Phantom 3 Professional No Image Transmission Signal

Hey everyone I have a DJI Phantom 3 Professional drone and for the longest time the app has said “no image transmission signal”. I have tried reinstalling software, and everything you could think of besides taking it apart. I even brought it to a drone shop and they said they didn’t know. Does anyone know of a fix?

If it hasn’t been involved in something bad, the first thing I would do is check all the ‘hardware’. This includes the camera itself, all cable connections (inside and out) etc. Its a process of elimination. Once I have satisfied myself it isn’t a hardware issue only then I would look at the software.