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(VA2 [PC BD MD2 VA2 USA])
(VA2 [PC BD MD2 VA2 USA])
Line 555: Line 555:
 
| IC3 || Rohm || BA10358 || Dual ground sense operational amplifier || -
 
| IC3 || Rohm || BA10358 || Dual ground sense operational amplifier || -
 
|-
 
|-
| IC4 || Zilog || Z84C0006FEC || Zilog Z80 8-bit coprocessor || -
+
| IC4 || Zilog, Sega|| Z84C0006FEC (Zilog), 315-5676 (Sega)|| Zilog Z80 8-bit coprocessor || -
 
|-
 
|-
| IC5 || ? || XL J6265AF-10SL || || -
+
| IC5 || Sanyo, Rohm|| LC3664BML-10 (Sanyo),
  +
XLJ6265AF-10SL (Rohm)
  +
|| 64K (8K x 8bit) CMOS SRAM|| -
 
|-
 
|-
 
| IC6 || Sega || 315-5786 (Toshiba T9N13BF) || I/O, Bus arbiter, VDP, TMSSVDP and IO chip all-in-one. Doesn't include the YM2612.
 
| IC6 || Sega || 315-5786 (Toshiba T9N13BF) || I/O, Bus arbiter, VDP, TMSSVDP and IO chip all-in-one. Doesn't include the YM2612.

Revision as of 21:00, July 26, 2020

Sega Mega Drive Motherboard revisions

Model 1

VA1 [IC BD M5 VA1]

IC BD M5 VA1
List of IC's
IC# Brand Name Description Documentation
IC1 Signetics SCN68000C8N64 8MHz Processor -
IC2/IC3 Toshiba TC51832SPL-12 CMOS 256K (32K x 8) Pseudo-SRAM, 12ns -
IC4 SEGA 315-5308 I/O chip -
IC5 SEGA 315-5309 I/O chip -
IC6 Zilog Z0840004PSC Zilog Z80 8-bit coprocessor -
IC7 NEC D4168C-15-SG 64K (8,192 x 8-BIT) NMOS XRAM -
IC8 SEGA 315-5313 (Yamaha YM7101) VDP -
IC9/IC10  ?  ? Video 256K (64K x 4) DRAM -
IC11 Yamaha YM2612 frequency modulation synthesizer -
IC12 Sony CXA1034 Headphone amp -
IC13  ?  ?  ? -
IC14  ?  ?  ? -
IC15  ?  ?  ? -
IC16 Sega 315-5339 (DIP16) I/O chip -


VA2 [IC BD M5 USA VA2] 837-6992

IC BD M5 USA VA2
List of IC's
IC# Brand Name Description Documentation
IC1 Signetics SCN68000C8N64 8MHz Processor -
IC2/IC3 Toshiba TC51832SPL-12 CMOS 256K (32K x 8-bit) Pseudo-SRAM, 12ns -
IC4 SEGA 315-5308 I/O chip -
IC5 SEGA 315-5309 I/O chip -
IC6 Zilog Z0840004PSC Zilog Z80 8-bit coprocessor -
IC7 NEC D4168C-15 64K (8K x 8) NMOS XRAM, 150 ns -
IC8 SEGA 315-5313 (Yamaha YM7101) VDP -
IC9/IC10 Samsung & NEC KM424C64Z-10 & D41264V-12 256K (64K x 4-bit) VRAM & Dual-Port Graphics Buffer -
IC11 Yamaha YM2612 frequency modulation synthesizer (Sound Chip) HERE
IC12 Sony A1034(CXA1034P/M) Headphone amp HERE
IC13 Sony CXA1145 Video encoder HERE
IC14 Hitachi HA17358 dual operational amplifier HERE
IC15/IC17  ? 7805 +5V Regulator -
IC16 Sega 315-5345 (DIP16) I/O chip -


VA3 [IC BD M5 USA VA3] 837-7071

List of IC's
IC# Brand Name Description Documentation
IC1 Signetics SCN68000C8N64 8MHz Processor -
IC2/IC3 Toshiba TC51832SPL-12 CMOS 256K (32K x 8) Pseudo-SRAM, 12ns -
IC4 SEGA 315-5364 I/O chip -
IC5 SEGA 315-5309 I/O chip -
IC6 Zilog Z0840004PSC Zilog Z80 8-bit coprocessor -
IC7 NEC D4168C-15-SG 8,192 x 8-BIT NMOS XRAM, 150 ns -
IC8 SEGA 315-5313 I/O chip -
IC9/IC10 Fujitsu MB81461-12 256K (64K x 4-bit) VRAM -
IC11 |YM2612 frequency modulation synthesizer -
IC12 Sony CXA1034 Headphone amp -
IC13 Sony CXA1145P RGB Encoder -
IC14  ? LM358N Dual Operational Amplifier -


