What Pololu? Driver Boards are fitted to the Rumba ?

Discussion in 'Calibration, Help, and Troubleshooting' started by Old_Tafr, May 28, 2016.

  1. Old_Tafr

    Old_Tafr Well-Known Member

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    Just thought I would buy a couple of stepper motor driver boards as spares.

    Had a look at the five boards on the Rumba but can't see any part number, name or description and don't necessarily want to pull the boards out to find there isn't this info on the underside.

    I have also seen some info saying that some existing Pololu boards have been discontinued and replaced by newer models with more capability.

    What do I order as spares?
     
  2. Alex9779

    Alex9779 Moderator
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    The stock drivers are DRV8825 A4988. Brand unknown GE Tech...
    If you order some spares collect information on them before you order especially the docs for adjusting them is needed. Not every layout of them uses the same resistors so the V-ref voltage you measure to adjust the motor current can be different from what you have to set the E3D drivers to.

    You can go for some other drivers, some discussed is this thread https://forum.e3d-online.com/index.php?threads/quieter-and-better-stepper-drivers.1403/ but then you gotta find out everything yourself how to adjust the jumpers in the Rumba board because there is only some general info not specific for the Rumba available...
     
    #2 Alex9779, May 28, 2016
    Last edited: May 28, 2016
  3. Old_Tafr

    Old_Tafr Well-Known Member

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    Interesting... Thanks ! some more reading to do.
     
  4. mike01hu

    mike01hu Well-Known Member

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    I have one faulty driver that was replaced temporarily with a bog standard A4988 Chinese look-alike that was kicking around in my box of bits and that was OK with the same voltage setting spec, then E3D sent me a replacement which has the 4988 chip and that was supplied by GE Tech.
     
  5. Mike Kelly

    Mike Kelly Volunteer

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    I'm pretty sure they're A4988 drivers, but I'm trying to verify
     
  6. Alex9779

    Alex9779 Moderator
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    Oops maybe I was wrong...
     
  7. Old_Tafr

    Old_Tafr Well-Known Member

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    4988 on the chip

    For this apparently the sense resistor (assuming a real Pololu 4988) is 0.1 ohm
     
  8. mike01hu

    mike01hu Well-Known Member

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    . . . and on the underside you might see GE Tech.
     
  9. Alex9779

    Alex9779 Moderator
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    Ya saw it myself now... Pretty small text on the chips... The purple colour irritated me... Corrected my post...
     
  10. Old_Tafr

    Old_Tafr Well-Known Member

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    Getting closer to what I need to order........... unless of course the fakes have GE Tech on them too :mad:

    The next question is a reliable supplier?
     
  11. mike01hu

    mike01hu Well-Known Member

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    GE Tech??? :rolleyes:
     
  12. mike01hu

    mike01hu Well-Known Member

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    They seem to be listed as "Getech" but no specific company details. I suspect they are another Chinese supplier.
     

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