artemide tizio desk lamp...can't adjust position?

well, i've seen all the posts for electrical issues, but i've never had one of those. my issue is that the top swing arm won't stay put any longer...in other words the top swing arm is too loose and will not stay in position no matter what counter weight position i try. interesting because i have 2 that were bought the same day and the other one is fine. i've tried to "tighten" the thin connector with the red ends, but all i can seem to do is turn one end and the whole thing turns, but doesn't get any tighter. any suggestions would be greatly appreciated.