Namco System 2¶
Namco arcade platform (1987): dual 68000 + an I/O/protection MCU, C140 sound (24 PCM voices) and zooming sprites. A very prolific late-80s 2D/pseudo-3D base — Assault, Marvel Land, Dragon Saber, Final Lap…
PCB Namco System 2 — photo by Baz1521, CC BY-SA 3.0 (Wikimedia Commons).
Identification¶
| Field | Value |
|---|---|
| Manufacturer | Namco |
| Year | 1987 |
| Connector type | Namco / JAMMA |
| Settings/save | EEPROM + battery per game |
Architecture¶
| Block | Chip | Clock | Role |
|---|---|---|---|
| Master CPU | Motorola 68000 | ~12.3 MHz | game logic |
| Slave CPU | Motorola 68000 | ~12.3 MHz | graphics/objects (offloads the master) |
| I/O MCU | Hitachi HD63705 (Namco custom) | inputs, EEPROM, protection (talks to the program) | |
| Sound CPU | Motorola 6809 | drives the sound | |
| Sound | Yamaha YM2151 (FM) + Namco C140 | C140 = 24 PCM voices (samples) | |
| Video | Namco customs (tilemaps + C116 palette) | multiple planes + zooming sprites; dedicated "road" hardware for racing games |
The dual-68000 architecture typical of Namco: one CPU runs the game, the other offloads object rendering. The racing games (Final Lap) add a "road" stage that draws the road in pseudo-3D. The Namco customs (C140, C116…) are rare — hence the importance of caring for them.
Final Lap: the multi-cabinet link
Final Lap (1987) is a landmark: up to 8 linked cabinets networked for a multiplayer race. The series (Final Lap 1/2/3) makes full use of the "road" stage.
Notable games¶
Assault, Ordyne, Marvel Land, Metal Hawk, Mirai Ninja, Phelios, Rolling Thunder 2, Steel Gunner 1/2, Valkyrie no Densetsu, Dragon Saber, Cosmo Gang, Finest Hour, Suzuka 8 Hours 1/2, Lucky & Wild, Final Lap 1/2/3…
Security & preservation¶
- Protection: the MCU (HD63705) runs protection routines on several games → without the right MCU (or its dump), the game crashes. The MCUs have been dumped by the community (MAME emulates them).
- Settings: in EEPROM (+ battery per game) — no program "suicide".
- Emulation: MAME emulates the System 2 (reverse-engineered customs and MCU). No FPGA/MiSTer core to date (Namco customs + dual 68000 + MCU).
- Rare customs (C140, C116…) → mind the contacts, the power; targeted recap.
EPROM repair: 68000 master program in 27C512/27C010 → game-by-game EPROM table.
→ Namco converts guide (MCU, System 11/12 KEYCUS…)
Common faults¶
| Symptom | Likely cause | Lead |
|---|---|---|
| Crashes at boot | protection MCU (HD63705) / sound dump | Check the MCU; MAME emulates them (community dumps) |
| No / partial sound | C140 (PCM) or YM2151 (FM) / sound 6809 | Sound-stage diagnosis |
| Corrupt sprites/planes | video customs (C116 palette…), RAM | RAM test, contacts; customs are rare |
| Lost settings / scores | EEPROM + battery per game | Replace the battery; no program "suicide" |
| No image | Power, dual 68000, harness | Base 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.
- Battery 🟢: a save battery is fitted (settings/counters/RTC). ⚠️ On this platform, a dead battery does NOT kill the game — it is a leaking battery that corrodes traces. Check and replace it before it leaks → save batteries.
- 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 📺: ~16.0 kHz / 60.6 Hz — standard resolution, a classic 15 kHz chassis is fine — the most common JAMMA case → tri-sync and upscalers.
(Computed from the MAME sources —
namco/namcos2.cpp— pixel clock ÷ htotal.) - FPGA / emulation: see the Emulation & FPGA section below.
Repair (technician)¶
- HD63705 MCU: I/O + EEPROM + protection (talks to the program); a board that refuses to boot may be the MCU/EEPROM, not the logic (donor / MAME).
- Dual 68000 (master/slave) + 6809 sound: a freeze = one of the CPUs / its RAM → separate diagnosis.
- Sound: YM2151 + Namco C140 (24-voice PCM) — diagnose the sound stage; C116 = palette (video).
- Capacitors: recap sound + filtering. Oxidised EPROM sockets: turned-pin socket.
