Filament sensor issue  

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Cocomon
(@cocomon)
Active Member

Hi 

The filament sensor suddenly went dead. I tried the trou le shooting from the manual, doesnt work. Have attached some pics and a video. Appreciate some guidance

Posted : 09/05/2021 10:55 am
Cocomon
(@cocomon)
Active Member

Sorry video is too big but qttaching some pics. Basically on the sensor value = 1 with filament in, 0 without. I can see the magnets are correct and the ball bearing does move when i push in the filament. However sensor remains dead.

Posted : 09/05/2021 10:57 am
Cocomon
(@cocomon)
Active Member

Managed to downsize the vid

Posted : 09/05/2021 11:02 am
Baklin
(@baklin)
Reputable Member
Posted by: @cocomon

Sorry video is too big but qttaching some pics. Basically on the sensor value = 1 with filament in, 0 without. I can see the magnets are correct and the ball bearing does move when i push in the filament. However sensor remains dead.

You say you see the 1 and 0 when pushing in and removing the filament. That would indicate that the sensor is working.

Posted : 09/05/2021 1:55 pm
Baklin
(@baklin)
Reputable Member

Also the way you are testing the sensor could be a problem. Prusa advices to use a dark filament for the extruder parts as the sensor can be fooled by to much light. With the extruder apart like you have that could be a problem.

Posted : 09/05/2021 1:57 pm
Cocomon
(@cocomon)
Active Member

@baklin

Thank u. I thougj so too, but when i feed the filament in, the stepper doesnt seem to work and there is no motion at all. Is yhere someyhing else wrong other than the sensor? 

 

I did make the mistake of opening up the extruder stepper motor before, although it still worked fine after that. But after a couple print it suddenly stopped.

Posted : 09/05/2021 2:50 pm
--
 --
(@)
Illustrious Member

And the video doesn't work - at least for me. Downloaded and saw a stream of binary in the video window... lol. 

A common issue with the sensor is the flag doesn't cover the sensor or gets stuck because the screw is too tight. These were supposedly fixed in the +, but the entire contrap--- mechanism -- is Rube-Goldberg, ymmv.

 

ps: There are settings down in the menu to enable the sensor and set auto-load on or off. Have you read the handbook?

This post was modified 1 month ago by --
Posted : 09/05/2021 2:50 pm
cwbullet
(@cwbullet)
Illustrious Member

@tim-2

The video did not work for me either.  I found that if the screw is too tight, the sensor does not work well.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 09/05/2021 3:36 pm
HeneryH
(@heneryh)
Estimable Member

If your value goes from 1 to 0 and back then your sensor is working fine.

 

But, if you misstated that and it really isn't working, many of us with MK3S had problems where we had to loosen or fiddle with the sensor cap on the top of the extruder.  I, along with others, had to print a small shim to place under it to make it work well.

I read that the MK3s+ had a redesign to make it work more consistently.

Posted : 09/05/2021 4:58 pm
Baklin
(@baklin)
Reputable Member

If the sensor state changes from 0 to 1 the sensor is working.

Have you checked in the menu if auto load is enabled? (filamentsensor: On and f autoload: ON)

See page 34 in the handbook.

Posted : 09/05/2021 7:16 pm
Cocomon
(@cocomon)
Active Member

@tim-2

thank you. the filament sensor indeed does pull a 1 & 0, so appears it should be working. will try the screws again. thanks

 

Posted : 10/05/2021 7:51 am
Cocomon
(@cocomon)
Active Member

@baklin

yes sir, done that. will give the screws a try when i head back. thanks

Posted : 10/05/2021 7:52 am
HeneryH
(@heneryh)
Estimable Member

I'm confused now.  What exactly is not working?

Posted : 11/05/2021 8:44 pm
cwbullet
(@cwbullet)
Illustrious Member

@heneryh

That makes two of us.  Maybe we need to start fresh.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 11/05/2021 9:29 pm
--
 --
(@)
Illustrious Member

And then there's this new tidbit in the latest firmware notes that the filament sensor had a few bugs and now autoload is disabled [prevented] when you have the menu for sensor status open. So if it is changing states and not working -- well - that is now normal and expected. 

Posted : 11/05/2021 9:35 pm
Cocomon
(@cocomon)
Active Member

@heneryh

Sorry been flat out. Well from all the guidance given, i suspect 2 issues: 

1. Filament sensor not working (from my checks, it is working but somehow the extruder motor is not moving when the filament is fed in. no sound at all, filament doesnt move)

2. improperly assembled nozzle and heatsink, resulting in small reservoir of filament on the heatblock for longer, higher resolution prints.

intend to change the nozzle and reassemble to test again. keep all posted. its very frustrating for me as i am quite lacking in the technical or engineering aspect, but will read along and give it a good go! thanks guys. 

Posted : 17/05/2021 3:10 am
Cocomon
(@cocomon)
Active Member

@heneryh

Sorry been flat out. Well from all the guidance given, i suspect 2 issues: 

1. Filament sensor not working (from my checks, it is working but somehow the extruder motor is not moving when the filament is fed in. no sound at all, filament doesnt move)

2. improperly assembled nozzle and heatsink, resulting in small reservoir of filament on the heatblock for longer, higher resolution prints.

intend to change the nozzle and reassemble to test again. keep all posted. its very frustrating for me as i am quite lacking in the technical or engineering aspect, but will read along and give it a good go! thanks guys. 

Posted : 17/05/2021 3:11 am
HeneryH
(@heneryh)
Estimable Member
Posted by: @cocomon

 

1. Filament sensor not working (from my checks, it is working but somehow the extruder motor is not moving when the filament is fed in. no sound at all, filament doesnt move)

Your filament sensor IS working.  You might have a problem elsewhere but it isn't your sensor.  You should stop saying it is not working.  It is.

Posted : 17/05/2021 3:21 am
cwbullet
(@cwbullet)
Illustrious Member

@cocomon

This problem is either firmware or slicer.  It appears that the sensor is fine.  I can't think of another piece of hardware that would do this.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 17/05/2021 3:32 am
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