fsensor fails on a rebuilt MK3 -> MK3S
Just completely rebuilt my MK3 (built in January) to the new MK3S to fix the filament sensor issues, but I'm still not getting successful prints. About every other layer the printer stops and waits for a filament change though the file does not have any filament change gcode.
Since it's happening so often, I watched the terminal in Octoprint and this is the code it came back with:
Recv: ok
Send: N15874 G1 Z1.000*114
Recv: ok
Send: N15875 G1 E0.80000 F2100.00000*30
Recv: ok
Send: N15876 M204 S1250*93
Recv: fsensor_stop_and_save_print
Recv: fsensor_update - M600
Recv: echo:Enqueing to the front: "PRUSA fsensor_recover"
Recv: echo:Enqueing to the front: "M600"
Recv: echo:busy: processing
Recv: echo:busy: processing
Recv: echo:busy: paused for user
Recv: echo:busy: paused for user
I'm running the brand new 3.7 firmware (I confirmed that I am running the new MK3S version) and Sli3r 1.41.3+ through Octoprint. I've tried old files and new files and still get the same results.
I know I can simply disable the filament sensor, but it seems silly to have gone through the entire rebuild just to disable it now. I'm not sure what to check or try next.
Re: fsensor fails on a rebuilt MK3 -> MK3S
Check that you have the filament sensor plug connected to the proper set of pins on the EINSY and that it is the correct way around.
Re: fsensor fails on a rebuilt MK3 -> MK3S
All connections have been verified and it passes the pre-flight check without issue.
The connector on the sensor has the black wire closest to the X axis motor and the connector on the board is in the lower set of pins.
I'm running Prusament Gray, so it shouldn't be affected by the filament.
Re: fsensor fails on a rebuilt MK3 -> MK3S
I didn't find that the pre-check/self-test identified problems with the filament sensor, in that I had it wrong and the test passed. Am I correct in assuming that you still have the MK3 "indirect" sensor and not the newer one that comes with the MK3S? I am not sure what all is in an MK3S upgrade kit, but I know that on my MK3S (purchased that way), the black wire is in the middle of the connector so I am not sure what you have. Here's the diagram from the MK3S assembly instructions:
Re: fsensor fails on a rebuilt MK3 -> MK3S
Update:
So Prusa Chat recommended following this guide:
https://help.prusa3d.com/article/43mduc4zdn-filament-change-prompted-at-the-beginning-of-the-print
After getting everything apart, I found that inserting filament was intermittently triggering the sensor. Everything moves as expected, the sensor starts at zero. When the filament is inserted, the ball moves, the arm moves, and the sensor changes to one as expected. While moving the filament a bit, you can see the sensor flicker between one and zero.
I took the sensor off, pulled the arm, checked the print very carefully, and blew everything out to make sure no dust was in the sensor. I also manually put the flag into the sensor to get it to trigger. It still flickers. Prusa's chat recommended flashing the firmware.
At this point I put everything back together, disabled the new sensor and finished two large prints that I needed for this weekend. I will try printing the arm with the slightly larger flag as well as a few more flags as indicated by Martin L. in the comments on the troubleshooting page above. Hopefully with 4-5 arm options I can get the sensor to work consistently.