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Sega Hikaru

Sega's high-end 3D in 1999: a NAOMI evolution that doubles everything (two SH-4s, two AICAs, doubled RAM/VRAM) and was the first arcade board capable of Phong shading. Born to render the fire/water of Brave Firefighters. Expensive, few games, rare hardware — emulation (Demul) is the key to preservation.

Hikaru main board.
Hikaru main board. Photo uploaded by Mikel to Sega Retro, a site under CC BY 4.0.

Identification

Field Value
Manufacturer Sega
Year 1999 (Brave Firefighters)
Type high-end 3D (between NAOMI and NAOMI 2)
Media ROM board
I/O JVS
Resolution 640×480

Architecture

Block Chip Clock Role
CPU ×2 Hitachi SH-4 200 MHz ~360 MIPS / 1.4 GFLOPS; geometry + game
GPU custom Sega Phong shading (an arcade first), light/particle effects
Sound ×2 ARM7 + Yamaha AICA 45 MHz 64 ADPCM voices (double the NAOMI sound)
Memory doubled RAM/VRAM vs NAOMI
Media ROM board

The Hikaru doubles most of the NAOMI's components and adds Phong shading — developed by Sega specifically to render the fire, water and particles of Brave Firefighters, beyond the original NAOMI. High cost → a small catalogue.

Notable games

Brave Firefighters (1999, first game), Airline Pilots / Aero Dancing, Planet Harriers, Cyber Troopers Virtual-On Force, Star Wars Racer Arcade, NASCAR Arcade, Get Bass 2… (about ten titles).

Faults & repair

Symptom Likely cause Lead
No image / corrupt 3D SH-4 / custom GPU / RAM Block-by-block diagnosis; rare customs
No sound (one channel) one of the 2 AICAs / ARM7 Sound-stage diagnosis
ROM board not read contacts Cleaning
Reboots PSU capacitors Recap
Dead controls JVS I/O / harness JVS diagnosis

Rare and expensive hardware → priority on saving dumps and software preservation.

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 📺: ~31.72 kHz / 60.1 Hz — high resolution (VGA class), ⚠️ you need a 31 kHz / tri-sync monitor; a 15 kHz chassis is incompatible → tri-sync and upscalers. (Computed from the MAME sources — sega/hikaru.cpp — pixel clock ÷ htotal.)
  • FPGA / emulation: see the Emulation & FPGA section below.

Repair (technician)

  • Rare custom GPU (dual SH-4, geometry): corrupt 3D = video RAM + buffers first, the custom last (a very rare donor — a niche platform).
  • Sound: 2× ARM7 + AICA (64 voices) — diagnose the sound stage.
  • ROM board: contacts → clean. Capacitors: recap PSU + audio.

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

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: historically very hard; Demul is the reference emulator (the only one supporting the Hikaru; near-complete support in recent builds). No FPGA core (2× SH-4 + custom GPU, out of budget).

Lineage

Between the NAOMI (1998) and the NAOMI 2 (2000). Same sound family (AICA) as the NAOMI/Dreamcast. Contemporary with the last Model 3 games.

Photos / assets

(To add: Hikaru board, dual SH-4, ROM board, JVS I/O.)

Sources & attribution

Image:

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.