What year roughly was this zenith?

[willy3486]

I am trying to figure out about what year a TV was. When I was a teen in the mid to late 70s I had a older zenith. It was about a 21 inch black and white. I think it was a 60s set. It had a metal chassis that was hand wired. The case was all metal. It had both dials on the upper right. The early versions of this type set had a round tuner knob and the latter ones had a single bar like that you turned. The entire case was metal, no wood and no legs. I would love to find one again and a picture. I have did a search but I haven't found it. I want to find one to restore. Does this model ring a bell?