It's a bit of a long stretch to call this a scope but, when I was young ( A long time ago and Valves) we used to use an audio amp to listen to the buzz on TVs. We could hear the frame buzz and you could hear the difference in picture content too.
I had an old Radio that I took to pieces and stuck a 0.1 cap on the top end of the vol pot with a bit of stiff coax as my probe. After attaching it to a voltage - I should not have done, it fried things a bit. The thing with sound is you do not have to look at the screen while you are probing (said Paul!) so if you are trying to see if there is pulsed data coming out of you circuit, you may hear the spaces (not the fast data) and you can follow this through.