How do I get composite video from my 6-switch Atari 2600?
A pleasant task indeed!
To get composite video from an Atari 2600, you will need:
A 22-ohm resistor.
Two 1-k potentiometers.
Solder and a soldering iron
RCA phono plugs (the kind you plug video cables into)
The components to get composite video hook up to the same spots on the Stella chip on all three model Ataris. But in each model, the Stella chip is in a different position, so the pins aren't in the same place all the time. Also the CHROMA lead is in a different place on each model.
Look on the right-hand side of the 6-switch Atari 2600 board. You should see some resistors and things like this:
Hook up wires to these 2 points. If you need to double-check, flip the board over and make sure the resistor or capacitor and capacitor numbers are correct. Now you have the audio and chroma connections.
To make audio work, connect the spot marked "Audio" to the center tap of an RCA phono plug. Then, connect the outer edge of the RCA plug to the ground of the Atari board. To get ground, connect it to any spot on the Atari circuit board that touched the metal shield. (anywhere on the metal band that goes around the edge of the circuit board)
Take a look at this. Here are which pins are which on the 4-switch Atari 2600's Stella chip.
Here is a super-high-tech schematic of how to hook up the rest of the video.
I will explain it in detail. Connect some wires to pins 5, 7 & 8. Attach each of those wires to the appropriate item;
Pin 5 goes to a 1 k potentiometer. Pin 7 goes to a 22-ohm resistor. And Pin 8 goes to a 1 k potentiometer.
Then, connect the other end of each potentiometer to a common wire, labeled spot "A" on this diagram. Connect Pin 2 to spot "A" as well. (Pin 2 doesn't need a resistor or anything on it, it's just video sync) Connect the "Chroma" wire to spot "A" also. Now you have composite video!
To make it work, hook the composite video lead into the center tap of an RCA phono plug. Now attach a wire to the outer side of the RCA plug. This will be ground. Connect it to any spot on the Atari circuit board that touched the metal shield. (anywhere on the metal band that goes around the edge of the circuit board)
Now if you plug in a video cable and attach it to a monitor, you will have VIDEO! Yahoo! Adjust the potentiometers until the video looks right. Use a game like Pitfall that has a lot of color for a good calibration.