Polarized AC plug on sets with a VRT

[zeno]

The common reason antenna jacks went hot was there is
an isolation unit on them. There was a common one used
in Jap sets that would often get hit with lightning &
get blackened or blow apart. Almost always when on cable box.
That gave a solid path to ground. The newer the set the more
extensive the damage, often a total loss.

73 Zeno
LFOD !