Tail not responding

[sparts]

Hi,
All of a sudden my tail has stopped responding and the heli spins on its axis.On stopping and re spooling up the tail works but then stops again.I've checked the manual and all seems as it should.
But I have noticed on using my DX7SE it sometimes doesn't always seemed to be bound.
Any idea's ?
Thanks

[sparts]

Sorted it..It was the tail pitch slider pin.It had popped out of its housing..