Strange fault in Zenith radio!

[radiotvnut]

You could have defective IF transformers. IF transformers from the immediate post WWII era until the end of tube radio production in the late '60's often suffer from "silver migration". What happens is that the capacitors that are imbedded in the base of the IF transformer leak and cause current to flow from the primary side to the secondary side of the transformer. This action will cause the static burst that you describe. There are ways that the old embedded caps can be eliminated and modern caps can be substituted. The process looks to be tedious; but, is often the only way, since these older IF transformers are hard to find now. I have not personally replaced the caps in an IF transformer; but, I've got a '52 Philco that I'm about to try my hand at repairing the IF's.