Newbie Needs Help

I'm having issues with new spring installs. I have the right-sized springs but I am having issues. I Remover the old spring tension the pulley and cables while the torsion bar is locked, then tensioned the spring, and release bar, and the door goes up fine but on way down the cable comes off the pulley and wrap around the torsion bar locking the door halfway down locked by the stuck cables. This Happened several times, any advice would be appreciated