I know what you are up against; I have been dreading the day when one of mine goes down, because it would mean the death of the lathe. Have you tried contacting the people that made the resolver for Cincinnati?
MOOG Components Group
1213 North Main Street
540 552 3011
The division has been bought-out and resold several times so it is hard to find somebody that knows very much. I dealt with a Missy Meredith at 1-800-336-2112 Ext 181 I sent mine in for a free inspection with the hopes of getting it repaired, but it was "beyond economical repair" at that time. Things might have changed I would contact them and see what they can do for you.
I also had some sub-spindle resolvers die and they didn't have any, but they tracked two down and bought them back from an old customer then inspected them before selling them to me. It turned out to be a great deal and kept 2 of our 250MS lathes still making parts.