This is a basic RF modulator style composite video board for the Tandy / Radio Shack Colour Computer 2

The channel 3/4 switch acts as a Colour / Mono switch, or you can use a jumper or other switch installed at JP1.

This is a little bit of an involved install, in that you not only have to remove the RF modulator, but you have to extract the MC1372 from the remodulator (or source new ones I guess) and then drill two mounting holes in the system board to mount the stand offs. You can lay the composite board on top of the system board to mark your holes before you drill. Make sure you remove the solder mask under the standoffs, as the composite board is grounding through there.

There were two styles of RF modulator in these computers, and this project is for the style where the RF modulator lays flat against the system board. This circuit is roughly based on a schematic in the Motorola MC1372 data sheet and what parts I had on hand.

The CRT is hard to photograph, but I included a picture. Image looks acceptable to me here, though I suspect it could be improved with some changes to the circuit.

This is free for non-commercial use. You're welcome to make these for personal use or friends for a nominal time and materials fee, but please don't sell them commercially in online stores or on eBay/sell my retro and such.

Thank you.

Happy SepTandy 2024!