While I'm getting things sorted out, I thought I'd take a moment and talk about another interesting feature of my Zenith. It's probably not that uncommon for televisions of this vintage, but it's just something I had never seen before!
This never actually worked the few times that I did turn on my tv, but got the idea of how this worked using a LED light on my keychain. To make it project the numerals properly, I'll have to do some adjusting. It had a type 47 bulb in there, which seems to work when I power it with a 9-volt battery. I never saw it light while in the television, however.
I wonder why it displays the number "25" when turned to channel "13" ...