Selftest

The G-80 system contains a built-in self-test system, activated by depressing the red self-test switch located on the CPU Board. If the cover to the G-80 card cage is in place, the switch can be activated by putting a pen or pencil through the hole provided on the cover. 4. Video RAM and Hardware multiplier Individualized diagnostics descriptions and procedures 1. CPU RAM - tests all RAM on CPU card before proceeding, system needs to use this RAM for stack and variables during other tests so if...

Color Xy Monitor And G80 Circuit Description

To begin our discussion of the Color X-Y Monitor, let's first pay tribute to the other kind of monitor - the raster-scan. As you may remember from your knowledge of raster-scan displays (like those in a TV), that the electron-beam inside the tube always moves in a predictable way. That is, it always starts at the top left of the screen and scans across it, forming a pattern of horizontal lines on the inside surface of the tube as it moves downward. When it gets to the bottom, the beam is forced...