I recently look for TI-99/4A schematics and found the usual material on WHTech FTP-Server. But these schematic diagrams are not very useful. They contain errors, are badly readable and you can't do nothing else than watching them. Unfortunately I can't find any digitally captured schematics, so I started to make some new by myself.
The first schematic I redraw was the one of the TI console. I took this original as a template. Currently this schematic could contain more errors than the original, because I can't decipher all the small printed and unsharp displayed values and reference numbers of the components correctly. But it should be possible to generate or design a new PCB from it.
With this work I also try to separate some function blocks into its own schematic sheets. So the schematics for the console is split into multiple files:
- Keyboard (with Joystick and cassette port)
- 8 to 16 bit switch, which generates the A15
- GROM logic
- I/O Ports
- internal address decoding
My work is published in a new repository on the well known git hoster bitbucket. All schematics are (and should be) created with the KiCad EDA, a cross platform and Open Source Electronics Design Automation Suite.
I hope here are some people who are willing to support this activity.
Edited by HackMac, Sat Oct 10, 2015 2:22 AM.