Been watching you guys.... That scope will be fine for what you are doing.... Main thing is that you will be connecting that ground lead to some ground (metal chassis part) on your tv. Before you connect it, take a volt meter AC 250v scale, and connect one lead to the ground on your tv, and the other lead to the ground lead off the scope... If you read a voltage... like 120v then you need to reverse the plug in the wall off one of your items, as you have a hot chassis on those items.... Then measure it again, the voltage should be gone, or very low... If there was no voltage to begin with then don't worry about it.
Anyway, your just looking to see that the pulse is getting through. 30v at 15,734hz and 30 at 59hz. That scope will show it to you fine.
The sweep rate 7875 and the other one are Sam's own favorite rates they always print those numbers, its just so they can show a few frames of the recurring pulse.... It will be 1/15734 the horiz scan rate, and 1/59 hz the vert. refresh rate....
A few pretty good oscilloscope tutorials:
Oscilloscope 101 if it don't put you to sleep:
http://www.youtube.com/watch?v=WiNpGZaJArA
If you had a modern scope you could measure DC like this:
http://www.youtube.com/watch?v=vFqxn6VGYC0
Signal measuring & frequency:
http://www.youtube.com/watch?v=zQDuZ3a6HAE
Here is a cool thingie about bandwidth:
http://www.youtube.com/watch?v=oZ1Dv2dVGkU
Here's something you'll never need....
http://www.youtube.com/watch?v=pGwL6FadC9U
ok, I spent too much time on youtube today.....
Lots of really good electronics stuff on youtube.......