LQP8/78 Printer Systems Technical Manual

This document is a comprehensive technical manual for the Digital Equipment Corporation LQP8/78 Printer Systems.

It provides detailed information for both users and field service personnel, covering the LQP8 and LQP78 printer models. The system primarily consists of an LQPO1 serial (daisy wheel) printer, an LQP8-E controller (or direct interface for the LQP78 model), a power supply, and an enclosed desk, designed for use with PDP-8 family computers.

Key aspects covered include:

• Description: Physical characteristics, performance specifications (up to 45 characters per second, high-quality printing), components (print wheels, ribbon cartridges, forms tractor options).
• Installation and Checkout: Step-by-step guidance for unpacking, cabling, installing the controller module, paper loading, and initial system verification.
• Operation: Details on operating controls and indicators, procedures for loading paper, changing ribbons and print wheels, and energizing/de-energizing the printer.
• Programming: In-depth explanations of Input/Output Transfer (IOT) instructions for controlling printer functions such as paper movement, carriage movement, and character printing, including programming considerations and examples.
• Technical Description: Detailed theory of printer operation and controller interface signals.
• Service: Extensive procedures for preventive maintenance (cleaning, lubrication), diagnostic testing (including the DHLQA diagnostic program), fault isolation, troubleshooting, and precise alignment/adjustment of mechanical components (e.g., print wheel to hammer, platen, carriage, ribbon height).
• Appendices: Additional technical data such as modified ASCII codes, character positions on print wheels, interface wiring details, integrated circuit information, and troubleshooting flowcharts, as well as specific details on the LQP8-F serial printer variant.

Published with editions from 1976 to 1980, this manual serves as a complete guide for understanding, operating, and maintaining these vintage printer systems.