The first link below will take you to a web site which has information on repairing a Eureka clock. The second link is for a magazine article on how to build a Eureka clock. Between the two you should get a pretty good idea of how your Eureka clockworks and how to repair it. There's also a book “The Eureka clock” by Dr. F. G. Shenton. If you can find the book it has all sorts of the useful information on the Eureka clock.