Blinds, Shades and Shutters - rolling shutter broken

i have exterior aluminum rolling shutters over my rear windows. they coil up into an overhang constructed above the window. pull cords strung through the window frame into the house are used to open/close, with a spring loaded reel on the inside to take up/release the slack.

one of them recently broke - the cord is still intact, but the outside reel (for lack of a better term) appears to be free-spinning, no longer connected to the shutter. I can't see it since it's inside the custom-made enclosure, but I can feel/hear it.

anyone know how these things work? would like to know what I'm in for before I tear open the enclosure in the middle of the winter. or should I just leave it until spring and hire someone.

Do a Google search for roll-up shutters and you'll find a lot of information. If you know the name of the manufacturer, it will make it easy to locate parts or have it repaired.