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UM2 : stepper motors not responding.

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Posted (edited) · UM2 : stepper motors not responding.

Hello everyone! I am the proud owner of a UM2. I have been using this printer for five years now with very little to no problems at all.


Unfortunately, yesterday morning I switched the printer ON as usual and to my surprise I received a warning message showing a "Z switch broken" error. I kind of knew from the beginning that the switch wasn't the issue. However, just to be sure, I checked the switch on both Pronterface and the multimeter. As expected it works perfectly. Now, after reading a few discussion on this forum I realised that it could be a problem with the stepper motors. So I tried the following:


1. Move every motor (including the extruder) on Pronterface, no response.

2. Check bed and nozzle heater, they work perfectly. 

3. Check the voltage across the K1 relay, I get 4.9V between 1-2, 24.5V between 2-NO and 2-C, 0V 2-NC. I hear it clicking. I also added a wire to connect C with NO. Nothing changed. 

4. Checked a few TPs. They all show the correct voltage.

5. Reset to factory settings.

6. Uploaded a new firmware. 

7. Power cycled the power supply.


You guessed it right, none of them worked. What's next to try? Don't tell me to buy a new board 😢


Thank you!



Edited by frederics946
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    Posted · UM2 : stepper motors not responding.

    Hi @frederics946, thank you for your message. Based on your findings I see no particular reason why your motors stopped working. I think it may be a good idea to contact reseller see if they have any ideas for troubleshooting and otherwise consider replacing it with a new board. Sorry, hope it helps. 

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    • 3 weeks later...
    Posted · UM2 : stepper motors not responding.

    Hi @SandervG ! Thanks for the reply, really appreciated! After hours of debugging, it turns out everything was fried: microcontroller and a few drivers. Fortunately, as they say, in all bad stories there is something good. In this case I was lucky to find an incredibly quick and professional board repair service. Aqib was super quick in identifying the problem and he manually replaced all faulty components for a tiny fraction of the board replacement cost.  If anyone in the UK has similar problems, I couldn't recommend his service enough:




    Thanks to him, I'm back printing! 



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