NTSC Master System: M4 POWERBASE/NTSC 837-6629 - Development

Similar to the 837-6405 but has a provision for a 1 megabit (128 KB) BIOS ROM.

Board Number: 171-5538
CPU: Zilog Z0840004PSC
I/O Controller: Sega 315-5216
RAM: NEC D4168C-15
VDP: Sega 315-5124
VRAM: 2 x NEC D4168C-15
Video Encoder: Sony CXA1145
BIOS: Sega MPR-11459 (US/European BIOS v2.4 with Hang-On and Safari Hunt) or
Sega MPR-11458 (US/European BIOS v3.4 with Hang-On) or
Sega MPR-11460 (US/European BIOS v4.4 with Missile Defense 3-D)
Known Production Dates: July 1988 to November 1988

Photo by dhau