[Jeffhs]

The Zenith 19" portable you picked up reminds me of a similar set used as a video monitor in my high school's CCTV system 40+ years ago; it (and almost certainly the rest of that system) is long gone by now, almost 40 years since my class graduated.

Your set looks like it is missing the channel selector knob, but if you can set the tuner on channel 3 or 4, even if it means using a pair of pliers to do it (!), you won't need the knob anyhow since any DTV box or cable box you connect to it will have an output signal on one of those channels. Being near Buffalo, you would probably use channel 3 as the output channel, but since all TV is digital these days it probably wouldn't matter which channel you selected to receive the output of the converter or box. Even if you use channel 4, the signal from the box would more than likely override the broadcast signal, since the former will be fed directly into the tuner via coax.