Sega Saturn (Model 1)
The Sega Saturn is Sega's CD-based successor to the Mega Drive, released in Japan in November 1994 and in the West the following summer. "Model 1" on this wiki means the first case design — the HST-3200, later revised as the HST-3210, with blue oval buttons and both Power and Access indicators, sold until the white HST-3220 arrived in March 1996.[1]
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| Sega's circuit board diagram for the VA0 PAL main board | |
| Specifications | |
|---|---|
| Manufacturer | Sega Enterprises, Ltd. |
| Type | Home video game console |
| Released | 22 November 1994 (Japan) 11 May 1995 (North America) 8 July 1995 (Europe)[1] |
| Discontinued | 1998 (Europe and North America)[1] |
| Intro price | ¥44,800 (Japan) • US$399.99 • £399.99[1] |
| CPU | Two 32-bit RISC SH2, 28.4 MHz, 25 MIPS each; 68EC000 at 11.3 MHz for sound[2] |
| Memory | Work RAM 16 Mbit • video RAM 12 Mbit • sound RAM 4 Mbit • CD buffer 4 Mbit • IPL ROM 4 Mbit • backup RAM 256 kbit[2] |
| Storage | Intelligent double-speed CD-ROM drive; backup RAM, expandable by cartridge[2] |
| Display | 320 × 224 dot and other modes; 1024/2048 colours from 16,770,000[2] |
| Sound | 32 channels, PCM and FM, 16-bit sampling at up to 44.1 kHz, audio DSP[2] |
| Dimensions | 260 × 230 × 83 mm[2] |
| OS / Firmware | IPL ROM, 4 Mbit (EPR-17933 / MPR-17933 on PAL machines)[2] |
| Predecessor | Sega Mega Drive / Genesis (Model 2) |
| Successor | Sega Saturn (Model 2) |
| Model no. | MK-80200-50 (PAL) • MK-80001 (North America) • MK-80208-05 (UK) • HST-3200 / HST-3210 (Japan)[2][1] |
The Saturn is mains-powered. The PAL machine is model MK-80200-50, rated AC 220–240 V at 50/60 Hz, drawing approximately 20 W, and it takes a detachable mains lead — Sega's accessories list gives three, for the UK, for SOE territories and for Australia.[2] There is no DC adaptor, no barrel jack and no external power brick. Any guide that tells you to check for 9 or 10 V at a power input is not describing this console.
Specification
editSega's own ratings and specification tables.[2]
| Item | Figure |
|---|---|
| Model (PAL) | MK-80200-50 |
| Power supply | AC 220–240 V, 50/60 Hz |
| Power consumption | Approximately 20 W |
| Operating environment | 5 to 35 °C, 10% to 80% RH, non-condensing |
| Dimensions | 260 (W) × 230 (L) × 83 (H) mm |
| CPU, master and slave | 32-bit RISC SH2, 28.4 MHz, 25 MIPS each |
| CPU, sound | 68EC000, 11.3 MHz |
| Work RAM | 16 Mbit |
| Video RAM | 12 Mbit |
| Sound RAM | 4 Mbit |
| CD buffer RAM | 4 Mbit |
| IPL ROM | 4 Mbit |
| Backup RAM | 256 kbit |
| Resolution | 320 × 224 dot and others |
| Colours | 1024/2048, from 16,770,000 |
| Scroll screens | Five maximum; four XY scroll, two rotation, two enlargement/reduction, two windows, vertical cell scroll and lateral line scroll |
| 3D | Dedicated polygon hardware, wire frame, flat shading, Gouraud shading |
| Sound | 32 channels, PCM and FM, 16-bit sampling, 44.1 kHz maximum, audio DSP |
| Optical drive | Intelligent double-speed CD drive |
The service manual's block diagram gives a master clock of 28.6 MHz and a 14.318 MHz reference into the PLL, against the 28.4 MHz quoted in the specification table; the two figures are for the same part and the difference is a rounding convention rather than two different machines.[2][3]
Rails
editFrom Sega's block diagram, measured at the main board's power connector.[2]
| Rail | Feeds |
|---|---|
| +9 V | CD drive, and the PLL |
| +5 V | All chips other than the SDRAM |
| +3.3 V | SDRAM |
There is no +12 V rail on a Saturn, and no negative rail. The supply is a bought-in switching module mounted inside the case, and its manufacturer varies by machine and market.[2][4]
On VA0 PAL boards the position silkscreened FUSE is filled with a jumper wire, Sega part 600-6458, "JUMPER WIRE L=10MM".[2] There is nothing to test there.
