Engineering Change Order Log

This document is a 1974 Engineering Change Order (ECO) log for the G109 Control and Data Loop modules, applicable to the PDP-11 and PDP-15 families. It lists specific engineering changes to address hardware issues, such as board etch updates, component substitution, physical mounting failures, and timing margin adjustments (e.g., memory cycle times and slave sync issues). Each entry details the problem, the required correction, and the effectivity (in-plant and field rework instructions).