Hello, I have a DJI that about 3 years old now. When I insert a fully charged battery, short press then long press the power button to turn on, the drone does nothing. Typically you get this cool sound, then the lights come on. I bout a new battery just to see if that worked and nothing changed. Any ideas what could cause the drone to not go into startup sequence? I checked the voltage on the battery and its well within the DJI specs. Any suggestions or insights would be very helpful. Thanks!