Texas Instruments TI-99/4A

Resources

Wiki
oldcomputer.info (pinouts)
99er.net
Robots & Computers (pinouts)
TI Game Shelf (game disk and tape images)

Internals

Motherboard

Power adapter board

Keyboard

Reassembly

Loading games

Unlike almost all other machines, this one needs a special “Assembler/Editor” cartridge in order to load non-basic programs. There seems to be no workaround for that.

For basic programs, the command to load it from the tape is (again, unlike anywhere else):

  • OLD CS1

And it won’t work if you enter cs1 in non-capital letters.

It is fairly easy to attach this machine to a PC and replay programs from wav audio files. Pins 8 and 9 on the back joystick-like port need to be connected to an audio jack going to the PC. Pin 9 (bottom row, rightmost) to the ground and pin 8 to the audio signal.

In order to convert images to audio files, please follow instructions from the oldcomputer.info page in “Preparing tapes” paragraph.

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