The OSBo and expansion board have all been tested before we ship them out. It’s not so easy to test them without a tester. Basically you will need a microcontroller, such as an Arduino, to send control signals to the board to test various components on board.
When using expansion board, one thing you should be careful about is inserting the extension cable correctly. Now that the extension cable uses polarized connectors, it’s unlikely you will insert them in the wrong way. Still, if you are inserting the connector with the case top removed, it’s possible to misalign the connector with the pin headers. When this happens, you may end up connecting a GPIO pin to ground, and that can potentially damage the BeagleBone.
If you want, you can send back your boards to us so we can use our testers to check if the boards are still working. Email to [email protected]. Thanks.