LA36/LA35 DECwriter II

This document is a maintenance manual for the LA36/LA35 DECwriter II printer terminals, providing comprehensive information for their operation, installation, checkout, servicing, and theory.

The LA36/LA35 DECwriter II is a fast, quiet, 300 baud hard-copy printer terminal designed for remote or local input/output. It produces hard copies and up to 5 duplicates on tractor-driven continuous forms, supporting standard ASCII characters at various baud rates (110, 150, 300 baud). The manual details the printer's physical characteristics, functional description (including character printing, paper feeding, ribbon drive, carriage servo, and power supply systems), and technical specifications.

Key sections of the manual cover:

• Installation and Checkout: Step-by-step procedures for unpacking, initial setup, and verifying proper operation, including jumper configurations for different logic board models (M7722, M7723, M7728).
• Operation: Detailed descriptions of LA36 and LA35 operator controls and indicators, paper loading, ribbon installation, and a programmer's guide for transmitting and receiving characters and commands.
• Theory: In-depth explanations of the printer's microprogram (including INIT, POSIT, SPEED, INPUT, BELL, PRINT, LINE FEED, LCV, and NEXT routines), scratch pad memory, control logic, keyboard system, data communications interface, clock logic, and printer mechanism (carriage, ribbon, and paper feed subsystems).
• Upgraded LA36: Information on significant equipment changes, model variations, easy identification of logic boards, and M7728 logic board functional descriptions and cabling configurations.
• Electrical and Mechanical Servicing: Procedures for various electrical tests (off-line and on-line) and detailed mechanical servicing for components like the printer housing, print head, timing belt, carriage assembly, ribbon drive, idler gear, stepping motor, transformer, and line filter assembly.
• Adjustment Procedures and Lubrication: Guides for encoder adjustment, print head adjustment, carriage shaft adjustment, print bar adjustment, paper guide and printer mechanism adjustment, paper out switch adjustment, ribbon tension adjustment, ribbon drive assembly adjustment, idler gear assembly adjustment, bumper assembly adjustment, and lubrication points.
• Appendices: Engineering drawings, an illustrated parts breakdown, and reference data including abbreviations and a signal glossary.

The document emphasizes safe practices, proper assembly, alignment, and troubleshooting to ensure optimal performance and longevity of the DECwriter II.