H780-C, -D, -H, -J, -K, -L Power Supply User's Manual

This document is a user's manual for the H780 series power supply, manufactured by Digital Equipment Corporation (DEC).

Key points:

• Purpose: The H780 power supply is designed to provide DC operating power for LSI-11 or PDP-11/03 computer systems.
• Models: Six options are available (H780-C, -D, -H, -J, -K, -L), differing primarily by AC input voltage (100-127 Vac or 200-254 Vac) and the inclusion of a console type (none, master, or slave).
• Console Functionality: Master consoles (H, J) offer full control with switches for DC ON/OFF, LTC ON/OFF, and ENABLE/HALT, along with indicators for RUN, DC ON, and Spare. Slave consoles (K, L) only have a DC ON indicator.
• Configuration: The H780 can be used as a stand-alone unit or mounted to an H9270 backplane. It includes built-in cooling fans for itself and connected modules.
• Power Output & Regulation: It utilizes high-frequency, low-voltage switching regulators for its primary +5V and +12V outputs, and provides -15V and +5V for internal circuits. Maximum output power is 110W.
• Protection: The power supply incorporates comprehensive protection mechanisms against overcurrent, overvoltage (crowbar circuits), short-circuit, slow voltage buildup, and low line voltage. Input protection is via a fuse (5A for 115V, 2.5A for 230V).
• System Integration: It generates essential logic signals for proper power sequencing of the LSI-11/PDP-11/03 system, including power status (BPOK H, BDCOK H), line time clock (BEVNT L), and halt/run control (BHALT L, SRUN L). It supports master-slave configurations for controlling multiple power supplies.
• Installation & Adjustment: The manual provides detailed instructions for installation, including connecting the AC line cord, enabling stand-alone operation, mounting to a backplane, and establishing master-slave connections. It also outlines procedures for adjusting the +5V and +12V DC outputs using a DVM and oscilloscope.