Between 1952 and 1956, Helmut Epperlein's company develop a prototype electric watch. The company then enters into a partnership with the Hamilton Watch Company and further work on a prototype progesses using contacts and magnets supplied by Hamilton; the end result, in 1958, resembles a Hamilton 500.

The 500-type Epperlein 100 prototypes had various technical problems and in 1959 Epperlein change the design and release a watch of the same name which now resembles the Hamilton 505. About 5000 were produced but about 30% of these were returned to the factory with problems and destroyed. In 1960, the company announces the development of a ladies electric watch but it never reaches production and the company files for bankruptcy in 1971.

Finding an Epperlein 100 today is hard; finding one that works is even harder. As a result, my Epperlein 100 is a work in progress: the dial is marked "Dorlin" and the movement marked "Paul Portinoux". When it arrived, it was missing the coil on the balance wheel and I'm currently in the process of experimenting with a Hamilton 505 coil on the Epperlein balance. The watch is now running but currently gains several hours a day; further work needs to be done on the poising etc. The following series of photographs show this progress: