Prusa prints even though the IR sensor shows 0  

RE:

Sensor calibration for the MMU2 operation is the most delicate thing. Experience says, that even though you think you calibrated both sensors correctly, you might very well have not. There is no firmware bug that prevents MMU2 operation (it works), if you have loading/unloading issues or a misbehaving MMU2, the most likely explanation is miss-calibrated IR sensor or FINDA.

If you describe what happens exactly it might be possible to narrow it down to one of the sensors. Taking into account what you described, my bet would be on the IR sensor.

The LED mod helps diagnosing this a lot.

RE: Prusa prints even though the IR sensor shows 0

Hey, thanks for the quick reply.

I had the printer running overnight because the last 4-5 hours only had to be printed in one color (white). Unfortunately, the printer stopped extruding at some point, even though there was filament in the nozzle. The fact that the IR sensor was at 0 was probably due to the bad filament. This was a bit dented and for this reason could not push the Bondtech Gear to the side enough for the sensor to recognize it. (see photo) But why did the printer continue to print anyway? I thought when the IR sensor is at 0 it pauses the print.

I then restarted the print and changed the white filament because I suspected that it was the filament. Here, too, unfortunately, the problem is that at some point it stops extruding. It prints continuously for 4-5 hours with constant color changes and no problems. But after 1-2 hours without color change he causes problems.

What do you mean by the LED mod? Do you mean the LEDs on the MMU or on the FINDA sensor?

RE:

With MMU2 in operation FINDA is responsible for filament runout detection. The IR sensor on the extruder is only used for loading and ignored during printing.

Mod like this https://www.printables.com/model/98204-prusa-mk3s-extruder-lid-with-led-hole show the state of the sensor all times, there are several and ones for the FINDA as well. I just can’t find the right one for the MMU modified extruder, but it is on printable somewhere.