When buying boards from people to either part out or repair, one question that comes to mind is "What is it?"
There are several ways to identify boards, Konami puts information on the silk screen printing that makes it easy to Google for the ID. Other boards have labels on the ROMs that either tell what the game is, or can be used in a Google search to find the name.
Others can be quite a bit tougher. No names on the boards, no labels on the ROMs, and no other clues as to what the board is. For these, you'll want to use an EPROM programmer along with the ROMIDENT utility. Simply read the ROM chip in the programmer, save it as a raw file to the directory where ROMIDENT is, then run ROMIDENT against that file to identify the game.
But, what if ROMIDENT can't identify it? Simply take the 32 bit checksum value output by ROMIDENT and run that value through Google. If the ROM has been dumped as part of the MAME project then you'll find it and the identity for the unknown board.
ROMIDENT can be found at:
http://www.system16.com/romident.php