Description

About the Kit:

This listing is for one bare PCB and edge connector. Once you purchase the remaining parts yourself, you can use this PCB and edge connector to build yourself a brand new Texas Instruments TI99/4A Sidecar Memory Expansion Card. This kit only includes the parts shown. The remaining parts you'll have to source yourself. You will obviously need to be handy with a soldering iron to complete this project. This listing is meant for those who want to experience the build themselves.

Once constructed, here is some information about the completed memory expander:

This is a 32k memory expansion for the sideport of the vintage TI-99/4a personal computer. Functionally equivalent to TI's 32k expansion ram, this device plugs into the sideport of the TI with an edge card connector. It operates with +5v, using about 5-10mah either drawing power from the computer or through the external power jack when plugged into a 5vdc power supply (not included). Selection of either configuration is performed by setting the desired jumper configuration (found on the board) to either take power from external 5.5/2.1mm tip-positive power jack, or the TI-99/4A sideport.

With this device plugged into your TI99/4A a user can run many of the games on the 2048k cart or any of the 6 multicart games cartridges. Many of the newer cartridge titles also require a 32k expansion and will work with this device.

This memory expansion will function with the TI99 Speech Synthesizer, however the TI-99/4A speech synthesizer does not pass power on pin #1. This means that the memory expander cannot draw power from the computer to power itself (unless the power jumper modification has been performed on your speech synthesizer). The work-around is simple however. Get yourself a 5VDC power supply and operate the memory expander on external power when plugged into your speech synthesizer (or modify it yourself to pass power).

What you get:

Again I want to be very clear that you receive the bare PCB and the connector in this kit, nothing else. Use Google to search the internet for this device, and you'll find all sorts of information on it.

BOM:

Here is the bill of materials for the parts you''ll need to obtain to complete construction of this device.

Cypress 32k SRAM

74HCT245

74HCT138

74HCT21

IC SOCKET 20 PIN

IC SOCKET 14 PIN

IC SOCKET 16 PIN

IC SOCKET 28 PIN 0.6"

4x 0.1uf ceramic decoupling capacitors

2x 1k ohm 1/4 watt resistor