Lemontron Troubleshooting

Belt is rubbing on left top plate

Your left top plate is bowed due to extruder/bed wires trapped underneath.

Belt is rubbing on right top plate

1. The wires in the PSU cavity are too springy or your have a clearance issue and are pushing the top plate up. Redo the wiring so that it’s cleaner.
2. Some non-MeanWell, alternate PSU’s such as from AME, have a taller capacitor. Carve out your top plate.

The tool head clip broke and the belt popped out

1. Reprint it in plain old PETG or PLA (but not silk PLA, matte PLA is not ideal either). Both plastics have excellent layer adhesion.
2. This time, push the belt all the way in so that it bottoms out. If the belt isn’t pushed all the way in, the clip has no strength and will fail.

Carriage screws are bottoming out

Your X rail is thinner than the standard 6.5mm. Drop some spacers (the ones for the Z rail) into the two holes and tighten.

Ceramic heater broken

The Positron 90 hotend uses a Bambulabs heater. You can replace the heater with a Bambu X1C ceramic heater.

End stop still triggered after retract

1. Make sure you have a BLTouch jumper on your MCU. This connects an internal pull-up resistor which is critical to sensing the probe signals.
2. You were just testing it with your finger, you pushed it all the way in. Under normal probing, the build plate gently taps the probe.
3. Check the back of the probe for damage.

M3 Screws are not passing through the holes properly

This problem is caused by overextrusion on the printed parts. Holes will be sized too small and this makes assembly harder. Unfortunately, you’ll need to tune up the printer you’re printing with. Calibrate the flow rate and reprint the affected parts.

Friction in motion system

1. Check your idler bearings. You can mark them with a sharpie for visibility and give them a spin.
2. Check the motors themselves. If a small gap is not applied when tightening the grub screws, the gears can bind against the motors.
3. The belt could be out-of-spec, try using my 6mm belt splitter on Printables.
4. Check all the shims that are supposed to be there are present.
5. Check that all the idlers are tight; loose idlers can bend and rub the surface they sit on.
6. Lemontron Rev E; After some time, the plastic in the carriage block can drift, needing retightening, but if you retighten enough, it’s just “dishing” the medium shim which will ultimately bind the idler. For mine I used ABS, and this fixed the issue compared to my previous PETG one.

Leaking hot end

If you see plastic blobs exiting the hotend in places they shouldn’t, see how to rebuild the positron hotend.

Prints are coming out mirrored

You swapped your A and B motor wires.

Stripped motor threads

Remove the factory-installed bottom screw in the stripped hole. Use the longer version of the top screw (button head or countersunk) in the top of the motor instead. The motor doesn’t need all of its screws to work.

Tool head colliding with bearings / rear chassis

Your tool head is tilted: The cavity which surrounds the carriage block must have been printed too small to mate properly.

X rail is chewing up the belt

Your X rail cuts were cut too close to the holes. But don’t worry, there are printable pulleys to hold the belt clear of the rail.