Early Color Television

TV Colorgard

Courtesy of Nick Williams

Made by Gardner Instruments in Bethesda, MD. Its purpose is to accurately measure to intensity of the individual guns in a CRT when placed in setup mode (vertical collapsed into a single line), so the technician can do greyscale tracking without guesswork.

The instructions say it can only be used in non-sulphide tubes having europium red phosphor, and the circuit contains an early form of operational amplifier made by Philbrick which itself is built of discrete transistors and housed in its own stainless plug in case.

The unit in the museum's collection