171-6416A Board Info

This is the final board revision for the Sega Master System II sold in France, and is a very slight revision of the previous board used in those consoles. Introduced in mid-1993, it changes out the original 28-pin 1 megabit (128 kilobyte) BIOS ROM for a 32-pin 2 megabit (256 kilobyte) ROM, which has Sonic the Hedgehog as the built-in game. Resistors R1 and R2, previously placed near the BIOS, were moved to the left-hand side of the CPU to make room for the physically larger ROM. Aside from these changes, it is identical to the revision it replaced, and even still has the footprints for a CXA1145 video encoder, RF modulator, and their associated support components for an NTSC variant. By this time, the Master System had already been discontinued in NTSC regions so these components were left unpopulated on every one of these boards produced.

All boards have the silkscreened text SEGA IC BD M4Jr. 2M at the lower left corner. Sega did not add an "837-" part number as was typical for assembled PCBs.

Parts List

All resistors are 1/6 W.

Because this retains all of the component footprints from the 171-5926A, it is possible to fully convert a console with this board into an NTSC console by repopulating the omitted components and making some slight changes. Values for these unpopulated components can be found on that board revision's page.