If your Myo armband is not showing any activity on the LEDs when plugged in, there are a few things you can try:
1. Check the cable. Make sure all connections are secure and that there is no damage.
Try using a different USB cable to make sure it's not damaged or losing data.
2. Try connecting Myo to a different USB port. In rare circumstances, some USB ports will not be compatible with Myo.
Try all the USB ports on your computer in order to narrow down the possible culprits. If you're using a powered external USB hub, use one on your computer instead.
3. Instead of connecting Myo to a computer, try to connect it directly to a USB wall charger (if you have one).
If Myo begins charging, the USB connection to your computer is not delivering power to the armband.
4. Connect Myo to another computer. This will rule out any computer-specific issues.
If you've tried all three troubleshooting steps and Myo is still not charging, please send us a note at firstname.lastname@example.org.