After flying my phantom 2 for about a week using factory phantom mode, I decided to switch to naza mode to test out the features. I read the manual before switching, went through the start up procedure and proceeded to take off but failed to lift off the ground. With the stick pushed up all the way, it seemed like it didn't have enough juice to take off. I made sure the battery was fully charged and repeated the process only to get the same results. I even switched back to phantom mode and re calibrated the RC to see if that would fix it and the problem still exists. Is there any thing else i should check using the assistant software or could this be a mechanical problem?