RE: dx6i
You've checked your battery and connections? You've verified that you're getting proper voltage to the receiver? If that's the case then binding is the only other issue I can think of. You didn't say you've tried rebinding, so if you haven't, go ahead and try it. If that doesn't work, maybe you can get with someone who flies Spektrum/JR gear and see if your receiver will bind to another transmitter.