MakerGear Forum

Hi there,

I (still ) have an old M2, purchased in 2013, and it works pretty well but I'm seeing some issues. I'm hoping to get some input on a possible hypothesis that might explain what I've noticed recently.

I've been getting some uneven prints, and now I see something that looks like unexpected retracts during printing. I physically see the filament being pushed back out if the extruder, typically on direction changes. Here's a YouTube short showing what I see.

https://youtu.be/TwMTppGUgC8

Note that there are no retracts in the gcode as this is happening, neither firmware retract nor gcode rewinding the E value. So I'm guessing there's some physics going on..? But I find that surprising, even if it could be related to being too close to the bed and getting a pressure build up in the nozzle.

I'm using PrusaSlicer 2.9.1, and I based my settings on the MakerGear M2 profile that is included, with only minor modifications.

Very first thing I would do is slice it on something else.. If you have an stl you can share I could slice it on the devil I know (s3d 4.01) and see what it does? Can then email you the gcode. if it is something small I can print it and see what it does on my M2. Or if something small mail me the gcode.. PM me you email if you want to exchange files.

If the machine is that old and has been used heavily, I would suspect an intermittent connection in the wiring harness. On the other hand, I don't know enough about stepper motor drive connections to see how it would reverse direction occasionally...

I agree with GWhite. I found that the flexing of the cables connecting the heat sensor on the bed causes the copper strands to become brittle and ultimately break.

I bought a few marlin boards on the way to discovering what the problem really was.