[Jeffhs]

One thing many early color TV owners did not realize was that the fine tuning control had to be set exactly, to get any color at all. I'm sure many repair shops' techs in the '50s-'60s made house calls on color sets which the owner stated had "no color" in the picture, only to find that the fine tuning was just a hair off. A slight tweak of the control was often all it took to convert a black-and-white picture (from a program known to be telecast in color) to full color. (Some people also had the sadly mistaken idea that programs telecast in monochrome could somehow be converted to full color if such programs were viewed on a color set, and they may have thought their sets were malfunctioning if normally b&w shows could not be made to appear in color.) The "no color" problem could also be caused by a curious set owner who somehow discovered the color killer adjustment on the rear apron of the set; the person could have turned this control so as to force the killer to operate full time, which of course would result in a loss of color on color telecasts. The technician often warned the customer against adjusting those rear-panel controls, often telling him or her that misadjustment of certain controls could damage the set; some techs (with the customer's permission) taped off the service adjustments to prevent repeat nuisance calls.

I don't think, however, that knob-fiddling (with the service controls on the back of the chassis) was anywhere near as much of a problem with heavy console color sets (such as the fabulous 3-way entertainment centers all major TV manufacturers carried in their product lines from the '50s to the '70s) as it was with table models or portables; in fact, I think it was almost nonexistent with these huge sets. Once these large consoles were installed in the customer's home, they almost always stayed in that location (unless the customer moved or the set was serviced) for years or decades, the service controls thereby being totally inaccessible to the customer.