This is a Texas TI-99/4A home computer released in 1981.
I have had this one for like twenty years or so, but never used it.
(Got it from a friend that never used it either. 🙂 )

It is working, but just had RF output via an external RF box.
(It uses a 6-pin DIN that puts out component video, Red, Green and Blue.)

But since i want to use composite video, i had to do a mod. 🙂

There is a mod for the external PAL RF modulator, model PHA 2036.
It makes it possible to add one composite RCA connector and an audio RCA connector.

It was an easy mod, i just drilled two holes for the RCA’s and soldered three wires. 🙂
The description of the mod said nothing about insulating the RCA’s from ground though.
After beeping out ground vs video ground, i noticed that they were not connected.
If i just mounted the RCA’s as they were, the ground and video ground would be connected.
So, i isolated the RCA’s from ground with some electrical tape, just to be sure.

After this, the composite video worked, but i still have to see if the audio works.
I have never used a TI-99/4A before, so i have to figure out how to get it to produce sound. 🙂

Next step will be to try to get it connected to my PC to see if i can get it to load a program. 🙂