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Namco System 12

The System 11 evolution (1997), still PlayStation-based but more powerful — the base for Tekken 3, Soul Calibur and Mr. Driller. An interchangeable COH board (PS1) + a per-game ROM board, locked by a KEYCUS (CPLD).

Identification

Field Value
Manufacturer Namco
Year 1997 (Tekken 3)
Base Sony PlayStation (PS1, revised)
Structure COH board (PS1) + game-specific ROM board
Security KEYCUS (CPLD KCxxx / MACH211) per game

Architecture (≈ PS1)

Block Chip Role
CPU MIPS R3000A (PS1) game logic
GPU custom Sony (PS1) 2D/3D rendering (more RAM than System 11)
Sound Namco C352 32 PCM voices
Media COH board + ROM board + KEYCUS program flash (2E/2J per revision)

The System 12 has more memory and an interchangeable COH board (PS1 base), hence a more ambitious catalogue than the System 11. Emulated in MAME (namco/namcos12.cpp).

Security (KEYCUS)

Like the System 11, each game has a KEYCUS — here a CPLD (KCxxx, MACH211 type) — plus a program flash (2E/2J). A conversion means handling the target game's KEYCUS, which is very hard (CPLD patch). → System 11/12 per-game KEYCUS · Namco converts guide.

Notable games

Tekken 3 (1997), Soul Calibur (1998), Tekken Tag Tournament (1999), Ehrgeiz, Point Blank 2/3, Mr. Driller (1999), Libero Grande, Paca Paca Passion, Um Jammer Lammy NOW!…

Common faults

Symptom Likely cause Lead
Won't boot KEYCUS (CPLD) / flash / ROM board Check KEYCUS; see converts
Corrupt graphics video RAM / ROM board RAM test, contacts
No/partial sound C352 Sound-stage diagnosis
Lost settings RTC/config battery Replace
No image Power, COH board, contacts 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). A leaking battery corrodes traces — check and replace it before it leaks → save batteries.
  • Flash storage 🟡: data in flash/SIMM — reprogrammable, but a failed block is permanently lost: image it before working on it → PCB preservation hub.
  • Scan rate 📺: PlayStation-based (Sony GPU) → standard ~15 kHz output, a 15 kHz chassis is fine. (Derived from the platform documented above — the screen configuration lives in the GPU device rather than the driver, so it is not measured here.)
  • FPGA / emulation: see the Emulation & FPGA section below.

Repair (technician)

  • KEYCUS (CPLD KCxxx / MACH211 per game): required to boot — check first.
  • PS1 base (COH board): PS1-type faults (recap, GPU/RAM); program in flash.
  • Sound: C352 — diagnose the sound stage.
  • Capacitors: recap. ROM board / contacts: clean.

→ Methods: PCB fault-finding · Recap · EPROM · Traces & vias

DIP settings ✅

1 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 namcos12
Setting Position Options (default in bold)
Service Mode DIP SW2:1 Off · On
Freeze DIP SW2:2 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

Emulation & FPGA

  • Emulation: MAME (namco/namcos12.cpp).
  • FPGA / MiSTer: no core (a full PS1 base).

Lineage

After the System 11 (1994), before the System 10 (NAND, 2000) and the System 246/256 (PS2).

Photos / assets

(To add: COH board, ROM board, KEYCUS CPLD, program flash.)

Sources & attribution

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.