VA4 [IC BD M5 PAL VA4]

List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68000P8 8MHz Processor -
IC2/IC3 Hitachi HM65256BLSP-10 256Kb (32Kx8) Psuedo Static RAM, 100ns -
IC4 SEGA 315-5364 I/O chip -
IC5 SEGA 315-5309 I/O chip -
IC6 Zilog Z0840004PSC Zilog Z80 8-bit coprocessor -
IC7 Sanyo LC3664RL 64Kb (8Kx8) NMOS Static RAM, 120ns -
IC8 SEGA 315-5313 I/O chip -
IC9/IC10 Fujitsu MB81461-12 256K (64K x 4-bit) VRAM -
IC11 Yamaha YM2612 frequency modulation synthesizer -
IC12 Sony CXA1034P Headphone amp -
IC13 Sony CXA1145P RGB Encoder -
IC14 Ti LM358P Dual Operational Amplifier -


VA5

The only difference is the IC4 315-5402


VA6 [IC BD M5 PAL]

Genesis pal model1 M5
List of IC's
IC# Brand Name Description Documentation
IC1 Hitachi HD68HC000P8 8MHz Processor -
IC2/IC3 Motorola MCM51L832ASP10 CMOS 1024 BIT SRAM -
IC4 SEGA 315-5433 I/O chip -
IC5 SEGA 315-5313A I/O chip -
IC6 Zilog Z0840004PSC Zilog Z80 8-bit coprocessor -
IC7 Fujitsu MB8464A-10LL-SK CMOS 65,536 SRAM -
IC8  ?  ?  ? -
IC9/IC10 Fujitsu MB81461-12SL 256k 120ns Video RAM Dual Port -
IC11 Yamaha YM2612 Audio -
IC12 SONY CXA1034P Amplifier -
IC13 SONY CXA1145P Video -
IC14  ?  ?  ? -


VA6 [IC BD M5 USA VA6]

List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68000P8 8MHz Processor -
IC2/IC3 Motorola MCM51L832ASP10 256Kb (32K x 8-bit) SRAM -
IC4 SEGA 315-5433 I/O chip -
IC5 SEGA 315-5313A I/O chip -
IC6 Zilog Z0840004PSC Zilog Z80 8-bit coprocessor -
IC7 Samsung KM6264BL-10 64Kb: (8K x 8-bit) SRAM -
IC8 SEGA 315-5313 I/O chip -
IC9/IC10 Samsung & NEC KM424C64Z-10 & D41264V-12 256K (64K x 4-bit) VRAM & dual-port graphics buffer -
IC11 Yamaha YM2612 Audio -
IC12 SONY CXA1034P Headphone Amplifier -
IC13 SONY CXA1145P RGB Video -
IC14 Hitachi HA17358 Dual operational amplifier -
IC15/17  ? 7805 +5 Voltage Regulator -


VA6.8


VA7 [PC BD M5 USA VA7] 171-6217-11

PC BD M5 USA VA7

The VA7 is almost a Genesis 2 PCB in a Genesis 1 case. It even shares the same PCB prefix (PC).

List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN8 Processor -
IC2/IC3 Hitachi HM65256BLFP-10T CMOS 256K (32K x 8) High Speed Pseudo-Static RAM HERE
IC4 Zilog Z0840004PSC Zilog Z80 8-bit coprocessor -
IC5 Fujitsu MB8464A-10L 64K (8192 words x 8 bits) Low Power SRAM -
IC6 SEGA 315-5487-01 I/O, Bus arbiter, VDP, ym2612, TMSS -
IC7/IC8 Hitachi HM53461ZP-12SG 65,536-WORDx4-bit Multiport CMOS video ram HERE
IC9/IC10 Rohm BA10324AF Op-amp HERE
IC11 SONY CXA1145M Video -
IC12 Toshiba TA7805S +5V Voltage regulator -


