Read this first!
TI-99/4 Manual
1037108-2
This is the second revision talking about the 99/4 and the RF Modulator, not about the 13″ monitor,
and not about the 99/4A.
Texas Instruments Home Computer Hardware Manual
Read this first!
TI-99 Infospot
Your place for the TI-99 Home Computer Family, with focusing on internal documentation and the TI-99/8