PC05

This document is an Engineering Change Order Log (ECO-LOG) from Digital Equipment Corporation for the PC05 Paper Tape Reader/Punch. It details several engineering changes (ECNs) and their associated problems and corrections for all processor types.

The specific changes listed are:

1. PC05-00024 (March 1972): Addresses the redesign of the punch motor driver, eliminating certain electronic parts. The correction involves revising prints to depict a new Triac Driver and updating the assembly title.
2. PC05-00025 (December 1972): Focuses on cost reduction by replacing the expensive aluminum bezel with a plastic bezel, using an ultrasonic weld for attachment.
3. PC05-D0026 (September 1973): Covers two issues:
   • Problem 1: The potential for a 4 AMP fast-blow fuse F2 to blow when turning the PC05 on/off. The correction is to replace it with a 4 AMP slow-blow fuse (part #90-07220) on the power regulator, with a field retrofit recommended if symptoms are present (estimated 0.3 hours for installation and test).
   • Problem 2: The omission of the Illustrated Parts Breakdown (IPB) from the drawing set. The correction is to add the IPB to drawing A-AL-PC05-0-05.

The document is copyrighted © 1974, printed in the U.S.A., is Revision O, and is Page 4.