Timing Diagram Horizontal Circuitry
As previously stated, the Vertical Address Counter (4D) is clocked by HSYNC*. Thus, for every horizontal line of 32 RAM Accesses, the counter is advanced for another 32 RAM Addresses. The displayed portion of the Vertical Address Counter range is 224 lines. However, the counter actually counts through 256 states. Inverter 3F is connected to the clear pins of the Vertical Address Counter but it does nothing. Video Address bus bits AB5 through AB12 are generated by...
42 Video Board
NOTE The Video Board Schematic is presented at the end of this manual. The video board is the most complex in the system and will be explained in the greatest detail. A video image is displayed on the CRT screen by sequentially reading out a group of Random Access Memory locations synchronously with the video beams, and then shifting the bytes out to the CRT a bit at a time. The resolution of the system is 256 dots or picture elements (pixels) per line, by 224 lines per frame. For every...
41 Cpu Board
The control portion of the CPU Board is the Z-80 microprocessor. Basically, the Z-80 performs the following functions It fetches an instruction, or command from a program memory and then executes that instruction. Usually, the processor fetches and executes instructions in a sequential manner and it does this quite rapidly. The ability to do tasks quickly is one of the two significant features of the microprocessor. The other feature is the ability to modify the order of program execution as a...
Section 1 Installation
This game has been STERN final tested and is ready to play, but on all games there are seme items that must be checked after shipment. Making these visual inspections may avoid time consuming service work later. Minor troubles caused by abusive handling in shipment are unavoidable, such as cable connectors that may have become loosened. Check ALL CONNECTORS on the game to make sure they are firmly seated. Check to make sure that the game control boards are firmly seated (See Figure B). Examine...
