Engineering Change Order Log for PDP-11/40 Processor

This document serves as an Engineering Change Order (ECO) Log for the Digital Equipment Corporation's PDP-11/40 processor, detailing various modifications and corrections implemented between August 1972 and January 1974. Each entry outlines a specific problem, its required correction, and implementation details.

The changes primarily cover:

1. Documentation and Parts List Updates: Correcting drafting errors, adding/deleting prints, revising drawing directories, and updating parts lists to reflect accurate components and configurations.
2. Hardware Design Improvements: Addressing issues such as fan wiring radiating AC line noise, modifying power harnesses to prevent arcing and ensure proper power distribution, replacing panel mounting brackets and spacers, adding cable clamps, and incorporating new bezels and mounting hardware.
3. Assembly and System Configuration: Introducing new assembly configurations (e.g., -FA, -FB, -FE, -FF, -CS, -CT, -AG, -AD), updating system checkout procedures, and adding necessary components like additional power regulators.
4. Manufacturing and Field Implementation: Specifying in-plant effectivity dates for changes, ensuring new designs are integrated into production, and outlining field effectivity for retrofitting existing units to address potential issues like power fail problems.

Overall, the log demonstrates a continuous effort to refine the PDP-11/40 processor's design, enhance its reliability, and maintain accurate documentation throughout its production lifecycle.