G888

This document is a circuit schematic for the MANCHESTER READER/WRITER G888 (Part Number G888-0-1), produced by Digital Equipment Corporation and copyrighted in 1969.

The schematic is provided solely for test and maintenance purposes, highlighting its proprietary nature.

Key features and components of the circuit include:

• Active Components: Operational amplifiers (E1, E2 are MC1709CG), NAND gates (E3 is DEC7400N), and several transistors (e.g., Q1 DEC3009B, Q2-Q5 DEC6534C), along with various diodes (e.g., D662, D664, D670, IN753A).
• Passive Components: Numerous resistors (generally 1/4W, 5%, with R7 being a Cermet Helitrim potentiometer), and capacitors (generally 100V, 5%, with values ranging from .01MFD to 100MMF, and specific Mylar and electrolytic types).
• Power Rails: The circuit operates with +5V, -15V, and GND connections.
• Component Specifications: A general note specifies typical ratings for capacitors (100V 5%), diodes (D664 unless otherwise indicated), resistors (1/4W 5%), and transistors (DEC1008-S unless otherwise indicated). Pin assignments for the E3 NAND gates are also provided.
• Conversion Chart: A "Transistor & Diode Conversion Chart" maps Digital Equipment Corporation (DEC) part numbers to their EIA equivalents (e.g., DEC3009B to 2N3009B, D664 to IN3606).