-רחל

I don't have a NQX but I would try to move the motor cables to the opposite plug and see whether the failure moves along. If the front motors run properly from the back plugs the board is faulty (the FETs?). If not, the motors are bad.

BTW...
It is a hoax that gyro stabilized items require level.

At different temperatures and while any movements the gyro system emitts different voltages which are detected and analyzed by the stabilizing system.

If there weren't different voltages at different temperatures the initial phase wouldn't be necessary at all.

While the initializing process the system checks the actual voltages and does a zeroing.
The new zero is the point where the system assumes it doesn't have to counteract any moving.

"In flight" the system always tries to maintain zero voltages. Zero voltages happen on "no movement" and "no movement" happens when the copter is level. So it levels the copter by itself all the time. The angle while initializing does never come into play.