This is the simplest possible way to make a CRT (cathode ray tube) TV into an oscilloscope, it can be done in about half an hour.
-A CRT TV (color may work, but I'm not sure)
-A soldering gun
-Rubber gripped pliers (for safety)
-A screw driver
Step 1: Identify Wires
After undoing all screws remove the cover from the TV.
Inside wrapped around the CRT are two coils of wire, one controls the vertical deflection of electrons, the other controls the horizontal deflection.
Find where these coils of wire attach to the circuit board, and desolder one coil.
Place the cover back on the TV(for safety) and plug in and turn on the TV.
If you see a horizontal line, you desoldered the vertical deflection coil.
If you see a vertical line, you desoldered the horizontal deflection coil.
Step 2: Placing Wires
Desolder the vertical coil if you haven't already and attach extra wire to the vertical coil, this will have to be long enough to come out of the TV so you can attach a voltage source.
Now desolder the horizontal coil, and solder it to where the vertical coil was.
Step 3: That's It
Really, it's an oscilloscope now.
Step 4: How to Use It With Music
I use mine to watch the waves created by music from my mp3 player
First take an old pair of headphones and cut one off, then strip away some of the insulation.
Now you should have multiple exposed wires, one will be slightly thicker than the others and wll have a thin coating of insulation on it - scrape it off.
Attach this wire to one end of the vertical coil, and the small group of wires to the other end.
Now plug it into a sound source, remember your attaching your mp3 player (or whatever) to a giant coil of wire, and there's chance it could break.