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Atari — vector games (Asteroids, Tempest…)

A family apart: Atari's vector cabinets (late 1970s / early 80s) — Asteroids, Lunar Lander, Battlezone, Tempest, Star Wars, Gravitar. No pixels: a vector (XY) monitor draws lines. Repair revolves around that particular monitor and its high voltage.

PCB Atari Tempest (vectoriel)

PCB Atari Tempest (vectoriel) — photo by thermionics, CC BY 2.0 (Wikimedia Commons).

Identification

Field Value
Manufacturer Atari
Era ~1979-1985
Display Vector XY (B&W or colour), no raster
Generator DVG (Digital Vector Generator) then AVG (Analog Vector Generator)
Monitor B&W XY (Asteroids, Battlezone) · colour XY = Wells-Gardner 6100 or Amplifone ("Quadrascan")

Architecture (board side)

Block Element Role
CPU MOS 6502 (@ ~1.5 MHz) game logic; often a 2nd 6502 dedicated to sound
Vector generator DVG then AVG reads a vector list (display list) in RAM and drives the monitor's X/Y DACs + intensity
Math Box (Star Wars, Battlezone, Red Baron) bit-slice multiplier (AM2901) computes the 3D projection of the vectors in real time
Sound POKEY (× n) / TIA / discrete effects + music

The principle: instead of a TV (raster) scan, the board sends the monitor X/Y coordinates and an intensity; the beam traces segments directly between points — hence the sharp, bright lines of Asteroids, Tempest, Star Wars, Battlezone.

DVG vs AVG

Generator Intensity Colour Games
DVG (Digital Vector Generator) fixed (on/off) B&W Lunar Lander, Asteroids, Asteroids Deluxe, Battlezone, Red Baron
AVG (Analog Vector Generator) variable (per-vector brightness) colour possible Tempest, Space Duel, Gravitar, Black Widow, Star Wars, Major Havoc, Quantum

The AVG is the major evolution: each segment can have its own brightness and colour (gradients, depth cueing), impossible on the DVG.

The "Math Box" (3D games)

Battlezone (1980) and especially Star Wars (1983) add a Math Box: a small AM2901 bit-slice calculator that performs the 3D projection's multiplies/divides far faster than the 6502 — which is what makes Star Wars' wireframe flight possible.

The vector monitor (the heart of the matter)

A vector game needs a dedicated XY monitor (not a raster one):

  • B&W XY: Asteroids, Battlezone, Lunar Lander.
  • Colour XY: Wells-Gardner WG6100 or Amplifone — Atari branded them "Quadrascan". These are the most fragile and the #1 source of faults.

An XY monitor cannot simply be replaced by an LCD: you need either a repaired real XY CRT or an XY→raster converter (community solutions).

Common faults

Symptom Likely cause Lead
Distorted / missing lines XY deflection stage, cold joints Reflow, deflection diagnosis
Dead screen (HV ok) Vector stage / dead caps Recap + diagnosis
Fixed bright dot ("spot") Spot-killer / deflection failure ⚠️ power off (phosphor burn risk), repair first
Wrong colours (WG6100) Colour stage / convergence Adjustments, recap
Board: no image Power, DVG/AVG, contacts Diagnosis

High voltage (CRT) & spot-killer

An XY monitor = a high-voltage CRT: discharge the tube before any work. If a fixed, very bright dot appears, cut power immediately — the stationary beam burns the phosphor in seconds. The spot-killer circuit is meant to prevent this; if it fails, that's the priority.

Repair & preservation

  • Recap + reflow of the XY monitor (WG6100 / Amplifone) — the central topic; capacitor kits and repro deflection boards exist (active community).
  • DVG/AVG diagnosis for board-side drawing faults.
  • Reference emulation: MAME (Atari vector drivers).
  • FPGA / MiSTer: cores exist for several Atari vector games (Asteroids, Lunar Lander, Battlezone, Tempest, Black Widow…) — the vector render is rebuilt and shown as raster.

EPROM repair

6502 (Asteroids, Tempest) / 68000 (Star Wars) program in 2716 / 2732 / 27128 by era. The heart is the vector generator (DVG/AVG) + Math Box (Star Wars), not the EPROM — see the architecture above.

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 📺: not applicable — VECTOR display. There is no line-by-line scanning and no horizontal frequency: the beam draws the segments directly. These machines require a vector monitor and cannot be connected to a raster chassis, a tri-sync or an upscaler. See the repair section for the deflection electronics.
  • FPGA / emulation: see the Emulation & FPGA section below.

Repair (technician)

  • ⚠️ High-voltage XY vector monitor (WG 6100 / Amplifone) → CRT safety; a static spot burns the phosphor (cut immediately).
  • DVG / AVG: distorted/missing lines = the vector generator (digital DVG or analog AVG) + deflection; the Amplifone and WG6100 have known HV faults (deflection transistors) → recap + diagnose.
  • Slapstic (protection) on some games: check before suspecting the logic.
  • Sound: dedicated 2nd 6502 + POKEY — diagnose the sound stage.

→ Methods: CRT safety · PCB fault-finding · Recap · EPROM

Expected clocks — measurement table ✅

Values extracted from the MAME sources for this platform. On a scope or frequency counter, a clock that is missing or off-value points straight at the crystal, the divider or the chip at fault — the fastest starting point on a dead board.

Component Expected clock Role
M6502 1.512 MHz CPU

How to read this table

Several values for one component = several board variants in this family (or several instances of the chip clocked differently). These frequencies are those of the clock signal at the component's input, not of its original crystal — on many boards the clock is divided down from a single master crystal.

Archived original schematics ✅

Manufacturer schematics for games in this family, archived locally (so they do not depend on a third-party site staying up). They give the board's real functional breakdown: clock tree, address decoding, video stage, sound stage, power supply — exactly what you need to trace a missing signal back to its source.

Scope and limits

A schematic applies to the game and revision named. Within one family the general breakdown (buses, decoding, sound/video stages) carries over from board to board, but component references and custom chip pinouts do not transpose between titles. Use it as a map of the logic, not as a cross-reference table.

Source: the Arcade Game Manuals collection on the Internet Archive. Manufacturer documents with no explicit licence, kept here for preservation (machines out of service for over 25 years).

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 asterock
Setting Position Options (default in bold)
Language SW:1,2 English · French · German · Italian
Lives SW:3,4 2 · 3 · 4 · 5
Records Table SW:5 Normal · Special

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

Photos / assets

(To add: WG6100/Amplifone monitor, vector board, DVG/AVG, Math Box.)

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.