mine wouldnt turn either, its stuck, good luck with it, i snaped my head off the screw, had to heat it up and take it out with a pair of plyers so be verry careful, spray some lube on it and dont force, lots of small "bumps" will work best, and as for a turn signle sounds like the spring for return is broke or fell off, not sure how that even works, but itshappend in a torus my g ma owned and thats the only reasone i think of that