The Namco Galaga is an 8-bitarcade gamesystem board which was first used by Namco in 1981; the fourth and fifth titles to use it, Xevious and its 1984 update Super Xevious, were also modified to support a 129-color palette.
Namco Galaga specifications
Main, graphics and sound CPU: three Zilog Z80 microprocessors, 3.072 MHz
Sound chip: Uses the same custom three-channel WSG (Waveform Sound Generator) as the Namco Pac-Man hardware.
Other chips: Custom input/output controller (type 1) which handles the controls. Bosconian also has a second input/output controller (type 1) which handles the speech (from a Namco 54XX DAC).
Video resolution: 224 x 288 (Bosconian, like Rally-X and New Rally-X, has the monitor in a landscape orientation. The other games are portrait.)
Notes: Each of the five games uses a different video board (except Xevious and Super Xevious, which use the same one).