Atari 2600 (4 Switch) Composite & Other Mods
When it comes to retro video games Atari is about as classic as you can get. But if you dug out an Atari from your grandparent’s basement or picked one up from a retro store you’re immediately faced with the conundrum of how to hook it the antiquated RF video connection on a modern TV. Even if you have coaxial connection on your TV or set top box you’ll be fighting to get a clean signal. On top of that modern televisions tend to be very dark in displaying many Atari games making them harder to play.
Luckily getting composite (A/V) output on an Atari is an easy modification. All it takes is some rudimentary soldering skills, a few components, and an afternoon. There are kits you can buy to make this even easier but if you’re an electronics hobbyist you probably have these parts laying around.
Note: This is for 4 switch NTSC Atari 2600 models.
- 2.2k Resistor
- 3.3k Resistor
- Another resistor between 60-100 ohms. This is entirely optional but can help keep the composite output from being too bright.
- 2n222 NPN Transistor
- 100uf Electrolytic Capacitor. Also optional but can help to smooth out noise and stabilize voltage
- Jumper wires
- 3 RCA connectors
- Perf board cut to size
- 12+ feet of 3 RCA (red white yellow) cable. This may be longer or shorter depending on how far you sit from your television. Atari was designed for the actual console to be close to you.
- Soldering Iron
- Flush Cutters
- Tweezers or needle noise pliers
- Desoldering wick or a desoldering tool
- 1 small drill bit for pilot holes and a 1/4 inch drill bit
- Tape – Painter/Masking and electrical
- Hot Glue
Let’s Get Mod’in
What we are aiming to achieve is to remove the RF module from the Atari, replace it with a circuit that will provide composite output, wire that signal to some RCA jacks, and we’ll throw in some bonus mods while we’re at it.
We’ll start with the new composite video circuit.
This is a very easy circuit to construct, just line up your parts accordingly on the perf board taking careful note of the capacitor (electrolytic’s are polarized) as well as the base, collector and emitter of the transistor. Solder them to together using the component leads to create pathways, jumper wires, or solder bridges. Make sure you leave openings for wires that will carry the ground, 5v power, video in and video out.
Next we take apart the Atari which is as simple as removing the four screws at the bottom. Save the screws aside and carefully lift the lid, you’ll have to lower the toggle switches out while also sliding out the controller ports. At this point you can also unplug the RF cable from the main circuit board and remove it from the case.
On the board we’ll focus at first on the RF module and little circuit board attached to it with five pins going into the Atari’s main board. You have two options here.
- Carefully desolder it all and remove it in case something goes wrong or you have other reason to undo your mod.
- Cut everything out with cutters and then remove the remaining component leads and solder using your pliers, flux and soldering iron.
Either way you choose remove the RF module and circuit board (circled red below).
Next move on to the large metal square shield in the middle of the board. This is the RF shield and will no longer be necessary. To remove it twist the 4 metal tabs on each side to line up with their slots. The top piece should lift off and the bottom piece should also pull away from the main board. Do this carefully, if it’s not coming out easily re-twist and line up the metal tabs.
Next to the tall red coil cylinder there is a transistor, most likely labeled Q201 or Q202. It is optional to remove this but if you do it can increase signal quality. You also need to remove a resistor labeled R208. I removed both in my mod. Again you can choose to desolder or cut it out using cutters.
Wiring Up the Composite Circuit & Audio
With all the components removed its time to wire up your new video circuit, audio and RCA connectors.
Firstly we’ll place the new composite circuit in the left over gap where the old RF module used to be.
Where the RF module circuit board was there will be five via’s. The far left is ground, the third is +5v, and the 4th is your video signal. The 2nd and 5th we are not using. Wire the appropriate cables from there to your new composite circuit.
Finally wire a longer output wire that will reach to the back of the Atari. I recommend using much longer than you need so you can play with placements and have a margin for error.
I used a screw terminal on my composite circuit but you can just as easily solder them in. To be extra safe I placed thicker rubber insulation below the circuit and hot glued it all in place.
Next came the RCA jacks. I chose to center them on the back panel but you can place them anywhere you like. Atari’s plastic is very brittle! Be careful when drilling! Put painters or masking tape on the case and mark where you want the holes. Start with a thin pilot hole and gradually step up the drill bit sizes until you get a 1/4 inch hole. You can also use a step drill bit if you have one.
I’m a little bummed I couldn’t get all matching RCA jacks but its what I had laying around.
When wiring up the RCA jacks pull ground from any source on the main board or your new composite circuit and share it among all the jack’s outer ring. After that you’d wire up the video line to one of the RCA’s center post. The audio wire you’ll solder to both the remaining RCA’s center posts. Atari doesn’t output stereo, so essentially this setup gives you dual mono.
While I had the main board accessible I also installed an LED light as a power indicator. I drilled a small hole the size of a standard LED near the power switch and using a red LED (red seemed to matched the aesthetic better) with a 1k resistor on the cathode soldered it to the 5v regulator located on the left side of the board. Hot glue held the LED in place and I used a connector so if I serviced the machine again I could easily disconnect it from the board without desoldering. Always build things you can take apart!
Testing and Finishing
Before putting it all back together test out the video and audio outputs. With this mod you get a black scree instead of a static/noisy screen if the game doesn’t load which can easily make you think something is wrong. Before you troubleshoot further try reseating or resetting the game or a different game cartridge.
Once you verify sound and video are working dial in any color adjustments using the potentiometer on the left hand side of the main board (circled below). Pitfall’s various shades of green along with blues, reds and other bright colors make it a great game for color balancing.
If you find your image is too bright or too dark consider changing the pull down resistor attached to the emitter of 2N222 Transistor. A lower value will be brighter, a higher value will be dimmer.
Another great mod done but not pictured is installing microswitches to the controllers to make them more responsive. A tutorial to that mod can be found here https://www.youtube.com/watch?v=WdIerqiYfA0
These are all easy mods that extend the life and use of your old Atari. Good luck!