Actions

Sega Mega Drive/Hardware revisions

From Sega Retro

(Redirected from Mega Drive PCB revisions)
Back to: Sega Mega Drive.
Cleanup.svg
This article needs cleanup.
This article needs to be edited to conform to a higher standard of article quality. After the article has been cleaned up, you may remove this message. For help, see the How to Edit a Page article.

Model 1

Megadrive JPN VA0 Serial No - 98M10036.jpg VA0 (JPN)
Components:
  • M68K CPU: Signetics SCN68000C8N64
  • M68K memory: 2x HM65256BLSP-15 (32Kx8 PSRAM, 150 ns)
  • Z80 CPU: Zilog Z0840004PSC
  • Z80 memory: TMM2063P - 10 (8Kx8 SRAM, 100 ns)
  • I/O chips: Sega 315-5308, Sega 315-5309, Signectic 74LS00N, 74LS161AN, 74F161AN, 74LS74AN (DIP-16)
  • VDP: Sega 315-5313 (Yamaha YM7101)
  • Video RAM: 2x HM53461ZP-12 (64Kx4 VRAM 120 ns)
  • Headphone amp: Sony CXA1034
  • Video encoder: Sony CXA1145
  • FM synthesizer: Yamaha YM2612

Due to a last-minute issue with the VDP in H40 mode, additional clock circuitry had to be added during manufacturing. This circuitry is present on a daughterboard in the center of the PCB, and contains the master oscillator (53.6931 MHz, NTSC), a 74LS74 (dual D-type flip-flops), and two 74LS161s (4-bit counter).

Megadrive VA1 Produced unit 99N83420 (JPN).JPG VA1 (JPN)
Components:
  • M68K CPU: Signetics SCN68000C8N64
  • M68K memory: 2x TC51832SPL-10 (32Kx8 PSRAM, 100 ns)
  • Z80 CPU: Zilog Z0840004PSC
  • Z80 memory: NEC D4168C-20 (8Kx8 XRAM, 200 ns)
  • I/O chips: Sega 315-5308, Sega 315-5309, Sega 315-5339 (DIP-16)
  • VDP: Sega 315-5313 (Yamaha YM7101)
  • Video RAM: 2x HM53461ZP-12 (64Kx4 VRAM 120 ns)
  • Headphone amp: Sony CXA1034
  • Video encoder: Sony CXA1145
  • FM synthesizer: Yamaha YM2612
  • Capacitors : TK Japan
MD1 IC BD M5 USA VA2.jpg VA2 (USA, High Definition Graphics)
Components:
  • M68K CPU: Signetics SCN68000C8N64
  • M68K memory: 2x TC51832SPL-12 (32Kx8 PSRAM, 120 ns)
  • Z80 CPU: Zilog Z0840004PSC
  • Z80 memory: NEC D4168C-15 (8Kx8 XRAM, 150 ns)
  • I/O chips: Sega 315-5308, Sega 315-5309, Sega 315-5345 (DIP-16)
  • VDP: Sega 315-5313 (Yamaha YM7101)
  • Video RAM: 2x [NUMBER PLEASE] (64Kx4 VRAM)
  • Headphone amp: Sony CXA1034
  • Video encoder: Sony CXA1145
  • FM synthesizer: Yamaha YM2612
Genesis 1 VA 3 Serial No - 31X21232.jpg VA3 (USA, High Definition Graphics)
Components:
  • M68K CPU: Motorola MK68000P8
  • M68K memory: 2x HM65256BL-10 (32Kx8 PSRAM, 100 ns)
  • Z80 CPU: Zilog Z0840004PSC
  • Z80 memory: KM6264BL-10 (8Kx8 SRAM, 100 ns)
  • I/O chips: Sega 315-5308, Sega 315-5309
  • VDP: Sega 315-5313 (Yamaha YM7101)
  • Video RAM: KM424C64Z-10, VKF015 (64Kx4 VRAM)
  • Headphone amp: Sony CXA1034
  • Video encoder: Sony CXA1145
  • FM synthesizer: Yamaha YM2612
  • Capacitors : Taicon, Chhsi
SegaMegadriveVA4Board.jpg VA4 (JPN)
Components:
  • M68K CPU: Signetics SCN68000C8N64
  • M68K memory: 2x TC51832SP-12
  • Z80 CPU: Zilog Z0840004PSC
  • Z80 memory: NEC D4168C-15-SG
  • I/O chips: Sega 315-5364, Sega 315-5309
  • VDP: Sega 315-5313 (Yamaha YM7101)
  • Headphone amp: Sony CXA1034P
  • Video encoder: Sony CXA1145P
  • FM synthesizer: Yamaha YM2612
IC BD M5 PAL VA4.jpg VA4 (PAL)
Components:
  • M68K CPU: Motorola MC68000P8
  • M68K memory: Hitachi HM65256BLSP-10 (32Kx8 PSRAM, 100 ns)
  • I/O chip: Sega 315-5364, Sega 315-5309
  • Z80 CPU: Zilog Z0840004PSC
  • Z80 memory: Sanyo LC3664RL (8Kx8 SRAM, 120 ns)
  • VDP: Sega 315-5313 (Yamaha YM7101)
  • Video RAM: Fujitsu MB81461-12 (64Kx4 VRAM)
  • Headphone amp: Sony CXA1034P
  • Video encoder: Sony CXA1145P RGB Encoder
  • FM synthesizer: Yamaha YM2612
  • Dual Operational Amplifier: Ti LM358P
Mega Drive PCB IC BD M5 VA5.jpg VA5 (JPN)
Mega Drive PCB IC BD M5 VA6.jpg VA6 (JPN)
MD1 IC BD M5 USA VA6.jpg VA6 (USA, High Definition Graphics)
Components:
  • M68K CPU: Motorola MC68000P8
  • M68K memory: 2x HM652568LSP-10 (32Kx8 PSRAM, 100 ns)
  • Z80 CPU: Zilog Z0840004PSC
  • Z80 memory: MB8464A-10 (8Kx8 SRAM, 100 ns)
  • I/O chip: Sega 315-5433
  • VDP: Sega 315-5313 (Yamaha YM7101)
  • Video RAM: 2x [NUMBER PLEASE] (64Kx4 DRAM)
  • Headphone amp: Sony CXA1034
  • Video encoder: Sony CXA1145P
  • FM synthesizer: Yamaha YM2612
MD1 IC BD M5 PAL VA6.jpg VA6 (PAL)
VA6.8
PC BD M5 USA VA7.jpg VA7 (USA)

