Namco System 23 (Gorgon / Super System 23)¶
Namco's last in-house-designed arcade hardware (1997): an evolved textured 3D with a MIPS R4650 CPU, in Gorgon (22.5), System 23 and Super System 23 variants. Time Crisis 2, Final Furlong, 500 GP… After it, Namco moved to the PS1 (System 10/11/12).
Identification¶
| Field | Value |
|---|---|
| Manufacturer | Namco |
| Years | announced 1996, released 1997 |
| Type | textured 3D (multi-board crate), Namco's last custom design |
| Variants | Gorgon / System 22.5 · System 23 · Super System 23 (+ Evolution 2) |
| Cabinets | often cockpit / motion / gun |
Architecture¶
| Block | Chip | Role |
|---|---|---|
| CPU (Gorgon) | NKK NR4650 @ 133 MHz (MIPS) | game |
| CPU (System 23) | IDT R4650 @ 133 MHz (64-bit MIPS) | game |
| CPU (Super 23) | R4650 @ 166 MHz (Evolution 2: 200 MHz) | game |
| Sound CPU | Hitachi H8/3002 @ 16.93 MHz | drives the sound |
| Sound | Namco C352 | 32 PCM voices (like System 22) |
| I/O | Hitachi H8/3334 (Gorgon/23) → PIC16Cxx (Super 23) | controls |
| GPU | custom Namco (texture mapping) | evolution of the System 22 |
Gorgon (aka "System 22.5") is the bridge between 22 and 23 (Final Furlong, Rapid
River). The System 23 then Super System 23 raise the CPU clock and effects.
Emulated in MAME (namco/namcos23.cpp).
Notable games¶
- Gorgon (22.5): Final Furlong (1997), Rapid River.
- System 23: Time Crisis 2 (1997), Downhill Bikers, Motocross Go!.
- Super System 23: GP500, 500 GP, Crisis Zone, Guitar Jam, Angler King.
Common faults¶
| Symptom | Likely cause | Lead |
|---|---|---|
| No 3D / corrupt textures | custom GPU / texture RAM | Board-by-board crate diagnosis |
| Random freeze | R4650 / shared RAM | CPU diagnosis, RAM test |
| No/partial sound | C352 / sound H8 | Sound-stage diagnosis |
| Controls / gun dead | I/O H8/PIC / harness | I/O diagnosis |
| Cabinet motion dead | motion board / actuators | Mechanical diagnosis |
A multi-board crate + rare customs → methodical diagnosis.
Modernisation & mods¶
The common ground for every JAMMA board
Video, power, control panel and upscalers depend on the cabinet rather than the board: everything is centralised in Modernising a cabinet. To run the board outside a cabinet (at home, on a display): supergun.
- Storage 🟡: the game lives in EPROM/mask ROM on the board. Changing or restoring a game means reprogramming the EPROMs (and, for a mask ROM, using a pinout adapter) → EPROM method.
- Media preservation: replacing the original storage, multicarts, ODEs and modern options by family → PCB preservation hub.
- Scan rate 📺: ~31.45 kHz / 59.9 Hz — high resolution (VGA class), ⚠️ a 31 kHz / tri-sync monitor is required; a 15 kHz chassis is incompatible → tri-sync and upscalers.
(Computed from the MAME sources —
namco/namcos23.cpp— pixel clock ÷ htotal.) - FPGA / emulation: see the Emulation & FPGA section below.
Repair (technician)¶
- Namco's last custom design (multi-board crate, R4650 MIPS): diagnose board by board; 3D customs are rare (donor), a hard platform to source.
- H8/3002 sound CPU: silent sound = H8 / sound ROM / DAC.
- Capacitors: recap (likely SMD electrolytics). Inter-board contacts: care.
→ Methods: PCB fault-finding · Recap · Traces & vias
Original manuals for games on this platform ✅¶
Manufacturer manuals for games running on this board. Beyond the instructions, they very often carry the full DIP settings, the connector pinout, the test procedure, the parts list and the expected voltages.
- Rapid River — original manual (PDF)
→ Full catalogue: service manuals, wiring & game manuals
DIP settings ✅¶
5 games on this platform, settings extracted from the MAME sources (INPUT_PORTS_START blocks). The Position column gives the switch's physical reference on the board (SW2:!3,!4 = bank SW2, levers 3 and 4) — which is what lets you set it up without the paper manual. Games are sorted by MAME set name.
