No Autoload, but air printing on second print.
Built my i3Mk3S yesterday. It autoloaded filament just fine, ran the Z calibration prints till it seemed right, printed a pretty good frog. Unloaded the filament. Today, sliced a model on PrusaSlicer, brought it to the machine, told it to run (forgot to load filament), and it warmed up, ran through its autolevel, never complained about the lack of filament, and started printing air. I wasn't sure what to expect - whether it would preheat then ask for filament, or what, so I waited through till it started 'printing'. So, having cancelled, I tried to get it to autoload the filament. It said "Autoload is active" and told me to press the knob and insert the filament. I did so. Nothing. No extruder motion, no nothing. I tried different order and timing to the filament insertion versus the clicking the button. Nothing.
I turned it off and back on again. I tried autoload first thing. It gave me the same message. Notably, it was not even preheating to accept filament. I tried running preheat first, waiting till it was up to temp, and then telling it to autoload. No dice. Same message. No extruder movement.
Since (unlike some printers) I don't immediately see a manual motor control feature apart from Z, I didn't see a way to run the extruder by hand to hand-load it. So I started my print again, and when it started running the extruder to try to print, I inserted the filament, and it accepted it and slowly cranked it through, starting to actually print a ways into the bottom layer infill. Cancelled out, started the print again, and it's going fine.
But as far as I know the problem isn't solved. It'll be a few hours before the current print is done and I can try again. Anyone know what's up? Seems like it's not really sensing whether or not the filament is there, but believing it is, maybe? I see some other related threads here, but haven't found any with precisely the same issue and steps.
Check the filament sensor status in the lcd menu with filament in and removed. The status should change when inserted or not. The filament sensor is one of the most finicky bits of the mk3s, it has be done perfectly to be reliable and often a thin shim is needed. There are literally loads of threads about it here.
I will figure out how to check that when my current print is done and read up on filament sensor adjustments. I have seen some of those threads. Thanks.
Did you do the assembly step that tells you to check the '0' and '1' responses of the filament sensor? I know it was an assembly step back when I built mine.
It's also possible to disable the sensor via the front panel. It may be disabled for some reason.
I do not see that step. The description of the Self Test says that it tests the Autofeed sensor but it doesn't ask you to pull the filament out or put it in during that test, so it's not actually testing known quantities. I will look to see if it's disabled, but since the message I'm getting says autoload is active, I don't see how that makes sense.
EDIT: yes, filament sensor On, Autoload On