List of Electrolytic Capacitors
CE# Capacitance Voltage
CE1 10 μF 16 V
CE2 10 μF 16 V
CE3 10 μF 16 V
CE4 10 μF 16 V
CE5 10 μF 16 V
CE6 10 μF 16 V
CE7 10 μF 16 V
CE8 10 μF 16 V
CE9 220 μF 10 V
CE10 220 μF 10 V
CE11 10 μF 16 V
CE12 220 μF 10 V
CE13 10 μF 16 V
CE14 10 μF 16 V
CE15 10 μF 16 V
CE16 220 μF 16 V
CE17 100 μF 10 V
CE18 47 μF 10 V
CE19 47 μF 10 V
CE20 10 μF 16 V
CE21 10 μF 16 V
CE22 10 μF 16 V
CE23 100 μF 10 V
CE24 47 μF 10 V
CE25 47 μF 10 V
CE26 47 μF 10 V
CE27 47 μF 10 V
CE28 47 μF 10 V
CE29 10 μF 16 V
CE30 10 μF 16 V
CE31 100 μF 10 V
Totals
17 10 μF 16 V
7 47 μF 10 V
3 100 μF 10 V
4 220 μF 10 V

Model 2

VA0 PAL


VA1 [PC BD MD2 VA1 USA]

Model2 va1 motherboard
List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN8 Processor -
IC2 Toshiba TC511632FL-10 65,536 Word x 16 Bit Dynamic Ram -
IC3  ?  ?  ? -
IC4 SEGA 315-5678 (?) Z80 8-bit processor -
IC5 Fujitsu M88464A-10L 8K Words x 8-Bit (64K) CMOS SRAM Low Power -
IC6 SEGA 315-5487, 315-5660, 315-5660-01/02, 315-5708 I/O, Bus arbiter, VDP, modified YM3438 (YM2612 compatible) FM synthesizer, TMSS.

315-5487 may have problems running in PAL mode.

-
IC7 OKI M54C864-80 65,536-Word x 8-Bit Multiport DRAM -
IC8  ?  ?  ? -
IC9/IC10 Texas Instruments, Rohm, NEC/Renesas LM324, BA10324, C324G Low power quad op amps -
IC11 Sony, Samsung,

Fujitsu

CXA1145M, KA2195D,

MB3514

RGB Encoder (KA2195D is NTSC only) HERE
IC12  ?  ? Voltage regulator -


VA1 [PC BD MD2 VA1 PAL]

List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN8 Processor -
IC2 Toshiba TC511632FL-10 65,536 Word x 16 Bit Dynamic Ram -
IC3  ?  ?  ? -
IC4 Toshiba 84C00AU-6 Z80 clone -
IC5 Fujitsu MB8464H-10LL 8K Words x 8-Bit (64K) CMOS SRAM Low Power -
IC6 SEGA 315-5660  ? -
IC7 OKI M54C864-80 65,536-Word x 8-Bit Multiport DRAM -
IC8  ?  ?  ? -
IC9/IC10 Rohm BA10324AF Low power quad op amps -
IC11 Fujitsu MB3514 Video (RGB Encoder) -
IC12  ?  ? Voltage regulator -


VA1 [PC BD MD2 VA1 ASIA]

2016-04-08 17.54.49 cr
List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN8 Processor -
IC2 Toshiba TC511632FL-10 512K (32K x 16-bit) PSRAM, 100 ns -
IC4 Toshiba 84C00AU-6 Z80 8-bit coprocessor -
IC5 Sanyo LC3664BML-10 64K (8Kx8-bit) SRAM -
IC6 Sega 315-5660, 315-5660-01/02,

315-5708

I/O, Bus arbiter, VDP, modified YM3438 FM synthesizer, TMSS -
IC7 Hitachi HM53861J-8 512K (64K x 8-bit) VRAM -
IC9/IC10 Texas Instruments,

Rohm, NEC/Renesas

LM324, BA10324,

C324G

ground sense quad op-amp -
IC11 Fujitsu MB3514 RGB Encoder -
IC12 Voltage Regulator -

VA1.8 [PC BD MD2 VA1.8 USA]

PC BD MD2 VA1.8 USA
List of IC's
IC# Brand Name Description Documentation
IC2 Hitachi / Sanyo 651632DFP-15 / LC331632M-12 512K (32K x 16-bit) SRAM -
IC3  ?  ?  ? -
IC4 Zilog Z84C0006FEC Zilog Z80 8-bit coprocessor -
IC5 Rohm XLJ6265AF-10SL 64K (8K x 8-bit) CMOS SRAM -
IC6 SEGA 315-5660, 315-5660-01/02, 315-5708 I/O, Bus arbiter, VDP, modified YM3438 FM synthesizer, TMSS -
IC7 Samsung KM428C64J-10 512K (64K x 8-bit) VRAM -
IC8  ?  ?  ? -
IC9/IC10 Rohm BA10324AF ground sense quad op-amp -
IC11 Sony, Samsung, Fujitsu CXA1145M, KA2195D,

