VT100

This document serves as a Mini Maintenance Hardware Guide for the VT100 terminal, outlining procedures for troubleshooting, operating summary, testing, video alignment, and module removal/replacement.

The guide begins with Troubleshooting (Chapter 1), detailing how to use the terminal's internal self-test features, including keyboard LED and display error codes, to isolate failures to specific field replaceable units (FRUs). It also provides a basic troubleshooting chart for common VT100 issues and a list of recommended spare parts.

The Operating Summary (Chapter 2) explains the SET-UP mode, a special operational mode that allows users to configure terminal features. This includes enabling/disabling features, setting a 20-character answerback message, saving settings to nonvolatile memory, recalling saved settings, and resetting the terminal.

Testing the VT100 (Chapter 3) covers three internal self-test programs: the Power-Up test (which verifies RAM, nonvolatile RAM checksums, ROM checksums, and keyboard function), the Data Loopback test (which checks transmit and receive lines using an external connector), and the Video Adjust test (which displays a full screen of 'Es' for display adjustments). The chapter also discusses fatal and nonfatal error codes and mentions the use of a PMK04 tester.

Video Alignment (Chapter 4) provides detailed procedures for adjusting the video monitor's settings, such as brightness, focus, yoke, vertical height, horizontal width, centering, and linearity (vertical and horizontal), as well as vertical hold, often utilizing specific alignment templates.

Module Removal and Replacement (Chapter 5) presents step-by-step instructions for disassembling and reassembling various mechanical subassemblies of the VT100, including the access cover, terminal controller board, advanced video board, current loop board, keyboard components, top cover, video monitor board, flyback transformer, bottom cover, power supply, DC power harness, and the CRT monitor assembly. This chapter includes important safety warnings, particularly concerning the high voltage of the CRT anode.

VT100 Options (Chapter 6) describes the installation and checkout procedures for optional features, specifically the Advanced Video Option (which adds capabilities like 24 lines of 132 characters and alternate character sets) and the 20 mA Current Loop Option (for short-distance communication without a modem).

Finally, Physical/Functional Block Diagram (Chapter 7) indicates the provision of diagrams to illustrate the interconnections of the terminal's components.