I picked up a Phantom today at "Bargain Hunt" which is an overstock type store. It was a good deal but I was worried it wouldn't work correctly. I've had an AR Drone 2.0 for several months that I crashed badly and have been unable to get flying again, so I figured this would be a good upgrade. The back left motor seems to be locked up. No big deal, I can replace that no problem. The only thing I'm worried about is that the LED on the bottom of that arm is not lighting up either. Since I'm new to the Phantom, what should be the first thing I check as far as diagnosing why that's not working? Other than that the copter starts up and the other three motors go full throttle with no problem, so I'm hoping this is a relatively easy fix.