MB3514

RGB Encoder (KA2195D is NTSC only) HERE
IC12  ? 7805 +5V Voltage regulator -


VA1.8 [PC BD MD2 VA1.8 PAL]

Genesis pal model2 VA1.8
List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN8 Processor -
IC2  ? 651632DFP-15 512K (32K x 16-bit) SRAM -
IC3  ?  ?  ? -
IC4 Zilog Z84C0006FEC Zilog Z80 8-bit coprocessor -
IC5 Rohm BR6265BF-10SL 64K (8K x 8-bit) CMOS SRAM -
IC6 SEGA 315-5660, 315-5660-01/02,

315-5708

I/O, Bus arbiter, VDP, modified YM3438 FM synthesizer, TMSS -
IC7 Hitachi HM53861J-8 512K (64K x 8-bit) VRAM -
IC8  ?  ?  ? -
IC9/IC10 Rohm BA10324AF ground sense quad op-amp -
IC11 Fujitsu MB3514 RGB Encoder HERE
IC12  ? 7805 +5V Voltage regulator -


VA1.8 [PC BD MD2 VA1.8 ASIA]

PC BD MD2 VA1.8 ASIA
List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN8 Processor -
IC2 Toshiba TC511632FL-10 512K (32K x 16-bit) PSRAM, 100 ns
IC3  ?  ?  ? -
IC4 Toshiba 84C00AU-6 Z80 8-bit coprocessor -
IC5  ?  ? 64K (8Kx8-bit) SRAM -
IC6 Sega 315-5660 -
IC7 Hitachi HM53861J-8 512K (64K x 8-bit) VRAM -
IC8  ?  ?  ? -
IC9/IC10 Rohm BA10324AF ground sense quad op-amp -
IC11 Fujitsu MB3514 RGB Encoder -
IC12 7805 Voltage Regulator -


VA2 [PC BD MD2 VA2 USA]

This revision, along with the VA2.3, uses a discrete YM2612 FM synthesizer. It is also the first Model 2 to feature the 315-5684 sound network/headphones amplifier. A small daughterboard with a 74HC14 hex-inverting schmitt trigger is typically present, its function is unknown. The BA10358 op-amplifier serves as the FM pre-amplifier.

A series resistor at R31 is responsible for the distorted PSG sound reported on these models. Replacing R31 with a 0-ohm jumper fixes the PSG distortion.

List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN12 Processor
-
IC2 Sanyo LC331632M-12 512K (32768 words X 16 bits) Pseudo-SRAM
IC3 Rohm BA10358 Dual ground sense operational amplifier -
IC4 Zilog, Sega Z84C0006FEC (Zilog), 315-5676 (Sega) Zilog Z80 8-bit coprocessor -
IC5 Sanyo, Rohm LC3664BML-10 (Sanyo),

XLJ6265AF-10SL (Rohm)

64K (8K x 8bit) CMOS SRAM -
IC6 Sega 315-5786 (Toshiba T9N13BF) I/O, Bus arbiter, VDP, TMSSVDP and IO chip all-in-one. Doesn't include the YM2612. -
IC7 Samsung KM428C64J-10 64K x 8 Bit CMOS Video RAM
-
IC8 Yamaha YM2612 frequency modulation synthesizer -
IC9 Sega 315-5684 (Rohm BA6166FS) Sound Network/Headphone AMP -
IC11 Samsung, Sony KA2195D

(Samsung),

CXA1645M (Sony)

RGB Encoder -


VA2.3 PC BD MD2 VA2.3 USA

MD2VA2-3 452018272
This revision integrates the 74HC14 hex-inverting Schmitt trigger, and moves some components around. Most VA2.3s use the 315-5685 main ASIC, but some systems may use the 315-5786 alternatively. The 315-5685 ASIC has slightly broken shadow/highlight support, where the shadow/highlight effects are offset to the right by one pixel onscreen. The 315-5786 ASIC does not have this problem.

As with the VA2, a series resistor at R31 causes PSG distortion. Replacing it with a 0-ohm jumper fixes this distortion.

