My attempt at an Intellivision RGB board

[Diederikgr]

So for my study in electrical engineering I had to design a single pcb, but I actually ended up designing multiple. The first one was an RGB board for the Colecovision that converted the analog video signals into RGB. With the schematic I built it from being quite sketchy, I'll only share it if it delivers any decent results. The second PCB is one I'm a little more confident with.

 

There used to be a board like it called the Zoe (kinda wanna call it the Joey), but it was apparently a tough one to get. I also didn't like the idea of soldering 10 wires to the PCB. My idea is to imitate what Tim Worthington has been doing with the NESRGB and 2600RGB boards, where the modboard sits in the socket of the IC it takes the signals from while still leaving the IC functioning the same. This method is more work, especially if the IC isn't socketed to begin with, but leaves a much more tidy result. I also went with SMD components over through-hole as this allows for a smaller PCB, although it may scare the hobbyist away from it. The three IC's will be tough, but the other components should be easily doable with a soldering iron. The board also houses an additional pin header to do a composite video mod, which will require soldering a single cable to the Intellivision's board.

 

Considering this is just a 3 bit DAC (times 3) I also tried making it with Opamps, but wasn't succesful in simulating anything functional. I didn't want to include a negative voltage on the board to use different opamps, and couldnt get anything working with single supply opamps. I'm not an electrical engineer quite yet, so my attempts only take me so far.

Edited December 19, 2018 by Diederikgr

[mr_me]

Very nice. So this plugs in place of the ay3-8915? How are the colours defined.

[+BBWW]

I'm clueless on the engineering but know I want an Intellivision with RBG out LOL. HDMI would be sweet in a modified Intellivision as well.

[Diederikgr]

It plugs in place of the LM1886 on PAL models only. Developing an RGB board for the NTSC variant is a different beast entirely as I don't think there's anywhere to pull digital RGB signals from.