steering on emaxx not working

[suicideneil]

Sounds like a rather nasty short. I would suggest trying a different servo on the 'damaged' rx, and the spare one too. That should tell you if its just the servo or the rx too thats buggered. If nothing happens when the bec connected up, sounds like that is fried unfortunately. Did you have the system powered up when you were soldering/re-wiring?