LG12 Text and Graphics Printer

This document is a comprehensive maintenance manual for the LG12 Text and Graphics printer, intended for field service technicians. It provides a detailed overview of the printer's functional elements, including the control panel, common controller board (CCB), mechanism driver board, hammer driver board, auto-ranging power supply, and print mechanism. The manual explains the principles of line matrix printing and character generation, followed by sections on preventive maintenance, covering routine cleaning.

A significant portion is dedicated to troubleshooting, offering detailed tables for various fault messages (e.g., "48 Volt Failed," "Paper Jam," "Shuttle Jam") and guidance for symptoms not indicated by fault messages, along with troubleshooting aids like diagnostic self-tests and confidence checks. Furthermore, the manual includes extensive adjustment procedures for critical mechanical components such as hammer springs, magnetic pickups, paper feed belts, and platen gaps. Finally, it outlines step-by-step replacement procedures for numerous parts, including blower assemblies, fans, circuit boards, motors, and the hammer bank, supplemented by illustrated parts lists. Appendices provide wire data, a glossary of technical terms, PROM and chip locations, torque specifications, metric conversion tables, and detailed printer specifications.