My DF has suddenly developed a problem where the fore and aft motors spin far slower than the left and right motors. It doesn't matter if I turn TI on or off. Taking off, the thing just wants to piroette one way. If I hammer on the trottle, I can lift it off and it settles down a bit but it's still pretty much unflyable. Can only get it to yaw one way but not the other. Anyone else experience a similar scenario? Looks like I might have to send the board in for a check up.