Posted Wed Mar 28, 2012 12:58 AM
Since the location of the thread starter here seems to be in Wisconsin, this will work according to the answers in this thread. But if someone who has a European TI 99/4A reads this, you should know that the video output is different from a PAL console, compared to the NTSC version.
For a European version, you can either route the luminance and color difference signals to a modern flat TV monitor, since they often have this sort of input directly available, or you can modify the RF modulator to get the composite video signal out from there. It's created as an intermediate step in the modulator, before the actual RF modulation occurs.