GT40 Graphic Display Terminal

This document is Volume 1 of the maintenance guide for the GT40 Graphic Display Terminal. It covers:

• General Description: An overview of the high-performance graphic display system operating through a VT40 (PDP-11/05) computer, including descriptions of its eight basic components (CPU, Display Processor, Communications Interface, Memory, Keyboard, CRT Monitor, Light Pen, and Power Supply).
• Installation: Procedures for site planning, unpacking, and initial setup, including connecting the various components and verifying cables.
• Theory of Operation: A detailed operational breakdown of the display processor, timing, mode control, vector generation, character generation, and analog circuits. It also covers the DL11 Asynchronous Line Interface and LK40 keyboard operations.
• Maintenance: Preventive and corrective maintenance, including electrical and power supply checks, troubleshooting charts, and assembly replacement instructions for the VR14 CRT display.
• Engineering Drawings: A list of major engineering drawings and related documentation for the system.