W850

This document is a schematic diagram for the I.O. CONNECTOR W850, created by Digital Equipment Corporation in 1966. It is provided for test and maintenance purposes, noting that the circuits are proprietary.

The schematic details two main connectors, J1 and J2, which are internally structured as J1A/J1B and J2A/J2B respectively. Both connectors exhibit a similar architecture:

• Diode-based Input/Output Paths: Input lines (labeled with alphanumeric codes like ACO, ADO, AEO, or color codes like WHT, RED, SLATE) pass through pairs of diodes (primarily D662 / IN645) to various output lines (similarly labeled with colors or alphanumeric codes like O BC, O BD, O BE).
• Power and Filtering: Each connector incorporates power supply filtering and regulation circuitry connected to -15V and GND, utilizing multiple D662 diodes, capacitors (specified as .01 MFD, 100V, 20%), and 270 Ohm, 2W resistors (R1, R2). Additionally, -3V STRATE power rails are present, also regulated by arrays of diodes (D52-D49, D48-D45), capacitors, and resistors (R3, R4).

General specifications state that unless otherwise indicated, diodes are D664 (which the conversion chart identifies as IN3606), and capacitors are .01 MFD, 100V, 20%. The conversion chart also indicates D662 as IN645.