Trouble with first prints
My son and I just finished building our MK3s last night (woo hoo!) I thought there would be some files on the SD card but there were none. So we downloaded an STL from Thingaverse, ran it through Slic3r and put the gcode file on the SD card. We selected the file in the printer and tried to print. The MK3s went through the calibration process and warmup as expected, but then stopped and gave this message:
"Please press knob to unload filament." then when knob pressed "Please pull out filament immediately."
We do these things and are back to square one, it didn't print. Trying again we get the same result.
I tried again with a Benchy file from Thingaverse, going through the same process and it worked fine. In fact the print came out remarkably beautiful. However, we have not gotten it to work with any other files we have tried. Any idea what the issue might be?
RE: Trouble with first prints
Update, we disabled the filament sensor and it prints. Not sure why it would work for one and not for all. Subsequent tests with Benchy didn't work until filament sensor was disabled. Any guidance to resolve would be appreciated.
RE: Trouble with first prints
I do not have a mk3s (yet) so I can't offer specifics but I have read that some folks need to calibrate their sensor positioning a bit; I believe this entails viewing the sensor value in the support menu and at the same time making minor adjustments to the lever and positioning until it reliably reads 1 with filament inserted and 0 without. If it's borderline then you're likely to get false readings like this if you have a bit of filament that is slightly undersized, for example.
Here are some basics that may help:
https://help.prusa3d.com/article/43mduc4zdn-filament-change-prompted-at-the-beginning-of-the-print
RE: Trouble with first prints
Wow - my MK3 SD card had a number of examples, sliced into gcode and raw STL files. I'd post but it's hundreds of megs.
Samples are here: https://www.prusa3d.com/printable-3d-models/
If the links above don't help. A few folk have found their sensor is stuck on or off due to the lever screw being too tight; and the flag on the lever not actually moving far enough into the IR path to trigger it. One said he had to trim some flashing off the flag because it was causing an intermittent on-off (a bit like what you describe).
RE: Trouble with first prints
Did you get this fixed? I had my sensor plugged into the wrong row of pins on the board when I had this same problem. A tip is not to do the wire connections at 2 am! I just called it a night and came back in the morning to re-check my connections when I found out what I did.
RE: Trouble with first prints
Thanks for all the great information! Have not tried the sensor adjustment yet as we have had too much fun printing things. 😊 Last night I spoke to one of our FIRST Robotics team seniors who has a MK3 and he said the sensor was a pretty common problem. Hopefully we can get some down time today to work on it. When we do I'll report back. We are loving the printer though, and my son is over the moon happy with it. He even printed out a Mother's Day gift for mom.
RE: Trouble with first prints
OK, I've gone through the steps that @vintagepc linked to here: https://help.prusa3d.com/article/43mduc4zdn-filament-change-prompted-at-the-beginning-of-the-print#_ga=2.201118890.569341401.1557551203-1553589764.1557551203
Everything was set up properly mechanically so unfortunately the problem remains. I also unplugged and replugged both ends of the wiring to double check that was correct (it was). Stuck for now, but I have emailed Prusa in case there is any additional support they can provide. The only other thing I can think of is a faulty IR sensor. Otherwise I don't know what the issue would be. Meanwhile we have the IR sensor off and continuing to print.