RK11-D

This document is an Engineering Change Order (ECO) log for the RK11-D Disk Control unit, applicable to PDP-11 Family and PDP-15 processors, with entries dating from June 1972 to January 1974.

The logged changes address a range of issues, primarily focusing on:

• Documentation Corrections: Updates to parts lists, legends, tooling information, engineering specifications, unit assembly drawings, and wiring tables to correct errors or add missing details.
• Wiring and Back Panel Modifications: Changes related to module wiring (e.g., M7256, M7254, M7255), adding ground tabs and wire shields to back panels, correcting signal routing (e.g., DR BUS DC LO, BU AC LO), and ensuring proper grounding (logic to chassis).
• Hardware Component Updates: Introduction of new power harnesses for specific PDP-11/40 and PDP-11/45 system configurations.
• Corrections to Previous ECOs: Several entries are follow-ups to earlier changes, rectifying mistakes in prior instructions or clarifying requirements.

Each entry specifies the problem, the required correction, and detailed "in-plant" and "field" effectivity instructions, often dictating immediate retrofits, phase-ins for specific production builds (e.g., Canada builds, units leaving Westfield/Kanata after certain dates), or applicability to specific serial number ranges or backplane revisions.