List of IC's
IC# Brand Name Description Documentation
IC1 Motorola MC68000FN12 Processor -
IC2 Toshiba TC511632FL-10 512K (32768 words X 16 bits) Pseudo-SRAM -
IC3 Rohm BA10358 Dual ground sense operational amplifier -
IC4 Zilog Z84C0006FEC Zilog Z80 8-bit coprocessor -
IC5  ? XL J6265AF-10SL 4K (8K x 8-bit) CMOS SRAM -
IC6 Sega 315-5786 (Toshiba T9N13BF)

or 315-5685

VDP and IO chip all-in-one. Doesn't include the YM2612.

315-5685 ASICs have faulty shadow/highlight support.

-
IC7 Toshiba TC5281286J-80 1M (128K x 8-bit) VRAM -
IC8 Yamaha YM2612 frequency modulation synthesizer -
IC9 SEGA 315-5684 (Rohm BA6166FS) SOUND NETWORK / HEADPHONE AMP -
IC11 Samsung, Sony KA2195D, CXA1645M RGB Encoder -
IC12  ? 7805 +5V voltage regulator -
IC13  ? 74HC14 HEX SCHMITT-TRIGGER INVERTER -


VA3 [PC BD MD2 VA3 USA HAL]

PC BD MD2 VA3 USA HAL
This is the first Model 2 system to utilize a smaller motherboard footprint. It is essentially a much improved VA1.8, using the 315-5684 amplifier first featured on the VA2 and VA2.3 revision motherboards. The PSG distortion problems have been fixed with this revision.

This is also the last motherboard revision to feature the NTSC-only Samsung KA2195D encoder. Early VA3 systems may use the older Sony CXA1145M encoder, while most use either the KA2195D or CXA1645M encoders.

List of IC's

IC# Brand Name Description Documentation
IC1 Motorola MC68HC000FN8 Processor -
IC2 Hitachi(?) 651632DFP-15 512K (32K X 16-bits) Pseudo-SRAM -
IC3  ?  ?  ? -
IC4 Zilog Z84C0006FEC Zilog Z80 8-bit coprocessor -
IC5  ?  ? 64K (8K x 8-bit) SRAM -
IC6 Sega 315-5660, 315-5660-01/02,

315-5708, 315-5700 (FF1004)

VDP and IO chip all-in-one. -
IC7 OKI M54C864-80 512K (64K x 8-bit) VRAM -
IC8  ?  ?  ? -
IC9 SEGA 315-5684 (Rohm BA6166FS) SOUND NETWORK / HEADPHONE AMP -
IC10  ?  ?  ? -
IC11 Sony, Samsung CXA1145M, CXA1645M, KA2195D RGB Encoder (KA2195D is NTSC only) -
IC12  ? 7805 +5V Voltage Regulator -


VA4 [PC BD MD2 VA4]

GEN2 VA4 MK1451
Final Model 2 motherboard revision. This system features a 'Genesis-on-a-Chip' (GOAC), which integrates the VDP, FM sound source, 68000 and Z80 CPUs into one chip. First revision Model 3 systems also use this ASIC. It also uses a similar reduced motherboard footprint to the VA3 model.

Model 3

VA1

VA2

Notes

Most of the time the main SEGA IC's are based on/renamed chips from other brands as follows:

  • MD1 VA0, VA1, VA2, VA3, VA4, VA5, VA6, VA6.8
Yamaha YM7101 / FC1001 = Sega 315-5313 / 315-5313A / 315-5313A-01
Yamaha YM6045 / YM6045C = Sega 315-5308 / 315-5364
Yamaha YM6046 = Sega 315-5309
  • MD1 VA7 & MD2 VA0, VA1, VA1.8, VA3
Yamaha FC1004 = Sega 315-5487 / 315-5487-01 / 315-5487-10 / 315-5660 / 315-5660-02 / 315-5708 / 315-5708-01
Yamaha FF1004 = Sega 315-5700
  • MD2 VA2, VA2.3
Toshiba T9N13BF = Sega 315-5786
Toshiba TC6158AF = Sega 315-5685. This ASIC has slightly broken shadow/highlight support.
Rohm BA6166 = Sega 315-5684
  • MD2 VA4 & GEN3 VA1
Yamaha FJ3002 = Sega 315-5960
  • GEN3 VA2
Yamaha FQ8007 = Sega 315-6123

See Also

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