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Print start failure  

Manuel Gailberger
New Member
Print start failure

I recently bought my printer and i now want to print my first object. However there is an annoying problem occuring at the start.

First i preheated for PLA, than i loaded the filament, still no problems but now they come. After i selected the file i want to print, the printer first goes to its reference points. After that it wants to start in the left front corner. But after going straigt down, the extruder moves upwards a bit and fully to the right side where than the message comes: unload the filament. After unloading i got asked if i was able to unload it and i pressed yes. Than it said i should load the filament and asked me if it worked. I said yes and the extruder moves back to its starting position. But again after going straigt down, it went straigt up and the load/unload filament process starts again. I cant find a way out of that loop

Pls help


Posted : 07/10/2021 4:52 pm

I assume the printer is a Prusa MK3/S+.

It sound like false filament run-out detection. Try turning off filament sensor in the printer firmware.
If it "solves" the problem there is a problem with the filament sensor, either cabling or assembly (mechanical).

Have a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 07/10/2021 8:54 pm
Noble Member

It reads like your filament sensor is not working.

To check, disable the filament sensor (LCD menu) and try printing again.  If it works then go back and check your sensor installation it might just be a loose connection.


Posted : 07/10/2021 9:41 pm
Noble Member

Could also be your gcode file. It may have a filament swap at the beginning. You can open it in a text editor and look for a M600 code.

Posted : 07/10/2021 9:46 pm
Noble Member
filament sensor

I agree about the filament sensor.  just the other day my filament sensor started being problematic, for tpu only, and only for ninjaflex.  Sainsmart TPU works fine.  I ended up having to turn off the filament sensor.  Thanks to swiss_cheese for helping me diagnose this.  I took apart the extruder and looked to see if anything was messing with the filament sensor in some way.  I may end up trying to order another sensor to replace that one.  The machine isn't that old, march timeframe, but this is the first time I've had that trouble and I've printed a ton of tpu on that machine.


Posted : 09/10/2021 5:56 pm
Noble Member
I meant to add

The OP's behavior is exactly what I was seeing.  it kept acting as if there was a filament change or run-out detected.

Posted : 09/10/2021 5:59 pm