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Midway — Y-Unit, Wolf-Unit, V-Unit, Seattle, Zeus

Beyond the T-Unit (Mortal Kombat II), Midway/Williams fielded a whole lineage: Y-Unit (Smash TV, MK1), Wolf-Unit (MK3, NBA Hangtime), V-Unit (Cruis'n USA), then 3D with Seattle (SF Rush) and Zeus/Vegas (MK4, Gauntlet Legends, NFL Blitz). From the TMS34010 to MIPS + 3dfx Voodoo.

The generations

Hardware Year CPU / GPU Games MAME driver
Y-Unit 1990 TMS34010 Smash TV, Total Carnage, Trog, Mortal Kombat (1992), Terminator 2 midway/midyunit.cpp
T-Unit 1992 TMS34010 @ 50 MHz MK II, NBA Jam — see the dedicated page midway/midtunit.cpp
Wolf-Unit 1994 TMS34010 + DCS Mortal Kombat 3 / UMK3, NBA Hangtime, Rampage World Tour, WWF WrestleMania midway/midwunit.cpp
V-Unit 1994 TMS32031 Cruis'n USA, Cruis'n World, Offroad Challenge, War Gods midway/midvunit.cpp
Seattle 1996 MIPS R5000 + 3dfx Voodoo San Francisco Rush, Wayne Gretzky 3D Hockey, Mace, CarnEvil, Biofreaks midway/seattle.cpp
Zeus / Vegas 1998-99 MIPS + Zeus GPU Mortal Kombat 4, SF Rush 2049, Gauntlet Legends/Dark Legacy, NFL Blitz, Cruis'n Exotica midway/vegas.cpp
  • Y/T/Wolf: the TMS34010 (graphics-CPU) and its digitised actors — the whole 2D Mortal Kombat saga.
  • Seattle/Zeus: Midway moves to PC-like (MIPS + Voodoo) for 3D (SF Rush, Gauntlet Legends).
  • Sound: Williams ADPCM (early) → DCS (ADSP-2105, from MK II/Wolf on).

Notable games

Smash TV (1990), Mortal Kombat 1-4, NBA Jam, Cruis'n USA (1994), San Francisco Rush, Gauntlet Legends, NFL Blitz, CarnEvil, Rampage World Tour…

Common faults

Symptom Likely cause Lead
Lost settings/scores Flat/leaking CMOS battery Replace + clean corrosion
No sound DCS (ADSP-2105) or Williams ADPCM Sound-board diagnosis
Corrupt sprites/3D TMS34010 / Voodoo (Seattle/Zeus) Video diagnosis per generation
HDD dead (Zeus/Vegas) IDE disk on late games Image the disk
No image Power, 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.
  • Hard disk ⚠️: a perishable medium — image the drive before it fails, then consider an SSD/CF replacement → PCB preservation hub.
  • Scan rate 📺: a TMS34010-based board: the screen configuration is programmed by the game in the graphics controller and does not appear in the driver — not measured here. In practice these boards stay at standard ~15 kHz. (Derived from the architecture documented above.) → tri-sync and upscalers.
  • FPGA / emulation: see the Emulation & FPGA section below.

Repair (technician)

  • TMS34010 (Y / T / Wolf-Unit): CPU-graphics — corrupt image = GSP / video RAM / blitter. V-Unit = TMS32031 (Cruis'n 3D).
  • DCS sound (ADSP-2105) on Wolf-Unit/later: an ADPCM daughterboard to diagnose separately.
  • Capacitors: recap. ROM board / EPROM sockets: contacts / turned-pin socket.

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

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.

→ Full catalogue: service manuals, wiring & game manuals

Emulation & FPGA

  • Emulation: MAME (midyunit.cpp, midwunit.cpp, midvunit.cpp, seattle.cpp, vegas.cpp).
  • FPGA / MiSTer: no core (TMS34010 / MIPS+Voodoo too complex) → MAME.

EPROM repair

Y-Unit (Mortal Kombat II, NBA Jam TE) = TMS34010 + ROM board. V-Unit (Cruis'n USA), Wolf-Unit, Seattle (SF Rush), Zeus (MK4): newer (PC-like / mask ROM). Repair = mask ROM + boot EPROM on the ROM board.

Lineage

Descends from the Williams 6809 (same WMS house); the T-Unit has its own page. The 3D era = MIPS + Voodoo (like Konami Hornet, Sega Lindbergh).

Photos / assets

(To add: Y-Unit MK1, Seattle/Zeus board, Voodoo, CMOS battery.)

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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