upgraded to 3.9.0 now my filament sensor doesn't work

upgraded to 3.9.0 now my filament sensor doesn't work  

Active Member

Came out this morning to find my MK2.5S printing  . . . well, thin air. Spool ran out at some point last night. 

I had flashed the firmware to the latest version (3.9.0) now apparently my filament sensor doesn't work. It says it's "on" but the auto-load doesn't work.

It's the older-style sensor I believe: tiny circuit board with an even tinier little mirror.

any ideas?

Posted : 07/09/2020 5:38 pm
Active Member

Nevermind. I answered my own question . . .  I think.

Apparently I don't have a "Mk2.5S" like I thought. I just have a regular "Mk2.5". Even though I've been running Mk2.5S firmware this whole time without issue. 

It's confusing. I originally upgraded my Mk2 a couple years ago by purchasing both the "S" and "2.5" upgrade kits at the same time. I presumed that automatically makes my printer a "Mk2.5S". But I guess it doesn't, correct?

To further confuse matters, I later went on to download and print the "B7/R3" extruder assembly (which did NOT come with the 2.5 upgrade kit that I purchased.) But this article seems to suggest that is one of the defining features of the mk2.5:


So I just flashed the mk2.5 firmware instead of the mk2.5s. Now my filament sensor works again.

It's all too confusing. But it works now. 


Posted : 07/09/2020 7:41 pm
Reputable Member

The Update from 2.5 to 2.5S is only the filament sensor. 2.5 has this "lasersensor" which was introduced also to be able to detect motion of the filament (this was never released as I know). The sensor also had problems on specific colors and materials. So there was invented the new IR-sensor which has this small steel ball and therefore it is necessary to flash a new firmware.

Best regards, Clemens

Posted : 08/09/2020 4:57 pm

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