Texas Instruments TI-99/4A
Computers in Collection
General Notes
Joysticks
Do your joysticks not work in the “up” direction? Turn off the “alpha lock” key! When the “alpha lock” key is pressed down, it’s like holding down the “shift” key. And the “shift” keys are on the same keyboard scan line as the joystick “up” signal. There are other keyboard scan lines that interact with the joystick, but none lock down the way the “alpha lock” key does.