If I run the command line version of MAME without any parameters, and navigate through the menu that comes up, I can load and run TI 99 games just fine.
If I try to use Launchbox to run them, it just opens a black screen then closes right away.
I have added MAME as an emulator, and I have added TI 99 as an associated platform, put "ti99_4a -cart" into the Default Command Line Parameters, and checked it as Default Emulator.
Any ideas? I can't see what MAME is doing under the hood when I use its built in menu to launch games, so I can't replicate it. I'm guessing something is wrong with the Default Command Line parameter line.