DD11-B

This document is an Engineering Change Order (ECO) log for the Digital Equipment Corporation's DD11-B, a component within the PDP-11 Family of processors, detailing several modifications and corrections issued between March 1973 and January 1974.

The key changes include:

• DD11B-A0001 (Mar-73): Addressed a grounding issue where logic/groundplane was not tied to chassis ground. The correction involved adding a #24 gauge wire, to be immediately implemented in-plant and retrofitted in all existing DD11-B units.
• DD11B-00002 & -0002A (Aug-73): Corrected a problem where wires were being cut by Faston power lugs and wire wrap pins. The solution involved adding plastic wire shields and rerouting wires. A subsequent ECO (DD11B-0002A) clarified the implementation to include units not yet checked out and all new DD11-B builds.
• DD11B-D0003 (Nov-73): Provided additional backplane wiring necessary for the DU11-EA option, enabling synchronous Current Mode operation. This required specific wire additions and was to be retrofitted in DD11-B back panels when the DU11-EA option was used, phasing in by January 1974.
• DD11B-00004 (Jan-74): Mandated the provision and installation of a new power harness for PDP-11 systems with fifteen-pin power distribution. This applied to specific PDP-11/35, /40, /45, and /50 systems based on their serial numbers.

Each entry specifies the problem, the required correction, and the effectivity (in-plant and/or field retrofit, including specific models, serial numbers, or dates where applicable).