I had the exact same thing here after my rotor blades hit a cardboard box (I broke a servo).

I could fly and it acted just like the sticky pitch problem, I tore the head apart, cleaned and lubed and reassembled it, the problem was still there, then I started to look at the servos.


Try this' with the heli OFF and the battery unhooked :

Level your swash plate

Grab your blade mounts and twist them (twisting the blades, PITCH) and watch the servos.

All of the servos should move together (try it a few times). if one does not then move that servo by hand and compare it to the others.
If it is stiff you proabably have a bad servo.

If you find a bad servo swap it out and it should work right again.


Also look at www.bladecprepair.com there is a lot of good info there.