PA611-R

This document is an Engineering Change Order Log (DEC-O-LOG) from Digital Equipment Corporation, identified as PA611-R for the PDP-11 Family's Typesetting Reader Control.

Issued in August 1973 under change number PA611R-B0001, it details two corrections:

1. Correction 1: To fix errors in the UNIBUS connector print.
2. Correction 2: To address a floating pin J1 issue that arises when M7821 modules replace M7820 modules. The solution involves connecting pin J1 to BUS NPR L. This wiring change affects all units using either M7820 or M7821 modules. Crucially, M7820 modules are not to be proactively replaced with M7821 modules unless the M7820 module fails.

The change's effectivity specifies:

• In-plant: Immediate retrofit (-03).
• Field: Immediate retrofit for units using M7821 modules; retrofit at the next Preventative Maintenance (PM) for units using M7820 modules.

The estimated time for installation and testing is 0.5 hours, and the kit contents include F1025 and FCO/Prints.