[old_tv_nut]

Wow - they even had a color defeat switch. This would make the indicators useful as the user might have turned the color off with the defeat switch.

The reason for a color defeat switch was for cases where a set was used in a fringe area and the noise might have made the color killer unreliable. The color killer control could be set to make sure color programs got through, but the switch could be used to eliminate color snow on black and white programs without disturbing the color control setting. Obviously the color killer and color indicator could have different thresholds. I wonder if the color indicator tended towards false positives or false negatives under noisy conditions.