| Testing Interface used by GLS1 Electronics: | |
| The star field in the background screen of the Galaga video game PCB can be tested in full by using this module designed specifically for this purpose. Any output pin on the 74LS259 chip position 5K on the video board can be checked and verified individually. These outputs go directly to the custom "05" chip, which is the star field generator. This is one of the tests a Galaga video PCB will undergo during repair at GLS1 Electronics. | |
| Manual
selection of input variables: By adjusting the slider on the right, the address bus inputs A, B, and C count in binary, selecting which "Q" output the data input "DI" will be transferred to when the "Port" signal is pulsed. Watchdog reset must be cycled during these tests, and is handled internally by selecting the check box for this function. Automatic selection of input variables: By selecting "use file", pre-determined values are applied to the 74LS259 during this test. (Star speed fast, star speed slow, etc.) Black = low state White = high state Green = pulse condition |
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| An example of the actual module used for these tests is available here: Download 74LS259 module | |