Extruder motor ticking back and forth without advancing
It's my first post for help, please be kind. 🙂
My extruder's not working, and I think the motor might be bad - but apparently that's not a common issue.
I have a MK3s+ with an MMU3. I changed the hotend somewhat recently, and only got a few good prints afterward. It hasn't been extruding, and there are unpleasant grinding and clicking noises.
I opened it up to check the bondtech gear, and see that it's just moving back and forth when I use Settings -> Move axis -> Extruder.
If I apply a little downward pressure to the gear teeth as it's doing this, it will move (which is how I got it aligned so I could see the flat side and the screw).
I'm able to manually push my PETG through the nozzle at 230deg.
What do you think? Do I need to replace the motor, or are there other mechanical obstructions I can check for first?
Best Answer by Artur5:
Usually when a stepper turns back and forth a few degrees continuously it’s because one of the coils isn’t working (burned/broken coil or a damaged wire on the cable). With a bit of luck, could be a loose/intermittent electrical contact of the cable plug on the socket. Frankly, this is a remote chance, but try to wiggle the plug in the socket, just in case..
You could also swap inside the Einsy board the cables of the extruder and the X or Y steppers. With the cables swapped, if the X/Y stepper turns without problems when you select ‘move extruder motor’, the extruder motor ( or the cable) is faulty. If the extruder motor works OK when you select in the menu ‘move X/Y axis’, then the problem it’s in the Einsy board (a damaged mosfet, probably ).
RE: Add an inline gif
Here's a gif, in case the .mov is weird or sketchy.
RE: Extruder motor ticking back and forth without advancing
Usually when a stepper turns back and forth a few degrees continuously it’s because one of the coils isn’t working (burned/broken coil or a damaged wire on the cable). With a bit of luck, could be a loose/intermittent electrical contact of the cable plug on the socket. Frankly, this is a remote chance, but try to wiggle the plug in the socket, just in case..
You could also swap inside the Einsy board the cables of the extruder and the X or Y steppers. With the cables swapped, if the X/Y stepper turns without problems when you select ‘move extruder motor’, the extruder motor ( or the cable) is faulty. If the extruder motor works OK when you select in the menu ‘move X/Y axis’, then the problem it’s in the Einsy board (a damaged mosfet, probably ).
but apparently that's not a common issue.
It isn't common but when a stepper fails this is a recognised mode. First check the connections by pulling and replugging the connection at the Einsy end.
If that doesn't help remove the motor and turn the shaft by hand, I suspect you will feel both the expected even steps and an uneven grating which would indicate a failed internal bearing - these cannot easily be repaired so a replacement motor is in order.
A last crosscheck is to swap the motor connector into the X axis socket and move the X axis via the lcd menu; if the motor continues to judder that confirms the failure, if not there *might* be an electronic issue.
Cheerio,
RE: Extruder motor ticking back and forth without advancing
Thanks, @artur5 and @diem. In the process of following both of your suggestions, I found the extruder's connection was just loose on the Einsy end! What a relief.