Internal Boom winch

[jayw]

I have a roller furling boom on my 1972 35-foot Bristol sloop. Inside the fitting on the mast end is a small winch that pulls a cable attached to a small car on the outside of the boom that pulls the clew of the main sail out towards the end of the boom.
The winch does not move in either direction. I've taken the fitting off of the mast end of the boom, but can't really see what the problem is. Seems that there is not enough corrosion to prevent movement, I'm wondering if there is some sort of release mechanism that is not visible or missing. Does anyone have any experience with this kind of rig?
Thanks in advance for any ideas.
Jay

[Idiens]

Some photos would help....

[knothead]

I recently had the opportunity to service one of these. It was frozen solid and I discovered even though the corrosion didn't look that bad, it was in fact corrosion that was the problem. It doesn't take much to freeze a shaft where there is a combination of stainless and aluminum. Your only option it to completely disassemble the entire thing and remove any oxidation until the shaft spins free. Reassemble using never-seize.

[jayw]

Thanks for the advice, guess I was hoping to avoid more disassembly.