In the 1970s almost all TVs were hot chassis types, that is one side of the AC line was the entire electronic system ground. The antenna was transformer coupled. We did have polarized plugs in the 70s and UL required no exposed screws be connected to the chassis ground. But who knows? And even with a polarized power plug, how many older outlets are wired properly? Black to silver and white to brass - right!
Today switch mode power supplies are used which is offers the same isolation as a 60hz power transformer. Kinda need that with all the grounded input and output jacks in use today but on those days before VTRS and home theater, all you ever connected to a TV was an antenna.
Now growing up I inherited an old 1950s transformerless tube GE portable TV in a metal case with one side of the AC line grounded to it. What were they thinking? I guess on the family room table with no other grounded metal within reach it was safe! And what idiot would put it on a kitchen counter? At least that was 1950s thinking.
[This message has been edited by Gus99 (edited 11-02-2006).]