→ Methods: PCB fault-finding · Recap · EPROM · Traces & vias
Expected clocks — measurement table ✅¶
Values extracted from the MAME sources for this platform. On a scope or frequency counter, a clock that is missing or off-value points straight at the crystal, the divider or the chip at fault — the fastest starting point on a dead board.
| Component | Expected clock | Role |
|---|---|---|
| M68000 | 12.288 MHz | main CPU |
| YM2151 | 3.579545 MHz | FM (sound) |
How to read this table
Several values for one component = several board variants in this family (or several instances of the chip clocked differently). These frequencies are those of the clock signal at the component's input, not of its original crystal — on many boards the clock is divided down from a single master crystal.
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.
- Cosmo Gang — original manual (PDF)
- Final Lap — original manual (PDF)
- Final Lap — original manual (PDF)
- Final Lap — original manual (PDF)
- Final Lap — original manual (PDF)
- Final Lap — original manual (PDF)
- Rolling Thunder 2 — original manual (PDF)
→ Full catalogue: service manuals, wiring & game manuals
DIP settings ✅¶
6 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 finalap3
| Setting | Position | Options (default in bold) |
|---|---|---|
| PortB 0x01 | — | H · L |
| Car Type(A) | — | McLaren/Williams · Lotus/March |
| PortH 0x01 | — | H · L |
| Automatic Car Select | — | No · Yes |
| PortH 0x04 | — | H · L |
| Enable Onscreen Diagnostics | — | No · Yes |
| PortH 0x10 | — | H · L |
| PortH 0x40 | — | H · L |
| Car Type(B) | — | McLaren/March · Williams/Lotus |
DIP settings — MAME set finallap
| Setting | Position | Options (default in bold) |
|---|---|---|
| PortB 0x01 | — | H · L |
| Car Type(A) | — | McLaren/Williams · Lotus/March |
| PortH 0x01 | — | H · L |
| Automatic Car Select | — | No · Yes |
| PortH 0x04 | — | H · L |
| Enable Onscreen Diagnostics | — | No · Yes |
| PortH 0x10 | — | H · L |
| PortH 0x40 | — | H · L |
| Car Type(B) | — | McLaren/March · Williams/Lotus |
DIP settings — MAME set fourtrax
| Setting | Position | Options (default in bold) |
|---|---|---|
| PortB 0x01 | — | H · L |
| PortB 0x02 | — | H · L |
| PortB 0x04 | — | H · L |
| PortB 0x08 | — | H · L |
| PortB 0x10 | — | H · L |
| PortB 0x20 | — | H · L |
| PortC 0x01 | — | H · L |
| PortC 0x02 | — | H · L |
| PortC 0x04 | — | H · L |
| PortC 0x08 | — | H · L |
| PortH 0x01 | — | H · L |
| PortH 0x02 | — | H · L |
| PortH 0x04 | — | H · L |
| PortH 0x08 (onscreen diagnostics) | — | H · L |
| PortH 0x10 | — | H · L |
| PortH 0x40 | — | H · L |
| PortH 0x80 | — | H · L |
DIP settings — MAME set kyukaidk
| Setting | Position | Options (default in bold) |
|---|---|---|
| $2000-5 | — | H · L |
DIP settings — MAME set luckywld
| Setting | Position | Options (default in bold) |
|---|---|---|
| Show Winners Don't Use Drugs | — | No · Yes |
DIP settings — MAME set suzuka
| Setting | Position | Options (default in bold) |
|---|---|---|
| Video Display | — | Normal · Frozen |
| $2000-1 | — | H · L |
| $2000-2 | — | H · L |
| $2000-3 | — | H · L |
| $2000-4 | — | H · L |
| $2000-5 | — | H · L |
| System is Status Monitor | — | No · Yes |
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
Lineage¶
Namco followed with the System 21 ("Winning Run", polygonal 3D, 1988) and the System FL, before the textured 3D of the System 246/256 (PS2 base).
Photos / assets¶
(To add: System 2 board, MCU, C140, road stage.)
Sources & attribution¶
-
Photo PCB Namco System 2 — Baz1521, CC BY-SA 3.0, Wikimedia Commons — https://commons.wikimedia.org/wiki/File:System_ii_main_01.jpg
-
Wikipedia — Namco System 2 (2× 68000, HD63705 MCU, C140 24-ch PCM, road hw, games, Final Lap link) — CC-BY-SA — https://en.wikipedia.org/wiki/Namco_System_2
- MAME — Namco System 2 driver (dumped MCUs, protection) — https://github.com/mamedev/mame
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.