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Capcom CP System III (CPS-3)

Capcom's last proprietary arcade platform (1996), before the move to the Naomi. Home of Street Fighter III, Red Earth/Warzard, JoJo. Architecture of CD-ROM + flash SIMMs + security cartridge — and the most feared suicide: when the cartridge battery dies, the game dies with it.

Identification

Field Value
Manufacturer Capcom
Years 1996 → 1999 (6 games)
System / family CPS-3
Media CD-ROM (SCSI) + flash SIMMs + security cartridge
Connector type JAMMA
Resolution 384×224 (or 496×224 widescreen)
Colours 32,768 on screen (16.7M palette)

The 6 games

Red Earth / Warzard (1996), Street Fighter III: New Generation (1997), SFIII 2nd Impact (1997), JoJo's Bizarre Adventure (1998), SFIII 3rd Strike (1999), JoJo's Bizarre Adventure: Heritage for the Future (1999).

Architecture

Block Component
CPU Hitachi SH-2 (HD6417099) @ 25 MHz, integrated decryption
Storage SCSI CD-ROM drive + Flash ROM SIMMs (up to 8 × 16 MB)
RAM 512 KB work, 512 KB sprite, 8 MB character, 256 KB colour…
Sound 16 stereo channels, 8-bit samples

Operation & security

  1. The (encrypted) game data is on the CD.
  2. At power-on it is loaded into the flash SIMMs.
  3. The security cartridge holds the BIOS + the decryption keys, stored in battery-backed SRAM.

The "suicide"

When the cartridge battery dies, the keys are lost → the cartridge becomes unplayable (dead board). This is the CPS-3 suicide, reputedly severe.

  • Exception: SFIII 2nd Impact used hard-coded default keys → it works again even with a dead battery.
  • Crack: Andreas Naive reverse-engineered the encryption in June 2007 → emulation + "super cartridges" that bypass the security.

Solutions (preservation)

1. Replace the battery (cartridge still alive) Solder a fresh battery without cutting power to the keys (keep the SRAM powered during the swap) — otherwise suicide. On an already-dead cartridge, the battery alone isn't enough: you must reprogram (below).

2. Phoenix / no-battery BIOS After the crack (2007), decrypted BIOS/data or default keys are available → the cartridge runs without a battery. Requires reflashing the cartridge / SIMM ROMs.

3. CD-less / SD multi (the modern solution) The Darksoft CPS-3 kit replaces CD + cartridge + battery with SD storage: all CPS-3 games, no more suicide, no more CD drive (the mechanical weak point). Today it's the most reliable preservation route.

In short: a CPS-3 is preserved durably either battery-less (phoenix), or via an SD multi. Keeping an original cartridge alive requires permanent battery vigilance.

Common faults

Symptom Likely cause Lead
Dead cartridge / won't boot Flat battery (suicide) Phoenix / no-battery, or SD multi
CD load errors Worn SCSI CD drive / damaged CD Repair/replace drive, or SD multi
Corrupted graphics Flash SIMMs / contacts Reflash SIMMs, reseat
No image Power / SH-2 / contacts Base diagnosis

Conversions & mods

  • SD multi (Darksoft): all CPS-3 games, no CD or battery.
  • ⚠️ Do not host ROMs — method only.

→ CPS-3 converts guide (CD + cartridge + SIMM) · CPS-3 Darksoft multi

Emulation & FPGA

  • MAME: emulation born of reverse-engineering (Bart Trzynadlowski, Andreas Naive) — SH-2, program encryption, CD-ROM stream, SIMMs.
  • FPGA / MiSTer: no core to date — SH-2 + CD-ROM + large SIMMs exceed the DE10-Nano's budget. Preservation = MAME + no-CD / no-battery hardware solutions (see CPS-3 converts).

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. On this platform the battery is the first suspect: its leakage eats tracks under the holder, and the damage is often hidden by the battery itself. Lift it to look.

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.

Procedure — replacing the battery without losing the key ✅

The order is the whole procedure

The decryption key of the cartridge security lives in SRAM held up by that battery. Cutting the old cell before the new one is soldered erases it, instantly and for good: the board goes silent and only a de-suicide brings the game back. So the new cell goes in first, in parallel.

  1. Board powered off, old battery left in place.
  2. Measure the old cell in circuit and note it (a CR2032 is 3 V nominal). This is what tells you whether you are ahead of the failure or already behind it.
  3. Solder the new cell in parallel with the old one — piggyback — watching polarity. A reversed cell discharges the old one through itself and erases the key just as surely.
  4. Re-measure at the holder: the voltage must have come back up. Do not go on before it has.
  5. Only now, remove the old cell.
  6. Power up and check the game boots.

→ Backup batteries

Already dead? This procedure will not bring it back — the key is gone. → de-suicide

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.

  • Anti-suicide — the priority mod 🟠: this platform suicides (key/program held by a battery). Replacing the battery without cutting power only postpones the problem; the durable route is de-suiciding → conversions and de-suiciding → save batteries.
  • Optical storage 🟡: the drive is the number-one wear part. Modern routes: an ODE, netboot, or replacement by flash storage depending on the platform → PCB preservation hub.
  • Scan rate 📺: ~15.73 kHz / 59.6 Hz — standard resolution, a classic 15 kHz chassis is fine → tri-sync and upscalers. (Computed from the MAME sources — capcom/cps3.cpp — pixel clock ÷ htotal.)
  • FPGA / emulation: see the Emulation & FPGA section below.

Repair (flash, not EPROM)

The CPS-3 stores the game on flash SIMMs (no classic program EPROM) + an encrypted cartridge/CD. ⚠ Severe suicide (battery → key lost). SIMM/de-suicide detail: CPS-3 converts.

Repair — security & battery (technician)

  • Battery-backed security cartridge: the CPS-3 decrypts via a battery-backed key (in the cartridge) → flat battery = suicide (dead game, healthy hardware). See backup batteries; remade SIMMs are possible (preservation).
  • Flash SIMMs: game data lives on Flash (no EPROM), installed from the CD — see the flash section above.
  • SCSI CD-ROM drive: mechanism/laser = a weak point → optical cleaning.
  • Capacitors: recap PSU + audio filtering.

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

Photos / assets

(To add: base board, security cartridge + battery, SIMMs, CD drive.)

Archived original documents ✅

Manufacturer documents archived locally, found in Internet Archive's arcademanuals collection on 14 August 2026 and identified from their title page. ⚠️ The items declare no licence.

Sources & attribution

  • Wikipedia — CP System III (architecture, security, suicide, 2007 crack) — CC-BY-SA — https://en.wikipedia.org/wiki/CP_System_III
  • Darksoft — CPS-3 multi kit — to reference
  • Arcade-Projects — CPS-3 de-suicide / multi — to reference

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.

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