Constant unloading and loading of filament  

RE: Constant unloading and loading of filament

I did the MK3 to the Mk3s upgrade this weekend and have that same problem as started above by office-3.  I was bale to turn off the F. Sensor and load the filament and run the print without a problem.

I'm not sure how to proceed with the trouble shooting.

I have taken the filament cover off and the new sensor and inspected the movement of the FS- Lever and making sure the flag for the sensor in-tacked.

During unload the printer beeps so I'm assuming the sensor is working?

Any help would be appreciated.

Regards, John

RE: Constant unloading and loading of filament

SO, This evening I though that I should look at the IR sensor again using the control panel going to SUPPORT>SENSOR>IR and noticed that the sensor was at "one" and never changed when I inserted a filiment into the head and remove it

I then  removed the  filiment cover and removed the IR sensor once the screw was loose the control panel changed to "0",  I the placed a card board into the sensor gap and the State hanged to 1 (meaning the sensor is working).

Next I inspected the FS-Lever it looked OK not Burrs or loose plastic and the lever was moving freely. I then re-installed the sensor PCBA and tighten the screw, then installed the filiment and the "0" when to "1" but when I removed the filiment the lever was stuck on "1". Again I loosen the screw on the sensor and the and lifted it up and the sensor on the control panel went to "0". after playing with the screw tightness and not getting anywhere,  I decided to  shim the rear of the sensor (folded a small paper and install it between the plastic housing and the sensor. I did this 3 times for a total of 3 folds. During each fold I install the filiment and remove it to see if the spacer helped, on the 3rd fold the filiment was installed and removed with the with the correct "0" and "1"control panel state. put every thing back together making sure the sensor was still working by install and removing a filiment and watching the control panel state "0" to "1"

I then ran a print without any  problems for the first time without and issues  since if finished the upgrade. No more "Please press knob to unload the filament" message!

https://1drv.ms/u/s!Av5xjLH6iZ_pmO5x2cHTzDi_oRllpA

john

RE: Constant unloading and loading of filament

I had this same problem.  It turns out that my IR sensor wasn’t firmly connected at the Rambo board AND I needed to put a small spacer in.  I used a small piece of a zip tie tip, since I had plenty of those around.

RE: Constant unloading and loading of filament

I also had a similar problem and came up with this 0.5 mm spacer to go under the IR Sensor, which solves the problem for me: https://www.prusaprinters.org/prints/8624-mk3s-ir-sensor-spacer-05-mm

RE: Constant unloading and loading of filament

 Where do you put this part? Can you take a photo before and after please. I'm a beginner. 

RE: Constant unloading and loading of filament

You cannot really see it in a photo, as it goes directly below the IR-Sensor and is fully covered by it. Take a look at Step 21 of the E-Axis-Assembly manual:

https://manual.prusa3d.com/Guide/5.+E-axis+assembly/1055?lang=en

Just place the spacer under the sensor, it lines right up with the part on which the sensor is fixed ;-).

RE: Constant unloading and loading of filament

@armer_geddon

Thank you very much for this, I needed two of them for mine to work but now the issue is solved!

Community work makes magic work 🙂

RE: Constant unloading and loading of filament

This may be testing your memory, but just wondering why adding a spacer solved your issue?  I currently have this constant load/unload issue, but only when using transparent, flexible TPU.  I'm now wondering if the flexibility of the TPU is causing it to be squeezed when entering the area that pushes the little arm that triggers the filament IR sensor?  So I'm looking for any solution I can find!