Telefunken FE-VI

The set uses a magnetic deflection/electrostatic focus CRT called a  "Doppelblendenrohr" - double diaphragm tube. The tube is the RFB VI/1 which was manufactured in 1937.

In the above diagram, H = filament, 4 volts. K = cathode, 0 to 250 volts (brightness control). W = control grid (wehnelt). HA = Screen grid (hilfsanode), about 300 volts. Bl.1 = focus diaphragm (blende 1), 600  to 1200 volts (focus control).  A = Anode, E.H.T. 8 KV.

This CRT has an electrostatic lens, consisting of two diaphragms, for focusing the electron beam.

Below is the schematic diagram of the FE-VI-1

(click on pictures for high resolution images)

Courtesy of Eckhard Etzold