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J0 only spins in one direction

When homing J0, it spins for 2+ revolutions. And when trying to jog it in the + or - direction, it only spins clockwise. I assume this is a software or firmware problem. Will there be an update?

Software version

Firmware version 1.21


Based on your description it seems motor m1 is not spinning CCW direction and it is most likely due to either a bad connector to the driver of motor m1 or miswiring of the cables that are connected to the driver of motor m1. Did you get the unassembled robot or assembled?

I received a disassembled robot. I've isolated the problem to be something with driver D1. Steps to reaching this conclusion below:

  1. Use port m1 from controller to drive motor M3 using driver D3. (success. no firmware problem with port m1)
  2. Drive motor M1 from driver D3. (success. M1 motor wired correctly)
  3. Drive motor M3 from driver D1. (failed. only moves clockwise)

This narrows the problem down to something with driver D1.

Please advise.



It is very unlikely that there is a problem with the driver. Most likely it is the connector that bring Pulse and Direction signals to the driver or the connector on the board (M1 connector) might have loose connection.

The m1 connector drives motor M3 using driver D3 just fine (so no loose connection), and neither pulse/direction connector for D1 or D3 work on D1, but both connectors work on D3.

Is it safe to say something is wrong with driver D1? Or is there something else I should try?

Please advise.

It is very rare to see a failed driver as opposed to a loose connector.

Could you please confirm this experiment: if you replace D1 with D3, the issue is fixed? In other words, if you connect all connectors of D1 to D3 (A+A-B+B-, VCC, GND, DIR, PULSE) then motor 1 rotates in both directions as expected.

I've confirmed again that using all the connectors from D1 with D3 fixes the issue. (Result of #2 in my first reply.) Also, driving other motors using D1 has the same issue of rotating in one direction.

I understand it's rare to have a failed driver. Any recommendation on how to repair it other than receiving a replacement?

Please advise.


It seems the problem is a failed driver. Before installing the new driver, please confirm the DC voltage input to the driver, is about 35V.

Please send us an email with your shipping address to "" and we will send you a new driver. Hope it fixes the issue for you.

Replacement driver works! Input voltage was 35.23V. J0 is now able to rotate in both directions. Thank you.