Fuji GL690 stuck darkslide/curtain

So, I made the mistake of try to shut the darkslide/cloth curtain on a GL690. It's now stuck shut, and doesn't want to return at all. Apparently this mechanism is fairly problematic, too. How exactly does it work? Does it simply have a set of ribbons that pull it from one drum to another, in the same fashion as a typical cloth focal plane shutter? Any pointers on what has to come apart, to wind it back up?

Unusual. Typically GL and GM dark curtains are much more reliable than G series dark curtains. Especially since they have stronger springs. I've only seen the G series curtains and they were very much like a regular focal plane shutter with the ribbons and such.

Well, I played around with the winding key for a while, and it popped back open and now operates flawlessly. Glad I didn't have to tear this thing apart...