Upgraded to 3.9.0 and now it messes up my extruder every time I do a mid-print filament change!
I've been doing the same print hundreds of times over the past few weeks. It includes a pause in the G-Code at a specific point in the print where I swap over the filament and continue. I've never had a single problem doing this.
Last week I upgraded my Mk3s to 3.9.0 and now it will print the first 6 hours of the print fine, but after I change the filament when I continue the print, I get a horrendous noise from the printer, it hugely over extrudes for a few seconds, then jams up the extruder and continues to try and print with nothing coming out.
It's happened 4 times now, wasted A LOT of filament, and each time has resulted in me having to disassemble the extruder and hot end to remove the ruined filament.
I've attached 2 images of what the filament looks like once I remove it. The messed up bit at the top was sitting just above the PTFE tube around the gears, and the rest was down in the PTFE tube. It looks the same every time!
I've also attached an image to show the serious over extrusion it does when it starts printing again.
I have to reiterate, I've done this exact print with this same G-Code file on this same printer, with this same filament countless times and it's only since doing the firmware change I've been getting this. The first part of the print always works fine so it's something that is happening when re-starting a print.
At first I thought it was something to do with the temperature as the new firmware no longer automatically re-heats the hot end and bed to do filament changes etc if they have timed out, so now I manually set them to heat up again first. Still no change.
This is costing me money and valuable print time, does anyone have any suggestions? Is rolling back to an older firmware just as simple as flashing it again? Where can I download an old firmware?
Thanks
The mess in the extruder block after this happens
What the filament looks like once removed:
The over extrusion when you re-start the print (note the quality of the print up to that point is fine)
RE: Upgraded to 3.9.0 and now it messes up my extruder every time I do a mid-print filament change!
Just to note, I've just downgraded firware to 3.8.1 and the problem has vanished.
One possible thing to note is, speaking to one of the Prusa guys, they told me that 3.9.0 is much better at recognising when it's connected to Octoprint. Perhaps something in that new functionality gets confused when resuming a print via octoprint?
Either way, I'm happy to carry on on 3.8.1 but this is a problem that will definitely need resolving!