DIP settings — MAME set gmen
| Setting | Position | Options (default in bold) |
|---|---|---|
| SH-2 DIP Bit 0 | — | Off · On |
| SH-2 DIP Bit 1 | — | Off · On |
| SH-2 DIP Bit 2 | — | Off · On |
| SH-2 DIP Bit 3 | — | Off · On |
| SH-2 DIP Bit 4 | — | Off · On |
| SH-2 DIP Bit 5 | — | Off · On |
| SH-2 DIP Bit 6 | — | Off · On |
| SH-2 DIP Bit 7 | — | Off · On |
DIP settings — MAME set gorgon
| Setting | Position | Options (default in bold) |
|---|---|---|
| Service Mode DIP | DIP:1 | Off · On |
DIP settings — MAME set raceon
| Setting | Position | Options (default in bold) |
|---|---|---|
| Activate Wheel Test | DIP:4 | On · Off |
DIP settings — MAME set rapidrvrp
| Setting | Position | Options (default in bold) |
|---|---|---|
| Debug Messages | DIP:5 | Off · On |
| Dev Service Mode | DIP:2 | Off · On |
| User Service Mode | DIP:1 | Off · On |
DIP settings — MAME set s23
| Setting | Position | Options (default in bold) |
|---|---|---|
| Service Mode DIP | DIP:8 | Off · On |
| Skip POST | DIP:7 | Off · On |
| Freeze? | DIP:6 | Off · On |
Check against your own board
These settings apply to the game and revision described by MAME. One title may have several DIP sets depending on region or revision, and some systems use soft-dips (settings in memory, via the test menu) rather than physical switches. In case of a discrepancy, the board's silkscreen and the test menu are authoritative.
See also: DIP reference · game manuals
Procedure — a dead board, step by step ✅¶
What this adds
The general method lives in PCB diagnosis. This is its application to this platform: the same order, but with the values actually expected here, so you do not have to go back and forth.
Tools: multimeter, oscilloscope (or frequency counter), current-limited bench supply, desoldering braid. → Tooling
If the board is still in a cabinet
A CRT holds its charge with the machine unplugged. → CRT safety
1. Inspection, power off. Corrosion, cut tracks, oxidised EPROM legs, leaking SMD capacitors, dubious earlier repairs.
2. The connector, before anything else. A large share of "dead boards" are a contact problem, not a fault. Clean the contacts with isopropyl alcohol and reseat — not with an abrasive eraser on a gold edge, which takes the plating off and brings the problem back worse. It costs two minutes and settles the question.
3. Power, measured on the board. Aim for +5.0 V measured as close as possible to where power reaches the board — not at the PSU output: the drop is in the loom, and that is exactly what makes a board boot on the bench and not in the cabinet. Where you probe depends on this board's connector — JAMMA edge, JVS loom or a proprietary harness — plenty of makers kept one long after JAMMA arrived — see Identification above. → Wiring Check −5 V and +12 V too if the sound stage uses them. Suspected short: bring it up current-limited and find the hot spot.
4. /RESET. It must release after power-up. Held low = the CPU never starts. A 1–2 Hz loop is not the reset circuit, it is the watchdog: the CPU is crashing at boot, so look at the bus, not at the reset.
5. Clocks. There is no measurement table for this platform — MAME's sources yield nothing usable for it. Any frequency quoted under Architecture on this page serves as a marker; otherwise compare against a working board rather than against a number: an invented value condemns healthy parts. → PCB diagnosis
6. Bus. Activity on the main CPU's address lines tells you whether it is running or frozen. Frozen with good clocks and good reset → work RAM, bus buffers, ROMs.
7. It boots but the picture or the sound is wrong — that is another job: see Common faults on this page, then signal tracing.
Emulation & FPGA¶
- Emulation: MAME (
namco/namcos23.cpp). - FPGA / MiSTer: no core (multi-board textured 3D, out of budget).
Lineage¶
After the System 22 (1993). Namco's last custom design: the firm then adopted the PlayStation (System 10/11/12, to document) and later the System 246/256 (PS2).
Photos / assets¶
(To add: System 23 crate, R4650, C352, I/O board.)
Sources & attribution¶
- MAME —
namco/namcos23.cpp(R4650 MIPS, H8/3002, C352, Gorgon/23/Super 23, games) — https://github.com/mamedev/mame/blob/master/src/mame/namco/namcos23.cpp - Arcade Otaku / Wikipedia — Namco System 23 (variants, R4650 CPU, games) — https://en.wikipedia.org/wiki/Namco_System_23
Review & corrections
How this space is used
Spotted a wrong value, an outdated procedure, a chip reference that does not match your board? Say so here, with what you observed (model, board revision, serial number, measurement). Every report is cross-checked against a source before anything changes — an unverifiable correction is published as “reported by …, not cross-checked” rather than silently applied.
Reading is open to everyone; posting requires signing in with Discord. Reports from the wiki's declared reviewers are handled first; anyone else's are read too, but go through a human before anything is changed.