M802

This document is an Engineering Change Order Log (ECO Log) from Digital Equipment Corporation, dating from 1970-1972. It details various problems and their engineering solutions for the M802 12-Bit Latching Relays Module, which is designed for use with PDP-8 and PDP-11 processors.

Each entry in the log outlines a specific problem, its code, and the required corrective action. The issues addressed include:

• Excessive signal loading on the START signal input (M802-00001).
• Electrical noise from high voltage switching causing data interaction, requiring etch line adjustments and filtering (M802-A0002).
• Timing problems with the DATA STROBE signal due to non-retriggerable one-shot circuits, necessitating an IC replacement (M802-00003).
• Subsequent corrections for previous changes, such as adding a voltage source for the new one-shot IC (M802-00003A) and rectifying incorrect parts counts in the bill of materials (M802-00003B).

The log provides details on the problem, the specific correction, and notes on effectivity (e.g., "rework immediately," "phase-in," "documentation change only").