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UMO+ not moving extrusion motor, also problem with burnt plastic "boogers"

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I recently got and assembled the UMO+ and was able to get a few good prints out of it after some trial and error. However, I was also getting some burnt "boogers" of plastic all over my prints (I say burnt because the grey plastic was turning a brown color). At the time, I didn't mind too much because any that were left over were easy to break off the prints and they still looked good. However, a few days ago I did a print over night, and I think the print head got very clogged, I'm assuming because of running into all of those boogers as it was still printing, the result of which caused the plastic to stop moving through the print head, and the extruder to grind up the plastic filament because it wasn't able to push it through the bowden tube anymore. I've been in the process of cleaning out the print head, aluminum block, etc. (everything around the nozzle got nicely coated in melted plastic). If you have any suggestions for that, I'd be glad to hear them.

However, the biggest problem I've found is that since then, I'm not able to control the extruder motor anymore. It was working for a little while after the initial failed print, but now it just won't move the motor at all. Just as a quick troubleshoot, I tried plugging in the extruder motor to the y-motor plug on the motherboard and the extruder motor moved when I moved the "y-axis" in the Move Axis menu! However, the really bad news is that if I tried plugging in a different motor to the extruder plug (in this case, the y-motor) it wouldn't move that-motor either when I tried to move the extruder in the Move Axis menu... Does that mean that there's some problem with the electronics themselves? I've tried reflashing the firmware and that doesn't seem to have fixed it at all. If you've got any other suggestions to troubleshoot or to propose a fix, I'm more than happy to hear! Thanks.

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Just a quick thought, have you tried swapping over the driver chip for a known working one (i.e the Y axis one) in your case it could well be that the chip overheated and its fried itself as alot of your symptoms are what lead me down the bath of lowering the power to my extruder in the first place, failing prints and blocked heads were common place before i did.

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Also to do a full clean of the nozzle/block/etc. Boil them with a bit of salt and vinegar for as long as you need. Or use a airdryer to keep all hot while you clean them.

To avoid filament leaks assemble as follow:

Do everything as the manual but let the nozzle just a little tinny not totally (in) (just a tinny little gap). Then put the heat barrel insulator (the one with the peek). When all its tight (don't over do it just well fit) set the nozzle assembled and preheat to 200C. Then with the propper tools hold the aluminium block and tight the nozzle for good.

The problem with how the manual assembly it's done it's that without a propper fit on 'heat' the thermal expansion of the metal will most likely leave a gap for the filament to leak.


Edited by Guest

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Thanks for your help, guys. Turns out I'm stupid and forgot that there's a safety feature that the extruder motor won't move unless you're heating the hot end (which makes sense), so I didn't actually have a problem with the extruder motor channel.

I ended up cleaning my block/nozzle/heat pipe up using a soldering iron to heat them up and a wet paper towel and Q-tips to wipe away the plastic. It wasn't great, but I got most of it off. I also really appreciate the tip about tightening up everything in the hot end while it's hot, that definitely solved the leaky plastic issue, which (I think) was the original cause of the problem in the first place.

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