With this manual you received two large sheets that contain the wiring and schematic diagrams for the Asteroids game. Sheet 1, Side A, includes information that shows the arrangement of these dia grams. These diagrams include information that explains the functions of the circuits and defines inputs and outputs.
Atari's Asteroids is a microprocessor-controlled game. The microprocessor is contained on the game PCB. The game PCB receives switch inputs from the control panel and coin door. These inputs are processed by the game PCB and output to the TV monitor, Regulator/Audio PCB and control panel.
The TV monitor is an X-Y monitor. Therefore, the monitor receives signals for the X, Y and Z axes. Since the location of the beam in the monitor is totally controlled by the X- and Y-axis outputs of the game PCB, the game PCB does not contain a standard sync circuit. The X- and Y-axis inputs to the monitor step in increments of 1024 steps for the X (horizontal) axis and 768 steps for the Y (vertical) axis. The Z axis merely controls the intensity of the beam.
The Regulator/Audio PCB performs two funtions: 1) regulates the +10.3 VDC from the power supply to +5 VDC, and 2) amplifies the audio output from the game PCB. The +5 VDC from the Regulator/ Audio PCB provides most logic power to the game PCB. The audio output from the Regulator/Audio PCB directly drives the game speaker and is controlled by the volume control mounted inside the coin door.
The Power Supply is the source of all voltages in the game. These voltages are protected by five fuses in the fuse block on the Power Supply chassis. The primary winding of the Power Supply transformer is protected by the cartridge-type fuse in the power supply chassis.
Figure 12 illustrates the distribution of power in this game. Figure 13 illustrates the distribution of signals.
Figure 13 Signal Distribution
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