The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com   Campbell D Portable High Frequency X-Ray Coil I repaired this coil over a period of years.  I made by hand the Mica Capacitor, the Pancake Coil, Ebonite Discharge Posts, Brass Dischargers, Moulded Knobs (made from the originals on my "E"), and unusual Power Cord!