I recently purchased a TI-99/4a. Well, 2 actually. Both work, but I only have one RF modulator. I ordered a composite adapter, but that hasn't arrived yet. Both work on the RF modulator, but the video output is very poor. The audio seems to be working perfectly. It looks like it can be opened, but I don't want to damage it to find out nothing can repaired, as it is in a nice condition. Are there any capacitors in the RF modulator or anything else that can be serviced?
While not directly answering my own question, this is the solution I ended up doing:
I just ended up buying a composite adapter, which works great. I decided against opening up the RF modulator, as I dont want to damage it. While I can fix various electronic problems, I am not an electrical engineer and I do not want to damage the modulator visually or electrically. Other than being a little fuzzy, it works. Since I dont plan on using it, why risk breaking it? I dont think its worth it. If I ever end up selling the TI-99/4a, the next owner can decide what to do with it.