Spektrums don't work too well on some electrics. I can't get my spektrum to work with my Mamba. I think it has to do with the way the ESC does the initial turn on.

I know on the mamba when you power it up the controller gives power to everything but don't work until it sees 4 seconds of neutral input. In those 4 seconds the Spektrum is trying to setup and looks to make sure its connected to the steering and throttle channels but because the ESC is waiting for the 4 seconds of neutral nothing happens.