Left Motor Runs Nonstop

I’m setting up a Maslow I got from East Bay Source. It came with a v1.5b control board.

I have a good amount of experience with Arduinos so I was very comfortable getting the IDE set up and the board flashed with the latest firmware. After I did that and the arduino rebooted, the left motor started turning nonstop.

Here are some things I’ve tested while troubleshooting:

  • I plugged the right motor into the left port. The right motor started spinning nonstop.
  • I swapped the cables fully L-to-R. Left kept spinning.
  • If I unplug the USB cable from the PC, the motor stops spinning. I think that means that the arduino has lost power and therefore this is a software issue. (that assumes that the arduino doesn’t scavenge power from the barrel plug off the shield to run)

Anyone have any experience with this type of thing?


To me it sounds like the issue is with wiring at the controller. It could be:

  • a wire trace on the shield (upper board) not connecting
  • a bent left channel encoder pin that isn’t contacting

By switching cables, it isn’t the cable.
By switching motors, it isn’t the motor or the motor’s encoder.

I have seen the motors spin like that when the plug was not fully inserted and I’ve seen it happen when the shield and the arduino controller come unplugged slightly. shield may not be pressed in all the way.

Can you squeeze the top board and the bottom boards together tighly so they have full contact? You can zip-tie the boards together. Sometimes when mounting the lower board and then with the cables going in the upper board, the upper board pulls loose. This tends to happen more (in my experience) on the M2 shield because the plugs are side-mounted. If things shift, the cables push the shield off rather than pop out. I use 2 of the small zip ties and run them around the board and heat sink to help hold things together.

@EastBaySource: any thoughts?

Thanks for the reply!

I did find a remedy to my issue early this morning. I found firmware on the Eastbay site that had a “b” at the end of the version number (I presume a custom version is required for their shield?). Using those files, I flashed my Arduino and the problem was fixed. I’ve gone through all of the rest of calibration successfully since.

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great to hear!