M969

This document is a proprietary electrical schematic from Digital Equipment Corporation, copyrighted 1971, intended for test and maintenance purposes. It details the design of "24 Level Terminators and Thermistor" circuits.

The schematic primarily features:

1. 24 Level Terminators: Organized into three similar blocks (E1, E2, E3), each handling 8 signal lines. Each termination circuit within these blocks consists of diode arrays connected to +5V, +3.5V, and +0.7V supply rails. Associated components include 150 Ohm resistors (R1, R2, R3) and various capacitors (C1-C6 and C9 typically 0.01uF, 100V, 5%).
2. Thermistor Circuit: A separate circuit (U1) features a DEC1310071 thermistor with a 1K Ohm resistor (R4), likely for temperature sensing or compensation.
3. General Component Specifications: Unless otherwise indicated, capacitors are 0.01uF, 100V, 5%; diodes are D662; and ICs are DEC2501. Specific bulk capacitors C7 and C8 are 39uF, 10V, 10%.

A parts list further details components, including 3 I.C.s (DEC2501M), 1 thermistor, 3 resistors, 15 D662 diodes, various capacitors, and an etched circuit board. The document also includes a Transistor & Diode Conversion Chart, showing D662 corresponds to an IN3606 EIA part number.