Model 2

MD2 JAPAN PCB VA0 UP.jpg VA0 (JPN)
PC BD MD2 VA0 PAL.jpg VA0 (PAL)
PC BD MD2 VA0 USA.jpg VA0 (USA)
Components:
  • M68K CPU: Hitachi HD68HC000CP8
  • M68K memory: Toshiba TC51832AFL-10
  • Z80 CPU: Toshiba 84C00AU-6
  • Main ASIC: Sega 315-5487-01
  • Video Encoder: Samsung KA2195D
  • Amplifier: Texas Instruments 311223J
MD2 US PCB Top VA1.jpg VA1 (USA)
PC BD MD2 VA1 PAL.jpg VA1 (PAL)
Components:
  • M68K CPU: Motorola MC68HC000FN8
  • M68K memory: Sanyo LC331632M-12
  • Z80 CPU: Toshiba 84C00AU-6
  • Main ASIC: Sega 315-5660
  • Video Encoder: Fujitsu MB3514
  • Amplifier: BA10324AF
PC BD MD2 VA1.8 USA.JPG VA1.8 (USA)
Components:
  • M68K CPU: Motorola MC68HC000FN8
  • M68K memory: Sanyo LC331632M-12
  • Z80 CPU: Zilog Z84C0006FEC
  • Main ASIC: Sega 315-5660
  • Video Encoder: Samsung KA2195D
  • Amplifier: BA10324AF
PC BD MD2 VA1.8 PAL.jpg VA1.8 (PAL)
Components:
  • M68K CPU: Motorola MC68HC000FN8
  • M68K memory: ??? 651632DFP-15
  • Z80 CPU: Zilog Z84C0006FEC
  • Main ASIC: Sega 315-5660
  • Video Encoder: Fujitsu MB3514
  • Amplifier: BA10324AF
PC BD MD2 VA1.8 ASIA.jpg VA1.8 (Asia)
Components:
  • M68K CPU: Motorola MC68HC000FN8
  • M68K memory: Toshiba TC511632FL-10 (32Kx16 PSRAM, 100 ns)
  • Z80 CPU: Toshiba 84C00AU-6
  • Z80 memory: [NUMBER PLEASE] (8Kx8 SRAM)
  • Main ASIC: Sega 315-5660
PC BD MD2 VA2 USA.jpg VA2 (USA)
PC BD MD2 VA2.3 USA.jpg VA2.3 (USA)
PC BD MD2 VA3 USA HAL.JPG VA3
PC BD MD2 VA4 171 - 7229B - 11.JPG VA4
Components:
  • IC1: Sega 315-5960 ASIC
  • IC2: 32Kx16 PSRAM
  • IC3: Video RAM?
  • IC4: Sega 315-5684 audio amplifier
  • IC5: Sony CXA1645M video encoder
  • IC6: 7805 voltage regulator

This is the first Mega Drive board without any discrete CPUs. Both the 68000 and Z80 are contained with the Sega 315-5960 ASIC, as well as the VDP, YM2612, and I/O controllers.

Model 3

PC BD MD3 VA1 USA.jpg VA1 (USA)
PC BD MD3 VA2 USA.jpg VA2 (USA)
Components:
  • Main ASIC: Sega 315-6123 (contains M68K, Z80, VDP, YM2612, and probably some other components.)
  • Memory (right of main ASIC): NEC D4502161G5 (128Kx16 SDRAM)
  • Oscillator (bottom-right of main ASIC): SG53 PTR S 53.6931M
  • Video Encoder (bottom-left of main ASIC): Sony CXA1645M
  • Amplifier (left of main ASIC): TI 85AFTRF LM324