TV Tech Basics: Oscillators vs. Multivibrators

[AlanInSitges]

I hope I'm posting this in the right place.

We have a lot of really experienced people on this forum, many of whom have probably an enormous amount of knowledge about the circuits and technology inside these old TVs. I am not one of these people. While I worked as a kid in a TV repair shop, most of my experience was practical and I didn't really learn any theory or much troubleshooting beyond "if there's half a picture, replace one of the output transistors on the vertical module" type stuff.

Now that I have picked up the soldering iron again and have started collecting some vintage sets that I find interesting, I want to learn more about what's inside. I've got several of the books recommended here on VK and been reading them, and learning quite a bit, but there are still some gaps and questions.

In particular I'm curious about the difference between the use of an oscillator or multivibrator circuit in different sets (talking about the vertical section in particular, since that's what I'm stuck on right now). Why choose one over the other? Why is there sometimes a blocking transformer and sometimes not? And how do you get from a sine wave produced by an oscillator to the sawtooth-ish thing needed to drive vertical sweep?

Would one of you smart guys mind doing a brief discourse?