M7284

This document is an Engineering Change Order Log for the M7284 DA11-F Bus Window Control module, designed for PDP-11/45 processors. It records a series of engineering changes and corrections made between January and December 1973 to address various issues.

Key problems and their solutions include:

• Capacitor Polarity & Etch Errors (JAN-73): Correcting incorrect polarity for capacitor C72 and fixing an etch error related to C71.
• Vector Timing (FEB-73): Addressing a timing issue where the vector was asserted too early relative to BUS BUSY and INTR signals by adding an R/C delay circuit.
• Schematic and Parts List Errors (OCT-73): Correcting general circuit schematic errors and adding omitted capacitor C70 to the parts list for new boards.
• Insufficient Setup Time (NOV-73): Increasing the time delay after the START OK signal by changing the value of capacitor C55 and adding address selection jumpers.
• Missing Etch Run (DEC-73): Fixing an ungrounded Q8 emitter due to a missing etch run, which caused modules to fail certain tests, by adding a wire connection.

Each entry specifies the nature of the problem, the corrective action, and instructions for implementation, including in-plant rework and field service requirements, often with estimated installation and test times.