I'd be checking that the 5VDC is stable - A multimeter across the power supply and then the edge connector at the board.
Re-seat the ROMs on the board.
Remove the edge connector from the board and rub the connector (at the board) with a pencil eraser. Re connect the edge connector and test.
If the board has failed, then I'd buy a 60 in 1 - but the cabinet would have to be re wired to Jamma as described.
