Weak Throttle Up

[Pcushing]

My Phantom 1 all of a sudden can't take off. When I throttle up, then motors rev up but no where near with sufficient power. I've tried updating, recalibrating, etc. Suggestions?

 

[Pcushing]

Problem solved. After much tinkering, I realized than when I reset the transmitter, it switched from Mode 1 to Mode 2. As a result muscle memory was controlling the sticks the wrong way. Switch backed to Mode 1 and there was much rejoicing.