I remember this quite well. I am considerably beyond the age you mention. This actually brings back fond memories (even the annoying sound test). When I was 10-12 years old I spent many evenings after school at the home of a neighbor who had a TV and radio repair shop in the basement of his home. He very graciously allowed me to "help" him. I can still picture the inside of a TV cabinet . . . a very large (and very heavy) picture tube, a lot of glowing, humming vacuum tubes and lots of very disorganized looking wires. Also, by today's standards there was a lot of empty space. There seemed to be a whole lot more "nothing" than there was "something" inside a TV cabinet. This was the beginning of my love for the "magic" of electronics.
Also, he had two daughters who were quite easy on the eyes.
Chuck