Finding an Epperlein 100 today is hard; finding one that works is even harder. As a result, the first Epperlein 100 watch that I acquired 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 shows this progress:

Epperlein 100 Dorlin Dial and Hands	Epperlein 100 Balance Missing Coil	Hamilton 505 Coils from Factory	Hamilton 505 Coils from Factory	Epperlein 100 Correct Coil Orientation	Epperlein 100 Correct Coil Orientation
Epperlein 100 Correct Coil Orientation	Epperlein 100 Correct Coil Orientation	Epperlein 100 Correct Coil Orientation	Epperlein 100 Battery Side	Epperlein 100 Dial Side with Battery Connection Repair	Epperlein 100 Dial Side with Power to Index Wheel
Epperlein 100 Dial Side	Epperlein 100 Poising the Balance	Epperlein 100 Poising the Balance	Epperlein 100 Poising the Balance	Epperlein 100 Incorrect (Left) and Correct (Right) 505 Coil Orientation