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Sega System 32 converts (de-suicide & conversion)

The System 32 has a suicide battery: the program is encrypted and decrypted via a security module/daughter board. Dead battery = dead game. Good news: all games have been patched/decrypted by the community — you de-suicide by burning decrypted ROMs (often just one) and removing the module. Conversions are done via a compatible ROM board.

Field Value
Platform Sega System 32 / Multi 32
Type de-suicide (decrypted ROMs) + conversion via ROM board
Difficulty 🟡 (1-ROM de-suicide) → 🟠 (full conversion)
Suicide? Yes — encrypted program, key in the battery-backed security module

Architecture

Block System 32 Multi 32
CPU NEC V60 @ 16.1 MHz NEC V70 @ 20 MHz
Sound CPU Z80 @ 8.05 MHz same
Sound YM3438 + Ricoh RF5C68 MultiPCM (YMW-258-F)
Screen 1 monitor 2 monitors (dual screen) + more RAM

V60/V70 share the same instruction set (V60/V70/V80 compatible), but Multi 32 ≠ System 32 hardware-wise (see cross-platform conversion below).

Suicide & de-suicide

  • The program is encrypted; a daughter board / security module holds the key (battery-backed SRAM). Dead battery = no decryption = mute board.
  • De-suicide: burn decrypted ROMs and remove the security module (the board no longer needs to decrypt).

Often just ONE ROM to change

In most cases, one ROM must be replaced by its decrypted version for the game to run without the module — sometimes a second to fix the checksum. The community has released the patched ROMs for all System 32 games.

Converting to another game

Conversion happens at the ROM board level, provided you use the right board type:

ROM board type Chips
"Big" 18 chips
"Small" 20 chips

Each type is compatible with certain titles. To convert:

  1. Check the target game uses the same ROM board type (Big/Small) as your donor.
  2. Burn the target game's decrypted ROMs (no security module needed).
  3. Fit them on the ROM board, set the DIPs.
  4. Test (image, YM3438/RF5C or MultiPCM sound depending on platform).

Which EPROM to replace a blown chip?

(Board architecture & faults: Sega System 32 PCB.)

Size → EPROM mapping (8-bit 27C parts, DIP32 unless noted):

Dump size Density 8-bit EPROM (DIP32) 16-bit / mask variant (DIP40/42)
64 KB 512 Kbit 27C512
128 KB 1 Mbit 27C010 / 27C1001
256 KB 2 Mbit 27C020 / 27C2001
512 KB 4 Mbit 27C040 / 27C4001 27C400 / 27C4096 (mask pinout)
1 MB 8 Mbit 27C080 / 27C801 27C800 (16-bit)
2 MB 16 Mbit 27C160 (1M×16) / 27C322 (2M×16)

epr- = reprogrammable EPROM · mpr- = factory mask ROM

In the ROM sets, epr-xxxxx = EPROM (directly replaceable with the same density). mpr-xxxxx = factory mask ROM: if it dies you replace it with an equivalent-density EPROM, but the mask pinout ≠ EPROM (especially ≥ 4 Mbit and 16-bit) → you often need a pinout adapter (mask → 27C160/27C400).

Worked example: Golden Axe — The Revenge of Death Adder

GARDA is NOT an ordinary jumper conversion — it's a protected game

Golden Axe: The Revenge of Death Adder uses a dedicated ROM board (833-8933-02) + a protection sub board (834-8529-02, a custom V25 running encrypted code, EPROM epr-14468-02 at U3) + an A/D board (837-7968, for the analog levers). → You therefore cannot convert a generic System 32 (ROM board 837-7429) into GARDA by reflashing EPROMs: you need the GARDA ROM board + V25 sub board + A/D board trio. The realistic technician path: repair / reflash an existing GARDA board, you don't "build" one from another game. (Verified: MAME sega/segas32.cpp.)

EPROM locations on a GARDA board (World Rev B set, ga2) — to replace a chip:

Function Socket Original ROM Size Type EPROM replacement
V60 program P0 IC17 epr-14961b 128 KB EPROM 27C010
V60 program P1 IC8 epr-14958b 128 KB EPROM 27C010
V60 data D0 IC18 epr-15148b 256 KB EPROM 27C020
V60 data D1 IC9 epr-15147b 256 KB EPROM 27C020
Sound Z80 (bank 0) IC36 epr-14945 64 KB EPROM 27C512
Sound (banks) IC35 / IC34 / IC24 mpr-14944/43/42 1 MB ea mask 27C801 (+ adapter)
V25 protection U3 (sub board) epr-14468-02 64 KB EPROM 27C512
Tiles IC14 / IC5 mpr-14948/47 2 MB ea mask 27C160 (+ adapter)
Sprites IC32/30/28/26/31/29/27/25 mpr-14949…14956 2 MB ea mask 27C160 (+ adapter)
  • Don't mix revisions: World Rev B (ga2, epr-1496xb/1514xb), US Rev A (ga2u, epr-1495xa/1514xa), Japan (ga2j) have different program epr-s — keep a consistent set.
  • Program/sound epr-s are reburnable; the mpr-s (graphics/PCM sound) are huge mask ROMs: in practice you reuse the originals and only reburn if one dies.

