Besides being incredibly
addictive,
BattleZone really set the stage for an entire
genre of vids that came after. Looked at one way, it was the parent of the entire
first-person shooter genre. The reason it was able to pull off the
computationally-hard (especially for the time) trick of
immersing the player was strictly due to its utilization (like many Atari vids of the time) of vector-based graphics.
The cabinet and inside layout of the BattleZone machine is a bit different from most vids of the era. First of all, since the game is meant to be played with ones' eyes up against the 'scope (really a piece of molded plastic comprising the frontpanel, but not completely blocking the view so as to allow kibitzing), it's much taller than most vids of the era. In order to allow a 90-deg viewing angle without mounting the awkward, heavy monitor at the top of the cabinet (and hence making the cabinet not only unstable but potentially lethal) Atari placed the monitor around midpoint in the machine, facing directly up and buried within. This allowed them to limit the hardware at the top of the machine to a 45-degree mirror behind the viewing area.
In addition, to both increase stability and allow the vertically challenged (typically through youth) to play the machine, a 'step' was added. The step is an entirely separate construction, of surprisingly heavy marine-quality plywood or particleboard. It mounts against the base of the machine at the front, and is secured through the expedient of two long steel bolts which are then secured from within the cabinet. Many surviving BattleZones lack the step, as it was easily damaged, lost or knocked off while moving the game.
Inside the cabinet, BattleZone has a fairly typical layout. Starting a the bottom, there is a power distribution PCB mounted to the bottom of the cabinet frame. This contains the 120VAC converter as well as the audio hardware, and is hooked to the dual speakers in the front of the cabinet just below the monitor. The brains of the box are mounted to the sidewall up the left side of the machine (viewed from the front), and consist of two PCBs with an edge-connector wiring harness connecting them.
The top PCB (I think) is BattleZone itself, containing logic for gameplay, audio, control inputs, video hardware and the like. The lower one, however, is an interesting artifact for the time; it's essentially a vector calculations MPU (called 'the math box' by Atari personnel). This allowed the minimal hardware of the machine (6502 CPU and various glue logic) to maintain such smooth performance - it would simply hand off the desired matrix transforms to the math box, which would generate the X,Y coordinates passed to the video hardware (remember, this is a vector or XY game - the monitor does not raster scan, but instead scans as an oscilloscope would, from vertex to vertex of the required screen shapes).
The math box was common to several games of the time, including BattleZone and its aerial cousin Red Baron. This allowed for economies of scale in the production and design of the machines, as well as a more important characteristic for a working vid - maintenance. Since the math was all being done on this board, most of the serious heat generated by the machine's silicon (as opposed to power hardware) came from this board. Since this heat lowered the lifespan of chips, it made replacing the most likely to fail parts of the motherboard quick, easy and cheap enough for field service.
If you have multiple
BattleZone and/or
Red Baron machines, this is a handy diagnostic; if your game starts displaying peculiar graphics artifacts, try swapping the math box and determining if the artifacts follow the math box or the motherboard.
One additional trait of this machine and its ilk should be mentioned. As the boards contained socketed components (allowing board-level repairs), they were extremely sensitive to overheat. The heat of the math box especially would cause the chip packaging tines (legs) to flex, and the chips would slowly unseat themselves. If your machine shows artifacts in the geometry of on-screen objects, try the following tricks:
- The Pencil: Using the eraser end of a pencil (for both insulation and grip) simply press firmly down (down w/r/t the board) on the middle and two ends of each chip on the board (you can do this while the machine is running). If your problem is due to heat and chips unseating, you will eventually poke the problem chip and the video artifacts will suddenly go away. Shut down the machine and reseat the chip; ideally, remove it, clean the tines with the same pencil eraser to remove oxidation and thus resistant patches, and reseat. You may need to do this for multiple chips.
- Chip Cooler: While the game is operating, take an aerosol can of chip cooler and, in turn, give each chip on the board a good shot of it while watching (or likely having a friend watch) the video. Same rules apply; if you find a particular chip which when cooled changes the display (I won't say fixes, because your problem may involve multiple chips) then mark it for reseating and cleaning. Note: Chip cooler used to be available at Radio Shack, but may have fallen prey to the Ozone Defenders. Although it's more dangerous, you can use photo air - turn the can upside down and from a distance allow liquid air to hit the chip in small doses. Careful, though; if you use too much, you might crack the packaging or otherwise damage the board!
- Check the Harness: The multiple boards of this machine are interconnected with a single spaghetti-like wiring harness which attaches to edge connectors on each board. Since the game is passing fairly high voltages through this harness (for a data connection as well as through the power lines) the aluminum traces on the edge connectors can become oxidized. In addition, frequent cycling of the connectors can scrape the traces and damage their connectivity. Try removing the harness and cleaning both the traces on the board and the insides of the connectors - you can use a Q-tip and alcohol. Do this with the machine OFF!
A standard warning applies here. Monitors are EXTREMELY dangerous. Even when off, cathode ray tubes can and do retain charges of up to 19,500 volts; simply coming into contact with the tube's hardware or even the boards/wiring can cause this juice to ground through you (trust me, I've done it, it ain't no fun). That much power can do to you much what a defibrillator does, and shouting CLEAR! won't help you.
The Atari vector games (XY games) are probably the most collectible early arcade machines. While the monitors are notoriously quirky, especially in the color versions, there are 'get-well kits' made that contain newer, higher-rated versions of the parts likely to fail. The most well-known are called 'Zanen Kits' after the manufacturer, Zanen Electronics. Although they require soldering/desoldering expertise to install, an XY monitor so modded will be highly resistant to failure. The reason for this, in addition to better tech in recent parts, is that Atari had all kinds of motivation to make these things cheap (they were envisioned as lasting a couple years at the outside; they're made of particleboard for lord's sake so DON'T GET THEM WET) and the components picked show it.