5.1.0 Bug - Printer Hangs when starting multi-color print
This issue was independently discovered by both myself and another user who posted about it on YouTube. We both were printing in nearly identical ways, so it might be a bug that is very particular to a specific use case.
We both were printing multi-material prints on our MK4's, but with a virtual MMU (manual color changes). So we tell PrusaSlicer that we have multiple extruders, and use a custom Tool Change GCode to call M600. The other guy didn't use a wipe tower, I did, seems irrelevant either way.
The files were exported as ascii gcode, not the new binary, and placed on the USB. Then we started the print on the printer. As soon as you start the print, it hangs on a black screen, no matter how long you wait it just stays there. If you pull the USB stick out, the printer jumps back to the home screen, so it's not completely frozen.
We're both using PrusaSlicer 2.7.0 final and firmware 5.1.0 final.
I found a workaround, if I started the print via Prusa Link it would actually print, though Prusa Link would hang shortly after starting it, yet the print finishes okay.
The other guy changed to using binary and starting via Prusa Link, and he says that is working great for him. I've not tried binary, and I don't think he's tried binary starting from the printer, so it's unclear if binary solves anything, but definitely using Prusa Link solves part of the issue.
Note that we've both been printing successfully with a virtual MMU for a long time, and our process hasn't changed, so it was either the upgrade to PrusaSlicer 2.7.0 or firmware 5.1.0, or the combo, that introduces the issue.
Paul
RE: 5.1.0 Bug - Printer Hangs when starting multi-color print
Here's a link to the YouTube clip showing the issue:
RE: 5.1.0 Bug - Printer Hangs when starting multi-color print
I can confirm this with 2.7.0/5.1.0 while I'm currently tinkering with color changes. The MK4 will start these print jobs only via Prusa Link.
RE:
Yes, there is at least two other threads on this topic, including this one, https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk4-how-do-i-print-this-printing-help/single-extruder-mm-print-wont-start/#post-686787
In my experience, binary gcode also needs to be started from PrusaLink.
RE: 5.1.0 Bug - Printer Hangs when starting multi-color print
RE: 5.1.0 Bug - Printer Hangs when starting multi-color print
Check that the connection is working - i.e. USB cable, Wi-Fi, Bluetooth, etc. Try printing from another device. This helps to identify if the problem is the printer or the client. If you've tried all the above and it's still not working, uninstall and reinstall the printer software and drivers.
RE: 5.1.0 Bug - Printer Hangs when starting multi-color print
Weirdly, it has no problem multi-color printing using Octoprint. 5.1.0 / 2.7.0.
RE: 5.1.0 Bug - Printer Hangs when starting multi-color print
Not sure what you are replying to. Nothing of what you suggest has anything to do with not being able to start a multi-extruder print from the printer menu.
Check that the connection is working - i.e. USB cable, Wi-Fi, Bluetooth, etc. Try printing from another device. This helps to identify if the problem is the printer or the client. If you've tried all the above and it's still not working, uninstall and reinstall the printer software and drivers.