The first-gen Cyclone has the general style of cage spring seen in Shimano derailleurs, a spiral spring with tails sticking out both ends. The implementation's weird, though... the inboard tail is the one that gets anchored stationary to the front "knuckle" of the derailleur. The outboard tail plugs into the pivot bolt, which then threads into the pulley cage plate until it bottoms. So the spring turns the pivot, and the pivot turns the cage.

Among other things, it appears to me that if the pivot simply came "unlocked" from the pulley cage, it would mimic a broken spring, so jimmuller, you might start by just grabbing the pulley cage with one hand and checking whether the pivot bolt is no longer locked against it. If the pivot's not tight, try snugging it down (hold the pivot stationary so you don't tweak the spring, and rotate the cage to tighten it) and see if you now have spring action again. If that's what's going on, some strong threadlocker seems advisable.