing I can think of is, check the cable for the heated bed, especially at the ends, for damage or shorts, because it really sounds like there’s something wrong there (18C above the target temperature doesn’t sound normal, unless you had the first layer at 70C or something). I don’t know if it happens with the Original, but the Snapmaker2 models have problems with the cable getting damaged right where it connects to the bed.

Thanks for the advice. I looked at the cable ends and they look fine to me. Yes, the error occurred just after the first layer at the point the bed lowers temperature from 70 to 50 so I think the 68C was probably not out of question. Also, the nozzle was pressed against the first layer, cooking it for at least 5-10 minutes before I noticed it which could have contributed to the beds high temperature.

The second attempt finished and was fine. I set a timer to check on it every 20 minutes just in case and no problems.

That’s very strange. The Original doesn’t have a lot of smarts, and it doesn’t know how to resume after a power failure. A common problem for the v1 is slightly unstable power company or a wonky power supply making it look like it just stopped mid print, when in reality it rebooted. The only way it looks different is the progress bar is gone instead of showing some % complete.

I’ve never been able to see the Stop button and move around the menu at the same time. Either the Stop button is grayed out and unresponsive (and heaters are off), or the Controls & Settings buttons are grayed out and unresponsive (and heaters are probably on).

So to me, that sounds like either a very quick power interruption or a RAM problem. It’s definitely in a strange state that it’s not intended to be in. RAM doesn’t clear out immediately as soon as you turn it off, so it’s possible for the RAM and CPU to stay in a weird state for short periods of time. I’ll generally wait for at least a count of 10 before I power something back on after I powered it off the hard way.

This is the first time I’ve heard something like this posted to the forum, so I wouldn’t say we know enough to tell you if this is a one-off issue or a persistent problem. Your timer to check on it occasionally is a good idea, even if it turns out it was a one-time event. Lots of things can go wrong, like the filament breaking, or the head knocking the print loose from the bed. If I was going to do any overnight print again, I’d make sure it got past a few layers before turning in. That at least eliminates the sticker burning problem.

If you’d feel better with a live stream, several people have gotten the Octoprint to work with the original.