[old_tv_nut]

3 PMTs. Can't recall if the phosphor appeared white or greenish to the eye. I know some RCA catalogs listed a color FS CRT that appeared greenish to the eye.

Edit - found the 1958 catalog - lists 5AUP24 "Intended primarily for use as a scanner in a color video-signal generator. Feature useable radiant energy output over the visible spectrum, extremely short persistence..."

"Phosphor P24 is a short-persistence phosphor with green fluorescence and phosphorescence. Its spectral-energy emission characteristic has sufficient range to provide useable energy over the visible spectrum requried for generating color signals from color transparencies."