Sega Master System

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Chip Info

837-6067 M4 POWERBASE/NTSC


837-6629 (Ink stamped 837-6097) M4 POWERBASE/NTSC


IC BD M4Jr. PAL 2M (171-6395A)


Capacitor Lists

1986 MS POWER BASE/NTSC, 171-5379

See 837-6067

SEGA M4, POWERBASE/NTSC, 837-6067 & 837-6405

Purchase these parts as a kit

SMS PCB 837-6067
CA1	10uF	16v
CA20	100uF	10v
C1	10uF	16v
C4	100uF	10v
C20	100uF	10v
C22	100uF	10v
C25	100uF	10v
C28	100uF	10v
C49	10uF	16v
C119	10uF	16v
C120	10uF	16v
C121	10uF	16v
C122	47uF	10v
C123	47uF	10v
C124	47uF	10v
C131	10uF	16v


SEGA M4, POWERBASE/NTSC, 837-6629

Purchase these parts as a kit

SMS PCB 837-6629
CA1	10uF	10V
C1	100uF	16V
C4	100uF	10V
C20	100uF	10V
C28	100uF	10V
C37	1uF	50V
C49	10uF	10V
C51	100uF	10V
C119	10uF	10V
C120	10uF	10V
C121	10uF	10V
C122	47uF	10V
C123	47uF	10V
C124	47uF	10V
C131	10uF	10V


SEGA IC BD M4Jr. VA1, 837-7275

Purchase these parts as a kit

C1	47uF	10v
C2	10uF	16v
C50	100uF	16v
C53	100uF	10v
C54	100uF	10v
C62	1uF	50v
C71	100uF	10v
C73	47uF	10v
CE	10uF	16v
CE	10uF	16v
CE	10uF	16v
CE	10uF	16v
CE	10uF	16v
CE	10uF	16v


Schematics

SMS: IC BOARD PB PAL VA1 (171-5534)


SMS2: IC BD M4 JR PAL (171-5922A)

SMS2: IC BD M4 JR RGB (171-5926)


Service Manuals

Sega Master System Service Manual

Sega Master System II Service Manual, April, 1991


BIOS Replacement

837-6067 Compatibility

In my experience, the -6067 is only compatible with the v1.3 BIOS. Sega seems to have revised both the hardware and BIOS for -6629 PCBs. BIOS versions 2.1 and later will not correctly boot on -6067 hardware.


Changing jumpers for larger BIOS ROMs

The SMS BIOS can be replaced with a standard EPROM, but a small modification may be necessary to enable a 256kB EPROM. By default, A14 at the BIOS is tied HIGH. Using the pics below, you can reconnect A14 to the system bus.

6067 PCBs

6405 / 6629 PCBs