POWER INVERTER B681

This document is a proprietary schematic diagram for a Power Inverter B681, copyrighted by Digital Equipment Corporation in 1964 and intended for test and maintenance purposes. The circuit features four identical stages (Q1-Q4), each comprising a transistor, a .01 MFD capacitor, and two D-664 diodes, along with multiple associated resistors (primarily 1,500 ohms). The output section includes a series of eight diodes (D9-D16) connected to a -15V line. General component specifications are provided: resistors are 1/4W, 5% (or 100, 1/4W, 10% for unindicated values); capacitors are MMFD; transistors are DEC2894-2B; and diodes are D-662. A conversion chart further clarifies that DEC2894-2B transistors have no direct equivalent listed, while D662 diodes convert to IN645 and D664 diodes to IN3606.