Things to check....
1) Are you using the correct method to power on (I'm sure you probably are)
2) Have you checked the calibration in the NAZA assistant. If this is a first time for the 14sg make sure the throttle channel doesn't need reversing
3) Are you close to an international airport and hence in the DJI no fly zone. If you are it won't power on.
Thats a starter.... I'd hook it to the assistant first to make sure it all checks out there.
If you are still having problems the best bet is to take a video of your start up procedure and lights and post in here. Also some detail on the 14sg setup, how long you've had it, has it worked on the Phantom before etc.
