Problem with simple pololu motor controller 18v25


I am doing a project on 2 DOF Motion seat Simulator, and I am Controlling two dc Motors with two Pololu simple Motor Controller 18v25 with the help of Arduino uno. And yesterday while trying to do some test (with just one Motor Controller connected, other one was not being used), after few test I heard a noise and then I could smell like something burnt. I couldn’t see any smoke or something, but then I wasn’t able to stop the Controller on the pololu Software. And then I switched off everything and then found something (attached the Picture First Motor controller ).

And then I thought let me try with the other Controller but this time to be careful I didn’t connect anything I swtiched off the power supply. I didnt connect it to arduino nothing…It was just connected with the usb cable, but now it’s not being detected by the Software and I can see only the green LED on and it is not glowing to its full brightness, it’s very dim. And this Motor Controller is also getting heated up, even though it’s just connected with the usb cable and nothing else.

Can you please help me to know what is the problem, and is it possible to exchange these with the new ones…?

Controller.pdf (173.3 KB)


The exposed trace on the first controller runs to the VIN pin on the logic header and is only designed for small amounts of current for things like monitoring the VIN voltage with a microcontroller. It seems like something in the system caused an excessive amount of current to be drawn over that connection. Also, the trace is largely isolated from the rest of the circuitry on the PCB, so if something like a short circuit on the header side of the connections caused the current draw, it is possible that the board could be usable. Do you have access to a current limited benchtop power supply? If so, can you limit the current to about 100mA and see if the board draws an excessive amount of power (i.e. the full 100mA from the supply) when powered through the terminal blocks? Can you post pictures or a diagram that show how it was connected in your system? What kind of power supply were you using for VIN and what is its voltage range?

What part of the second controller board is getting hot?