G350

This document is a proprietary electronic schematic diagram, dated 1970 and copyrighted by Digital Equipment Corporation (DEC), for a circuit board designated "HEAD 1 VER G350" (drawing number G350-0-1, Revision E). It is provided for test and maintenance purposes.

The circuit operates on +5V and -15V power rails and primarily utilizes 2N2904A PNP transistors (as default), D672 diodes (as default), and various resistors and capacitors. Key components include:

• An input conditioning stage for a "WRITE ENABLE H" signal, employing a DEC3009B transistor (EIA 2N30008) and a 2200pF capacitor.
• A large bank of ten repeated or very similar two-stage PNP transistor driver/buffer circuits, handling input signals labeled from AE2 to AV2 and producing output signals like BE2 to BS2.
• Extensive power supply decoupling and filtering, using multiple 47uF capacitors connected to various labeled +5V, -15V, and signal lines.

The entire circuit interfaces with other systems via a 28-pin connector (part number 1210067-0). Default component specifications are provided for resistors (680 ohms, 1/4W, 5%) and capacitors (0.01uF, 100V, 20%), though many components on the schematic have explicitly stated different values.