four tubes used in the Chromacolor "4 tube hybrid" on the steel chassis. Zenith began using circuit boards in radios when they converted to solid-state in the late 1960s, but even Zenith's early transistor radios were completely hand wired with socketed transistors. Due to the use of this chassis construction (and the high quality components), Zenith televisions and radios of the 1950s to 1970s found today are often still working well, needing little work to restore them to like-new operating condition. See also Zenith (disambiguation) References External links 1918 establishments in Illinois 1995 mergers and acquisitions Amateur radio companies American companies established in 1918 American subsidiaries of foreign companies Companies based in Lake County, Illinois Companies that filed for Chapter 11 bankruptcy in 1999 Consumer electronics brands Electronics companies established in 1918 Electronics companies of the United States History of radio LG Electronics Melrose Park, Illinois Radio manufacturers