M152

This document is a proprietary schematic diagram for a Digital Equipment Corporation (DEC) "2 Decoders M152" module, copyrighted in 1970 and intended for test and maintenance purposes.

The schematic details a digital circuit primarily consisting of:

• Two independent decoding sections: Each section is enabled by a control line (D2 and V2 respectively).
• Integrated Circuits (ICs): Nine ICs are used per module. E9 (DEC1074H20) likely acts as an enable/control gate, driving multiple DEC1074H21 ICs (E1-E8) that perform the primary decoding functions, generating various outputs (e.g., M2-J2, S2-N1).
• Discrete Components: Various resistors (330 Ohm and 750 Ohm) and capacitors (0.01uF and 150uF) are incorporated for power conditioning and other circuit requirements. General specifications for resistors and capacitors are provided.
• Power and Ground: Pin 7 is designated as ground and Pin 14 as +5V for all ICs.

The document also includes:

• A parts list detailing all components, including the ICs, resistors, capacitors, an etched circuit board, and documentation for module history, assembly/drilling, and X-Y coordinate locations.
• Notes regarding unused pins (F2 and U1) being designated for backplane twisted pair grounds.
• Revision and drawing information, including the designer (Nancy Moore, 1970).