VT72T/VOL 2

This document provides a comprehensive set of field maintenance prints and specifications for the Digital Equipment Corporation VT72T/VOL 2 system. It details the system's construction, operation, maintenance, and testing procedures across several key areas:

• System Overview and Specifications: The VT72 is described as an LSI-11 based intelligent terminal, featuring a 15-inch alphanumeric display with 24 rows of 80 characters, a 256-character set, and various display modes (blink, bold, underline, half reverse video). It utilizes an LK05 keyboard with unique features and includes capabilities for smooth "panned" scrolling and character detection.
• Module Descriptions and Parts Lists: Detailed parts lists and descriptions are provided for core components such as the VT72T Unit Assembly, 32K 16-bit MOS Memory, ASYN Line Interface (DLV11-F), VT71 Control Module (M8657), VT71 Video Module (M8658), VT71 Bus Grant Board, LSI-11 CPU (M7270), and the H780 Power Supply.
• Technical Schematics and Layouts: Extensive circuit diagrams and physical layouts are included for the memory modules, asynchronous line interface, VT71 control and video modules, and the power supply, detailing jumper configurations, IC types, and connectivity.
• Assembly and Packaging Instructions: The document includes instructions for the VT72T terminal unit assembly and packaging, along with detailed diagrams of harnesses and cables for power, keyboard, speaker, and video.
• Programming Information: Specifics are provided for programming the VT72, including the Command and Status Register, hardware vectors, text format, and character data format, outlining how software interacts with the terminal's hardware.
• Acceptance Procedures: A significant portion is dedicated to acceptance testing procedures for the VT72/t, detailing on-line and off-line self-test diagnostics, required test equipment, software, and specific steps for testing with PDP-11 (DH11, DL11) and PDP-8 (KL8-J, DH8-E) systems, including run times and error criteria.