I cant read the part numbers, but there are some smarts on the board. Those appear to be GALs or PALs or perhaps something else. The easiest way to get it working would be first to see if there are any labels anywhere on the signals, maybe at the chips, perhaps at the header. Figure out where power and ground are (those are easy to ring out from the chips), then you can just start trying different things to see if you can get anything to happen. Perhaps assume one is a clock, hold the others high, see what happens. Depending on what you find, you might need a scope or analyzer to figure out what is going on. Alternatively, see if you can read off some of the part numbers from the chips.