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Texas Instruments TI-99/4A – 32k Internal Exp. + Status LED + Reset

Texas Instruments TI-99/4A - 32k Internal Expansion Memory + Status LED + Reset

Texas Instruments TI-99/4A – 32k Internal Expansion Memory + Status LED + Reset.

Works that have been made:

  • 32k Internal Expansion Memory.
  • Switch for disable the Expansion Memory.
  • Reset Pushbutton switch.
  • Bi-Color LEDs to display the status of the internal memory expansion 32k. (ON = Green / OFF = Red)
  • Replaced the resistor for the LED from 2.2k to 220 ohms.

Gallery of the works that have been made:

It could be better!

I had severals problems with the free space inside the TI-99/4a, i had to remove one side of the metal part, the biggest problem is the internal 32k expansion which is not very well done, there is no a way to secure it inside … but everything works perfectly :D

  1. rich
    December 19th, 2018 at 22:04 | #1

    is this 32k upgrade based on harmlesslions 32k internal upgrade ? if so where do you disable the 32k ? i need a switch for mine thanks

  2. January 4th, 2019 at 13:56 | #2

    @rich

    Yes, you have to follow the SPCO (Single pole changeover) colors wires and you find the three contacts on the PCB.

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