I am plugging a servo control into the F2 port of NAZA. I use it to trigger a camera using the pitch lever at the back of the remote. Everything was working fine up to Wed, including the trigger. On a Fri flight, I noticed the trigger was not working. At first, I thought maybe a loose connection. Back home, I tried plugging two different servos directly into F2, which I had tested before. None of them worked. To make sure it wasn't a transmitter problem, I tried a second DJI transmitter. F2 couldn't be activated. I also plugged the H3-2D, and couldn't tilt the camera. Any idea on why tilt suddenly quit working and what to do about it ?