LP37 Line Printer

This document is a comprehensive service manual for the Digital Equipment Corporation LP37 Line Printer, designed for interfacing, adjusting, troubleshooting, maintaining, and repairing the printer. It covers both old and new style printer models, specifically addressing Customer Services engineers.

The manual begins with a general description of the LP37 Line Printer, detailing its high-speed impact band printing capabilities, print mechanism components (paper feed, ribbon, meter package, band system, hammerbank, and cooling system), technical specifications, and internal electronics. It also outlines the printer's fault monitoring system, including soft and hard errors, and describes the universal power supply assembly and operator control panels.

Subsequent chapters delve into the functional description of the printer's interface, covering signal definitions, I/O connector pin assignments, signal circuits, and handshaking protocols. Extensive troubleshooting information is provided, including LCD error/fault messages, second-level diagnostics, specific fault procedures (e.g., airflow, band motor, paper, hammer), inoperative printer procedures, and instructions for resistance and voltage checks across various components.

The document also provides guidance on adjustments and preventive maintenance, listing special tools required and detailing routines for optimal performance, such as hammer flight time, transducer phasing, and band tracking adjustments. Finally, it offers step-by-step procedures for the removal and replacement of Field Replaceable Units (FRUs), from top covers and circuit boards to specific motor assemblies and internal components. Appendices provide additional troubleshooting and removal/replacement procedures specific to new style printers with removable cabinet side panels, along with comprehensive spare parts lists.