Typesetting Punch Control

This Engineering Change Order (PA611-P) covers two primary technical corrections for the PDP-11 Typesetting Punch Control:

1. Correction 1: Fixes errors in the UNIBUS connector print.
2. Correction 2: Addresses a floating pin (J1) issue when replacing M7820 modules with M7821 modules. It specifies connecting pin J1 to BUS NPR L via a single ADD/DELETE wire change (A01S2 to B02J1).

The document provides specific implementation instructions for both in-plant production and field units, noting that field replacement of M7820 with M7821 should only occur upon failure of the original unit.