UKVAC Tech Pages
Beginner's Arcade Machine Primer

Nearly every UKVACer will have a Arcade Machine in some shape or form, and although the all look different, when it boils down to it they all share the same architecture. This article introduces very briefly what is contained within a cab.

This article is the first in an ever-expanding series which attempts to introduce to the newcomer the fundamentals of a cab, its contents, how to restore and maintain them, etc. 

[Cabinet Side View] Cabinet Of course, the cabinet comes in many shapes and sizes, and can be grouped into three types upright (depicted), cabaret (small upright), or cocktail (tabletop). There are two other descriptors used, Generic (normally meaning a JAMMA mass-produced) cabinet, or a dedicated - the latter customarily having a unique shaping, artwork and wiring to suit one type of game.

Game Board The heart of the game. This board contains all of the game logic, ROM data, RAM, CPU, etc. This is the piece that the rest of the cabinet talks to. All controller inputs and outputs come through here.

Monitor: This is the piece you'll recognize immediately. All arcade machines have them, and with only three exceptions, they've remained fundamentally unchanged since the first arcade game, Computer Space. The only real exceptions to the standard monitor lineage are the Atari medium res monitors, and older Vector monitors, colour and B & W.

Control Panel: The part you've spent the most time fondling. Can consist of buttons, wheels, pedals, dials, knobs, etc etc etc.

Power Supply This is the part that supplies power to the rest of the cab. Almost all games use standard voltages, +5, +12, and -5 volts, although occasionally theres -12v.


There isn't much wiring inside an arcade cabinet, despite what you may have seen when you looked into one. Most all wires run from the game board to the component in question. The basic groups of wires are:

Display: There are five wires here, and in some instances, six. One wire each for the Red, Green, and Blue video information, as well as Ground and Sync. In some cases, usually older boards, there are two sync wires: one for Horizontal and one for Vertical Sync.

Control Panel: This bundle contains one wire for a common connection, and one each for every control direction, button, or control. Double this for a two player cabinet, and you can see that a bundle of up to thirty wires isn't hard to attain.

Power Supply: From the power supply you need at least one wire (And up to four or more) for each voltage connected. These will provide power to the game board, and to any other part of the game needing power. Atari Games use a "Audio/Regulator" in-between the Power supply and Game Board as this controls the voltages.
[Cabinet Wiring Diagram]

Other than the basic wiring and main pieces, alls thats left are the extra bits and pieces that may or may not be there/ present, and so they have been grouped together below:

[Cabinet Side View #3] Marquee: This normally has the name of the game and some artwork for most dedicated cabinets and are also collected by many. Its not unusual for these to be illuminated by a light behind, and a speaker beneath.

Coin Door: When a machine was in-service, this lockable door was used to take coins from the player via illuminated coin slots, pass it through a Coin Mech to verify it was the correct coinage and access how many credits it was worth, then drop it into a tub to be collected later by the operator.

Around this area can also be found additional game adjustment tools, such a free credit switch, test switch, service switch, volume control, manual odometer coin counters, etc etc.

 These parts usually serve a function necessary in the arcades, but aren't strictly necessary for the home user. When buying a used machine privately, it's very common to find kicked-in or destroyed parts that don't affect game play.

 


In the next section, we will look at the wiring harness using the  JAMMA Connector as the example.


Thanks go two Game Station X at www.gamesx.com for the artwork and basic text of this page!