motor spinning without stopping after a battery is plugged in

[chingchi]

Hi,

I have followed the tutorial to assemble two crazyflies.
One of them is abnormal when it connects to a battery.
Its motors start spinning extremely once a battery is plugged in.
To ensure that the battery is fine, I have exchanged the battery of another crazyflie, but it doesn't help.
So, I flashed the latest firmware (crazyflie-2017.04.zip) to it.
After flashing, the self-test is still passed, but it still doesn't play the start-up sound melody.
Please refer to the video as below:
https://youtu.be/VVUHE3ZNHf4

Thanks for your help!!
Ching Chi

[tobias]

Looks like a production error. The positive and negative on the battery cable has been soldered wrong. As a first step you can swap the pins in the connector and test but of that doesn't work send us an email at support@bitcraze.io.

[chingchi]

Hi,

You are right!! The positive and negative wire are soldered incorrectly.
After swapping them as the attached photo, the problem is solved.
Thanks for your help:)

Ching Chi

[tobias]

Sorry about the inconvenience and great that you sorted it out. Just let us know if you have any further problems.