Ninja, thank you very much for posting this video.  While it is really outdated, it was just enough nudge in the right direction to get my trackball working.  Not only did I get the trackball working for Centipede, Millipede, Missile Command and even Tempest, but I was able to configure Robotron to use the second joystick for firing just like the original arcade machine.

Thank you again for your help.  It was a game changer (pun intended).