You need a known working setup to test it with. That could be a working cabinet or a workbench setup.
Alternatively, if all the roms/rams/cpu test good, there's a good chance the board is good. If you're looking for a way to look at a board and have it tell you if it's good or not... sorry.
EDIT: Also, if you have an oscilloscope, you could probe the video outputs to see if it's doing anything. Use a multimeter to check power supply voltages first.