Boards
editSega's manual identifies the boards as the main board, the CD drive unit, the power board, the power indicator board, the P.SW board and the R.SW board, with the SH-1 board above the main board.[2]
The bare PAL main board numbers for the earliest machines are 837-11491 and 837-11493.[4]
IC map, VA0 main board
editFrom Sega's electrical parts list.[2]
| Designator | Device | Function |
|---|---|---|
| IC1, IC2 | HD6417095F28 | The two SH-2 CPUs |
| IC3, IC4, IC11 | 4 Mbit SDRAM | Work RAM |
| IC5 | 315-5688 | SCU, system control unit |
| IC6 | 315-5778 | DCC |
| IC7 | EPR-17933 / MPR-17933 | IPL ROM — the PAL part; NTSC machines carry a different ROM |
| IC9 | 315-5744 | SMPC, system manager and peripheral controller. The controller ports run through it |
| IC10 | 315-5689 / 315-5883 | VDP1 — sprites and polygons |
| IC12, IC13, IC15, IC16 | 2 Mbit SDRAM | Video RAM |
| IC14 | 315-5690 / 315-5890 | VDP2 — backgrounds and scrolling |
| IC17 | 315-5687 | SCSP, sound processor |
| IC18 | MC68EC000FN12 | Sound CPU |
| IC19 | 4 Mbit DRAM | Sound RAM |
| IC20 | 315-5746 | PLL, fed from the 14.318 MHz reference |
| IC21 | CXA1645M | RGB encoder — this, not a VDP, drives the AV connector |
| IC22 | TDA1386T or PCM1717E | Audio DAC[4] |
| IC25 | S-80741AL | Voltage detector |
| IC31, IC32 | 4 Mbit DRAM | CD buffer RAM |
Connections
editSega's identifying-parts drawing gives the console's external connections as the power jack (the mains inlet for the detachable lead), the AV OUT jack, two control ports, the cartridge slot, the OPEN button, the ACCESS light and the Master Reset switch.[2]
There is no S-video output and no dedicated composite socket: everything leaves on the single multi-AV connector, and what you get depends on the lead. PAL machines shipped with an RGB cable.[2]
Backup battery
editSaves and the clock are held up by a CR2032 cell; Sega's accessories list gives it as "Lithium Battery (CR2032)" with the note "Positive Side B".[2] A machine that forgets its saves and its clock wants a cell, not a board repair.
CD drive
editSeveral different CD-ROM boards were fitted across the range — JVC EXL-P604, EXL-P605 and ENR-007 B/D, Hitachi JA00292 and Sanyo CDK94V5SGC — so a drive from one Saturn is not necessarily the same assembly as the drive in another.[4]
Sega's maintenance figures, and its warning about the one adjustment people reach for first, are on Sega Saturn (Model 1) Maintenance Guide.
Documentation
edit- Sega Service Manual - Sega Saturn Pal - 1 June 1995 — No. 013-1, June 1995, the PAL service manual with the VA0 parts list.
- Sega Saturn VA13 Service Manual (PAL) — a partial scan of the later VA13 board's schematics, with no parts list.
- Sega Saturn VA0.5 Schematics.
Related pages
editReferences
edit- ↑ 1.0 1.1 1.2 1.3 1.4 Sega Saturn, Sega Retro. Secondary source. Release dates, recommended retail prices and Sega model codes, each footnoted on that page to a contemporary source: Japan 22 November 1994 at ¥44,800 (HST-0001), North America 11 May 1995 at US$399.99 (MK-80001), Western Europe 8 July 1995, United Kingdom 8 July 1995 at £399.99 (MK-80208-05), Germany, Spain and France 7 July 1995. Also the source for the two case designs — the HST-3200, later revised as the HST-3210, sold from the Japanese launch until early 1996 with blue oval buttons and both Power and Access LEDs, and the HST-3220 announced at Sega Saturn Power Up Meeting '96 Spring and released on 22 March 1996, whose only functional change is the omission of the Access LED — and for the statement that overseas machines are physically identical to the Japanese ones save for region encoding and black plastic.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 Sega Enterprises, Ltd., Service Manual — Sega Saturn (PAL), No. 013-1, June 1995 — hosted on this wiki as File:Sega service manual - sega saturn pal - no. 013-1 june 1995.pdf (see Sega Service Manual - Sega Saturn Pal - 1 June 1995). Section 1 gives the ratings and specification (model MK-80200-50, AC 220–240 V 50/60 Hz, approximately 20 W, 5–35 °C and 10–80% RH non-condensing, 260 × 230 × 83 mm, master and slave 32-bit RISC SH2 at 28.4 MHz and 25 MIPS, 68EC000 at 11.3 MHz for sound, work RAM 16 Mbit, video RAM 12 Mbit, sound RAM 4 Mbit, CD buffer RAM 4 Mbit, IPL ROM 4 Mbit, backup RAM 256 kbit, 320 × 224 dot, 1024/2048 colours from 16,770,000, five screens maximum, 32 sound channels with PCM and FM and a 16-bit 44.1 kHz maximum sampling rate, and an intelligent double-speed CD drive); section 3 the accessories (lithium battery CR2032, RGB cable, and AC cables for the UK, SOE and Australia); section 4 the board identifications; section 5 the disassembly; section 6 the CD drive maintenance and adjustment figures; section 7 the block diagram with the power supply rails; section 9 the circuit board diagrams and section 11-3 the electrical parts list for the VA0 main board.
- ↑ Sega Saturn VA13 Service Manual (PAL) — hosted on this wiki as File:Sega Saturn VA13 Service Manual PAL.pdf (see Sega Saturn VA13 Service Manual (PAL)). A partial scan, redrawn and watermarked by a third party: an overall block diagram giving the 28.6 MHz 32-bit clock and the 14.318 MHz PLL reference, eleven main-board schematic sheets and power supply and CD unit sheets. It carries no parts list. Sheet 1/11 shows IC1 and IC2 as the two Hitachi SH-2 devices (IC2 marked 315-0998) with IC3 and IC4 as 4 Mbit SDRAMs on a separate LVCC supply; sheet 2/11 shows IC5 as a Yamaha 315-5966, a different part from the VA0 board's IC5.
- ↑ 4.0 4.1 4.2 4.3 console5 TechWiki, Saturn, https://wiki.console5.com/wiki/Sega_Saturn . Secondary source — per-revision capacitor lists read off real boards, covering VA0 through VA15, the power supply units by manufacturer and model, and the CD-ROM PCBs. Its VA0 PAL list (837-11491 / 837-11493) agrees position for position with the parts list in Sega's own PAL service manual, including the values at CE30 and CE54 that are specific to PAL boards.