Printing stalls without any indication of an error
Almost 8 hours into a 10-hour print, my MKS3+ stopped making progress. The head simply stopped moving. Nothing was being extruded. One of the fans (I believe it's the angled one on the front of the hot end) seemed to be switching between two speeds every few seconds.
There were no flaws in the print up to that point. No error messages on the display. The info screen showed the estimated time remaining and that the nozzle and bed were at the correct temperatures. There was plenty of filament left and the spool could spin freely.
I was able to navigate through the menus, but the machine responded very slowly, sometimes taking a second or more to scroll down a single line in the menu. I chose to pause the print, which moved the head away and allowed the temperatures to drop. Next I resumed the print. After reheating, the head resumed to where it had left off and just sat there. The front fan speed continued to alternate between a low and high speed every few seconds.
I aborted the print job, and everything seemed fine.
I've printed this particular model five or six times in the past couple months, and it had always worked well. I guessed that the SD card has somehow been corrupted--ESD? But wouldn't that have been detected when the printer scans the gcode file at the beginning of the print job? Also, PrusaSlicer G-code Viewer 2.5.2 can render the entire object directly from the SD card.
Other ideas?
RE: Printing stalls without any indication of an error
A second attempt failed at exactly the same place.
I resliced the model. From the last failure, I new the Z height, so I was able to inspect the gcode for the layer that failed. Nothing seemed suspicious. I exported the newly sliced gcode to disc and compared it to the gcode on the SD card. They were identical.
After some more poking around, the PC started reported filesystem errors on the SD card. The Windows repair tool said the errors were unrepairable. The SD card was not very old, and had not been written to in months. In fact, the most recent file was the one I had printed successfully several times before. Nevertheless, I've copied the fresh gcode onto a brand new SD card and am attempting the print again. I expect it will work correctly this time.