Does anyone know if the TI-99/4a requires a special kind of joystick?
I've tried with an atari joystick and also a Wico joystick, but it doesn't seem to work.
I thought at least the atari one would work, but there's of course a chance it's the joystick that's broke.
I believe that the joystick socket is wired differently to the Atari joysticks so you need an adaptor that "rearranges" the wires.
The Atariage forum has a section for the TI 99/4a and will be able to give you a much more authoritative answer.
Yes it's different from the Atari standard. See here:
http://www.atarimagazines.com/compute/issue39/HOW_TO_BUILD_YOUR_OWN_TI-99_4A_JOYSTICK_ADAPTER.php (http://www.atarimagazines.com/compute/issue39/HOW_TO_BUILD_YOUR_OWN_TI-99_4A_JOYSTICK_ADAPTER.php)
The single adapter could be easily made with a single sided PCB. I made a batch of similar adapters for the Spectrum +3. The dual adapter needs a second layer, however, both are simple enough to just "free-wire" them.
Bryce.