[Jeffhs]

jstout66,

The "electric tuning eye" was just that. It was a feature of Philco's high-end consoles of 1967-68 vintage that assisted in the proper tuning of the color picture. The fine tuning control was adjusted until the two horizontal segments of the tuning-eye tube (located, as you said, directly above the channel selector) just met without overlapping; this was the correct setting for best sound and picture. It took some of the guesswork out of tuning these sets, but there was still the matter of oscillator drift over time which would require the viewer to reset the fine tuning. (Some of GE's better TVs of that period had a variation of the tuning-eye system; the GE sets, however, used a tuning meter, rather than an eye tube, to indicate proper fine-tuning adjustment. When the tuning meter was at its highest reading, the viewer could be reasonably sure his/her set was tuned for the absolute best picture, sound and color.)

AFC circuits and, later on, quartz-synthesized tuners eventually eliminated the fine-tuning knob altogether, but Philco's tuning-eye system, not to mention GE's tuning-meter arrangement, were a step in the right direction. Color TV is very unforgiving of tuning errors; if the fine-tuning adjustment is not set exactly on the center of the channel, you can lose the color, sound or both. There were stories in color TV's early days of set owners who would watch an entire program in black and white (monochrome), unaware of the fact that one simple fine tuning adjustment would change the picture to color--glorious, living color! A TV station in Cincinnati (WLWT, channel 5, NBC), in its early years of color telecasting, would often get calls from its viewers if even a station break was not seen in color (the station claimed to telecast 100 percent of its programming, including station breaks, commercials, etc. in color, in keeping with NBC's own claims of being "the full color network" starting in 1965). These viewers would call the station to find out if a given program was being broadcast in color, thinking that their own TV set was at fault if they were seeing the same program in B&W.