[Jeffhs]

Many older (late 1940s-early '50s) large-screen TVs used 30 or more tubes. Remember, commercial television was just getting started at that time. I don't know if there were any such things as multi-function tubes in those days, so it may have been that the manufacturers were forced to use one tube for each function of the TV. I think the very early RCA color sets (CTC3, 4, 5, et al.) had at least 30 tubes; some sets may have had more, as did the early color sets from manufacturers such as Arvin, Westinghouse, et al. The tube counts didn't start decreasing until multi-section tubes were developed.