Zumo motor problem - Pololu HP 50:1

so I finished assembling my Zumo and everythinh was OK until my fifth test ride with Zumo. After uploding sketch from Arduino IDE to Arduino Leonard and turning Zumo On and putting this wonderfull toy on the ground it tourned up that only one motor (on the right side) is working. I check my code and everything looks OK (it was based on motor code from zumo examples) , after this I uploaded the motor program from zumo github library turn Zumo On and situation was exacly the same only right motor was working. After this I pulled out left motor from Zumo Chasis and connect it to Arduino and everything was OK, after this I mount motor back and situation is exacly the same - only one motor is alive :slight_smile:. After assembling Zumo I’ve checked every part (Buzzer, motors etc.) and everyting was OK.
I’m using this two motors Pololu HP 50:1 and Arduino Leonardo.

Any advice? What should I check?

I’m totaly new to robotics and Arduino (ok with this one I build some project but with sensors).
… and english isn’t my native language so you have to excuse me all my mistakes. :smiley:


I am sorry you are having trouble with a motor on your Zumo. I am not entirely sure what you mean when you say you “pulled out left motor from Zumo Chasis and connect it to Arduino and everything was OK”. Can you describe in more detail how you removed the gearmotor from the Zumo? How exactly did you test your gearmotor with your Arduino?

If you have a multimeter, can you try checking continuity between the motors and the driver outputs (they are the middle 4 pins on the front of the motor driver chip)? You could also measure the voltage while the motors should be running. However, if you do this, please be very careful. If you try to probe the driver IC while the board is powered, it is easy to short adjacent pins.