Game by game: program EPROM per socket (System 32 / Multi 32)

Program/data sockets (reburnable epr- EPROMs) per game, with density → the EPROM to burn. Reference World/Export set; US/JP revisions have different epr-s (same density). (Source: MAME sega/segas32.cpp.)

Game romset Program sockets (EPROM) Note
Air Rescue arescue IC13/IC6 = 27C010 · IC14/IC7 = 27C040
Alien³: The Gun alien3 IC17/IC8 = 27C020 · IC18/IC9 = mask 27C040 data = mask ROM
Arabian Fight arabfgt IC8 = 27C010 · IC18/IC9 = 27C020 protected — V25 sub board epr-14468-01
Burning Rival brival IC8 = 27C010 · IC18/IC9 = 27C040
Dark Edge darkedge IC8 = 27C040
Dragon Ball Z V.R.V.S. dbzvrvs 27C040
F1 Exhaust Note f1en IC6 = 27C010 · IC14/IC7 = 27C020
F1 Super Lap f1lap IC17/IC8 = 27C010 · IC18/IC9 = 27C020
Golden Axe: Revenge of Death Adder ga2 IC17/IC8 = 27C010 · IC18/IC9 = 27C020 protected — V25 epr-14468-02 (detailed above)
Holosseum holo 27C010
Jurassic Park jpark IC8/IC18/IC9 = 27C040
Rad Mobile radm IC21 = 27C010 · IC37/IC38 = 27C040
Rad Rally radr IC21 = 27C010 · IC37/IC38 = 27C040
SegaSonic the Hedgehog sonic IC17/IC8 = 27C010 · IC18/IC9 = 27C020
Slip Stream slipstrm IC6/IC14/IC7 = 27C040 jumper reference game below
Spider-Man spidman IC13/IC7/IC14/IC6 = 27C010
Super Visual Football / J.League svf / jleague IC17/IC8 = 27C010 · IC18/IC9 = 27C040
Multi 32 — Title Fight titlef IC37/IC40 = 27C020 dual screen
Multi 32 — OutRunners orunners IC37/IC40 = 27C010 dual screen
Multi 32 — Stadium Cross scross IC37/IC40 = 27C020 · IC36/IC39 = 27C040 dual screen
Multi 32 — Hard Dunk harddunk IC37/IC40 = 27C020 dual screen

What this tells you concretely

  • Only 2 System 32 games are protected (V25 sub board): Arabian Fight and GARDA. Everything else is an "ordinary" ROM-board conversion (reburn the epr-s, reuse the graphics mpr- masks, set the jumpers).

  • The Multi 32 games (dual-screen: Title Fight, OutRunners, Stadium Cross, Hard Dunk) use a different socket layout (IC37/IC40…) — see the Multi 32 note below.

System 32 ROM board jumpers (837-7429-01)

On the generic ROM board (non-protected games), jumpers JP1–JP32 configure the EPROM size each socket bank accepts. The position depends on the density fitted — refer to the board silkscreen and the EPROM type used.

MAME reference table (Slip Stream example; "may vary depending on ROM types used"):

JP1: 2-3 JP9: 1-2 JP17: 1-2 JP25: 2-3
JP2: 2-3 JP10: 2-3 JP18: 2-3 JP26: 1-2
JP3: 2-3 JP11: 1-2 JP19: 1-2 JP27: 1-2
JP4: 1-2 JP12: 1-2 JP20: 2-3 JP28: 2-3
JP5: 2-3 JP13: 1-2 JP21: 1-2 JP29: 1-2
JP6: 2-3 JP14: 2-3 JP22: 2-3 JP30: 2-3
JP7: 1-2 JP15: 2-3 JP23: 1-2 JP31: 1-2
JP8: 2-3 JP16: 2-3 JP24: 1-2 JP32: 1-2

Generic ROM board EPROM locations (silkscreen → IC → type):

Role Silkscreen IC EPROM type
CPU program P0 / P1 IC13 / IC6 27C4002 / 27C4000
CPU data D0 / D1 IC7 / IC14 27C4000 (4 Mbit)
Sound SND0 / SND1 IC35 / IC31 27C010 / 27C4000
Scroll (SCR0-3) SCR0…3 IC38/34/29/25 27C4000
Sprites (OBJ0-7) OBJ0…7 IC36/32/27/23/37/33/28/24 27C4000

(837-7429-01 = standard System 32 ROM board. GARDA and other protected games have their own ROM board — see above.)

System Multi 32 → System 32 (complicated)

Converting a Multi 32 game to plain System 32 (or the reverse) is trickier: different hardware (V70 vs V60, dual screen, MultiPCM vs YM3438/RF5C, RAM). It's not a simple ROM-board swap — for well-documented cases only.

Before / after

  • De-suicide: a suicided board (dead battery) lives again, battery-less, with 1 (or 2) decrypted ROMs.
  • Conversion: a game's ROM board becomes another game of the same board type.

Where to read more

Open-source FPGA core archived here

An FPGA (MiSTer) recreation of System 32 / Multi 32, SystemVerilog sources to compile: s32.tar.gz · README — upstream: https://github.com/meathax/s32. We host no arcade ROMs.

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.

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