Masked ROM - U29 on main logic board (Rev A.01.02) - NOTE: replace EPROMs (40-pin) U4, U9, U28, and U29 with New masked ROMS (42-pin) in U28/U29 sockets and leave U4/U9 empty
1818-6521Masked ROM - U28 on main logic board (Rev A.01.02) - NOTE: replace EPROMs (40-pin) U4, U9, U28, and U29 with New masked ROMS (42-pin) in U28/U29 sockets and leave U4/U9 empty