Send your tx back to horizon and have the RF board checked, I had the same issue and lost a plane and then pulled my hair out trying to figure out why,long story short I upgraded to a DX7 and not a problem since.The DX6i burned the RF board about six months into use with no warning and no problems any other time.Horizon fixed the issue with really fast turn around but i was on my own with the destroyed plane and gear Good Luck