1→5 tool upgrade: Filament Sensor Fail on one Tool Head - Assembly and first prints troubleshooting https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/ Prusa3D Forum Discussion Board en-US Thu, 11 Jun 2026 01:07:52 +0000 wpForo 60 RE: 1→5 tool upgrade: Filament Sensor Fail on one Tool Head https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701237 Sun, 25 Feb 2024 09:21:37 +0000 Guys, 
can we please keep to the subject matter and the ethos of a support forum, 

If a user comment upsets you, could you please move on, 
If a comment or subject upsets you a lot, could you please report the post and let the moderators sort it out. 

regard Joan

]]> Assembly and first prints troubleshooting JoanTabb https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701237 RE: 1→5 tool upgrade: Filament Sensor Fail on one Tool Head https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701169 Sat, 24 Feb 2024 20:32:48 +0000 doing a hard reset and reloading firmware seems to have fixed it.   All tests successful. 

]]> Assembly and first prints troubleshooting Greenhat https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701169 RE: 1→5 tool upgrade: Filament Sensor Fail on one Tool Head https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701126 Sat, 24 Feb 2024 15:57:46 +0000 There is a little access hole right above the nextruder gears.  Try blowing some compressed air in there.  The ball may be stuck.

https://help.prusa3d.com/article/filament-sensor-mk4-mk3-9-xl_465702

]]> Assembly and first prints troubleshooting Brian https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701126 RE: 1→5 tool upgrade: Filament Sensor Fail on one Tool Head https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701078 Sat, 24 Feb 2024 02:58:12 +0000 They work great!   You’re missing out by allowing the noisy few dictate your decisions for you.  

]]> Assembly and first prints troubleshooting Greenhat https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701078 RE: 1→5 tool upgrade: Filament Sensor Fail on one Tool Head https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701077 Sat, 24 Feb 2024 02:56:40 +0000 Nope.  Tool head. 

]]> Assembly and first prints troubleshooting Greenhat https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701077 RE: 1→5 tool upgrade: Filament Sensor Fail on one Tool Head https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701020 Fri, 23 Feb 2024 19:45:13 +0000 Is it the side filament sensor or the sensor in the toolhead? I had the side sensor 2 fail on me after the upgrade. I did hang in until I got someone from Prusa on the line,  he made me do a full reset of the firmware, which fixed the problem.

]]> Assembly and first prints troubleshooting FoxRun3D https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-701020 1→5 tool upgrade: Filament Sensor Fail on one Tool Head https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-700955 Fri, 23 Feb 2024 15:17:13 +0000 After doing the upgrade everything calibrated perfectly except for Tool 2 Filament Sensor.    It fails before asking to insert filament.   I checked that all connections are solid, no wires are pinched, etc.  

I was waiting in line for Prusa support, but I need to go to work...  I'll try again tonight but wanted to check the hive mind for any other ideas. 

]]> Assembly and first prints troubleshooting Greenhat https://forum.prusa3d.com/forum/original-prusa-assembly-and-first-prints-troubleshooting/1%e2%86%925-tool-upgrade-filament-sensor-fail-on-one-tool-head/#post-700955