General Information

The block diagram in Figure 17 shows the major functional parts of the Drag Race™ game and their interconnections. Note that the game printed circuit board sends a composite video signal to the TV monitor and a separate audio signal to each speaker.

The general information about the Drag Race™ game given here provides a background for understanding certain parts of Chapters 1 and 2.

The game's TV monitor is a self-contained transistorized television monitor supplied to Atari by Motorola. Because thecomposite video signal sentto the monitor by the game control circuitry differs in certain important respects from the signal derived from commercial TV broadcasts, the picture appearing on the screen is unlike that of a home TV set and the monitor does not produce any sound.

Figure 17 Functional Block Diagram of "Drag Race" Game

The game's composite video signal is constructed to produce only four video levels, instead of the more or less continuous shades of gray seen on a home TV screen. These four levels are named white, gray, charcoal and black.

This chapter of the manual gives technical descriptions of game circuitry regarded as field-repairable. Correction in the field of troubles traced to certain portions of the circuitry on the PCB may require replacement of the entire board.

The drawings included in this chapter supplement the text given here. Figure 20 is a seven-sheet schematic diagram of the circuitry on the printed circuit board. Figure 21 is the PCB assembly drawing and parts list showing the locations of the components called out on the schematic. The position of each integrated circuit device is identified by a column letter designation (A through R), and by a row number designation (0 through 9). Figure 22 is a harness schematic that shows the wiring connections between the PCB, player controls, and other components mounted inside the cabinet. A schematic diagram of the TV monitor's circuitry is also included as Figure 23.

On the PCB schematic the symbol P (appearing at various inputs to logic gates and other integrated circuits) indicates a connection to +5 volts through a pull-up resistor.

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