Page 4 of the schematics at http://www.ipdb.org/machine.cgi?id=1416 has the row/collum information.
Disconnect the playfield and test using jumpers to determine if you have a board problem or a playfield wiring problem.
http://www.pinwiki.com/wiki/index.php?title=Data_East/Sega#On_Board.2FOff_Board_Switch_Matrix_Problem_Determination