If it's a pulley cage tension problem, it should be an easy fix. Just remove the stopper bar (I think theres a slot on the tip to use a screw driver on) on the knurled barrel next to the pulley cage that keeps the cage from spinning back and wind in some tension by spinning the pulley cage assembly counter clockwise. reinstall the stop when there is enough tension again. Unless the lower pivot tension spring is broken, this should fix your tension problems.

Chombi