Texas Instruments TI-99/4A (1981)


Texas Instruments TI99/4A

Very uncommon here in Italy, this system was quite successful in the US in the early Eighties. I thank Ciro from the TI99 Italian User Club for having helped me to find a TI-99/4A in good condition: the metal of the upper case can be scratched very easily.


Texas Instruments TI99/4A - views

Ports on the back: tape recorder, power supply, and video. On the right side the expansion port, and on the left side the joysticks (“wired remote controllers”) port.

The computer didn’t need to be cleaned as usual, but since I’m curious to see “how it’s done” and to create the teardown image, I took it apart. Nothing difficult, but it took more time that other machines of the same period.

Texas Instruments TI99/4A - teardown

The motherboard…

Texas Instruments TI99/4A - motherboard

…and the power supply board.

Texas Instruments TI99/4A - power supply board

The power supply is external.

Texas Instruments TI99/4A - power supply

The power supply connector:

Texas Instruments TI99/4A - power connector

Here’s the modulator to connect the computer to a TV.

Texas Instruments TI99/4A - modulator

The cartridge (“command module”) port is at the right side of the keyboard; the photo shows the TI Invaders one, a Space Invaders clone.

Texas Instruments TI99/4A - TI Invaders

This computer was assembled in Italy and there are all the manuals in Italian.

Texas Instruments TI99/4A - manuals

The TI-99/4A is a beautiful computer – from an aesthetic point of view. But the lack of a serial port forced the users to buy expensive external interfaces to connect peripherals such as floppy drives and printers. Other contemporary home computers (most notably Atari and Commodore competitors) offered a serial bus where you just had to buy the peripheral and connect it with a simple cable.

Texas Instruments TI99/4A

One thought on “Texas Instruments TI-99/4A (1981)

  1. Xenfomation

    That is gorgeous machine! I have two in perfect working order, however my original power supply exploded: the 120 vDC -> AC Current transformer took the brunt and the machine was okay. Now I am stuck with trying to find the actual Amps as to bypass the power supply board and pipe in the +5V, +12V, and -5V for direct power.

    Love this site, by the by. I took am setting up my office to house this marvelous machines.


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