Typesetting Reader Control

This Engineering Change Order (ECO) document outlines two specific technical modifications for the PDP-11 family:

1. Correction 1: Fixes errors on the UNIBUS connector print.
2. Correction 2: Addresses floating pin J1 on M7821 modules, which are used as replacements for M7820 modules. It specifies connecting pin J1 to BUS NPR L and provides instructions for the associated wire addition (A01S2 to A02J1).

The document mandates immediate retrofitting for units using M7821 modules and schedules retrofits at the next Preventive Maintenance (PM) interval for units using M7820 modules. The estimated time to install and test these changes is 0.5 hours.