M952

This document is a proprietary schematic and parts list for a "LEVEL TERMINATOR M952" module, copyrighted by Digital Equipment Corporation in 1970, intended for test and maintenance purposes.

The main schematic details four identical circuit blocks (E1, E2, E3, E4), each consisting of a resistor (150 Ohm) and multiple D662 diodes arranged in an array. These blocks receive power from a +5V supply, which is filtered and regulated to provide +3.5V and +0.7V reference levels using various 0.01uF and 39uF capacitors. The circuits likely function as diode termination networks or level shifters.

Key specifications and components highlighted are:

• Diodes: D662 (equivalent to IN645), with 20 used in total.
• Resistors: 150 Ohm, 1/4W, 5% tolerance, with 4 used.
• Capacitors: Primarily 0.01uF, 100V, 20% disc type (9 used) and 39uF, 10V, 10% tantalum type (2 used) for power supply filtering.
• Integrated Circuits (ICs): Four DEC 2501 ICs are listed, suggesting that the E1-E4 blocks might be packaged as, or incorporate, these specific ICs.
• Power: +5V, generating +3.5V and +0.7V within the circuit.
• Construction: Mounted on an etched circuit board, with additional components like a "Flip Chip Magenta" handle and eyelets.

The document also includes a "Transistor & Diode Conversion Chart" and details for module history and layout.