Disclaimer: I am not responsible for any damage done to your Atari. This mod is designed to remove the RF output. The mod will work if performed correctly to a fully functioning Atari. Perform at your own risk.
Turn the Atari over and remove the 4 screws. Set them aside for later. Remove the main board out of the console by disconnecting the RF cable shown below. Take off the black foam covers on the switches and set them aside for later. Take the foil tape off the switches and throw it away.
Using the need nose pliers, bend up the 4 tabs around the metal case. Remove the metal casing (top and bottom) and throw it away. You should now have the main board like this ready to modify.
In the middle of the board is a transistor you will have to remove. It is labeled Q201 on some 4 switch versions and Q202 on others. It’s shown in the picture on the left. Simply cut all 3 leads of the transistor and throw it out. Make sure none of the leads coming out of the board are touching each other. Then you need to remove the 4 pins to the RF modulator (metal box with small circuit board attached). Simply cut the pins and bend them up so they are out of the way, or you could break off the small circuit board entirely because it is no longer used.
Now it’s time to assemble the circuit board. Just follow the picture below and solder in the transistor, 2.2k Resistor (Red-Red-Red), and 3.3k Resistor (Orange-Orange-Red). The components are labeled on the circuit board so it should be pretty easy to see where they go.
You should have two pieces of 4 conductor wire. First, strip off the white sheathing. You can save about an inch of it to help group the wires together if you like. Next, throw out one of the yellow wires. Now you should have two groups of wires. A group of 3 output wires (Red, Black, and Blue), and a group of 4 input wires (Red, Black, Blue, and Yellow). With the new wire I use, Blue replaces Green and Yellow replaces White in the pictures. The group of 4 wires are the input wires that go to the main board. Strip about 1/2″ off of both ends of the input wires and attach them to the mod kit. Black is the GND, Red is +5v, Blue is Video, and Yellow is Audio.
The group of 3 wires are out wires that attach to the RCA jacks. The output wires should be stripped to different lengths as in the picture. About 1/2″ for Blue, 1″ for Red, and 2″ for Black. On the output side of the mod kit, Black is for GND, Red for Audio, and Blue for Video.
First you need to use your de-soldering tool and clean out the holes where the RF modulator pins were. Then connect the input wires and solder them in from underneath as shown in the picture. Make sure the black wire goes to pin #1, red to pin #3, and blue to pin #4. Then attach the yellow wire to the base of the resistor as shown (R206). You could also use the open hole on the capacitor immediately to the right (C208), as they are connected to each other. Now the main board is done.
Take the bottom half of the case and put a piece of masking tape where you want the RCA jacks to go. Use a ruler and marker and make 3 dots on the tape 1/2″ apart. Then drill 1/8” pilot holes on the dots, and use the 1/4” drill bits on the holes to make them ready for the RCA jacks. The tape and marker are just extra precautions, you could also just drill the holes if you want.
Attach the RCA jacks by mounting them into the case with the ground ring and nut on the inside. Make sure they are tight. Have the ground ring holes be at or near he top and bend them down to make soldering easier. Take the Black output wire with the longest amount of bare wire and solder it to all three ground rings like in the picture below. Take the Red wire and solder it to the Red and White jacks. Take the Blue wire and solder it to the yellow jack.
Now you are ready to put the mainboard into the case. First you need to adjust the color pot on the bottom left of the mainboard. Attach the RCA and power cables and use a game with nice bright colors you are familiar with like Pitfall or Frogger. Adjust the pot so the colors are just right. Then peel off the bottom of the double sided tape and stick it to the right side of the bottom case. Replace the foam dust covers, top case, and the screws and you are ready to play your Atari with composite video! Please leave a comment below and let me know how it works!