This was a pretty satisfying project.  I learned how those small three-terminal switching supply modules work (basically like the linear regulators, but without the inefficiency), and I resurrected an otherwise dormant machine.  I still have it in my collection, but I have zero software for it.  Maybe I'll find some someday.  

In the meantime, I want to try to interface an old period-correct SONY cassette deck to it, so I will at least be able to store and retrieve programs.

Incidentally, I retained all the original parts, so future owners will be able to restore the TI to its original stock configuration.

Happy retro-computing!  Press any key to begin!