Just as a thought, I have a DX6, not 6i which I bought last year from Alshobbies, very cheap because it was Mode1 and couldn't be changed. It came in a Graupner box as it was sold by them here.
Right from the beginning I had trouble with the servo throw on the Aeleron channel. Only about 20° right and left. Had to alter the linkages to get a half decent rudder movement. Trims did not work on the throttle at all. Put up with it because it was cheap! Then one day I switched on and the rudder servo drove to one end and stayed there, only direction one way. Got in touch with Graupner (Still under Guarantee) and sent it back. They returned it after 5 weeks and said it was OK. It wasn't ! Then sent it to Horizon Germany, who said that it was a software problem and the Outfit should be replaced, but as it was bought in UK, had to be done there.!! sent back to Alshobbies at Hainault, where a very helpful Mr Stuart Warne sent it to Horizon UK, who re programmed it and sent it to me. It works now, with full servo throw everywhere, but I do not trust it and certainly would not put it in a plane! Time will tell if it is OK completely.