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prusa3d / Original-Prusa-MINI

Original Prusa MINI 3D printer hardware
https://www.prusa3d.com/original-prusa-mini/
GNU General Public License v3.0
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Mesh Levelling has very weird behaviour #5

Closed AndyThirtover closed 4 years ago

AndyThirtover commented 4 years ago

4.0.1 Please view:

https://www.youtube.com/watch?v=rOWLI0K9chY

You'll see that the points 1-2 work perfectly and the 3-4-5 only go UP. 6-7-8 are ok and and that the MINDA does not operate. Notice that 6-7-8 are ok and then 11-12 and 13 also go up (as do all of the points on the left hand side of the bed.

The net result is that this printer cannot be first layer calibrated. It seems that the issue gets worse every time I power cycle/factory reset the printer. I've managed one print on 4.0.0 but since the 4.0.1 upgrade this sad Prusa Mini has not managed a single print ;)

lennertvdkort commented 4 years ago

On one of the FB-groups there was someone that had the same problem. One of the wires of his Minda is broken. When extruder goes to the end the strain on the wires is to big and then the broken wire doesn't make contact anymore. This is IMHO a big design flaw, the wire bundle almost makes a 90° bent when the extruder is at the end. Mine also is that bad(my mini has a skewed bed and my smooth plate is already worn because of that on one side.. Not a good start)

AndyThirtover commented 4 years ago

@lennertvdkort I agree. I have taken the cable tie out and I can see that the MINDA LED flashes as I wiggle the cable. Will request a new one after the Christmas break -- which starts now!

DooMon commented 4 years ago

Same problem here! 1-3, 5-7, 11 are ok, the rest MINDA goes only up.

michalxfanta commented 4 years ago

This is not a firmware issue, it is probably caused by broken MINDA cables.

gregsaun commented 4 years ago

@michalxfanta I suspect this is due to the too short cables on the hotend which wear the cables quicker than expected. I have made an improvement on your parts to help, you can find it here: https://www.thingiverse.com/thing:4065410

Is Prusa working on a solution for this issue? The best way I see today would be to provide a longer heater cartridge cable because this is the shortest and most problematic one.

JohnnyDeer commented 4 years ago

Hi, this behavior is because cables of MINDA are broken. We sended replacements with new MINDA type and improved cable holder, wich solving this problems. If you still have this kind of MINDA issue please contact our Tech Support. Thank you.