H765 Power System
The H765 Power System is a modular power supply system from DEC, used in the BA11-K mounting box. In addition to main memory and device controllers on other PDP-11's, the BA11-K was used to hold PDP-11/04 and PDP-11/34 systems.
The H765 supplies a modest amount of +15V DC power to various backplanes mounted in the BA11-K, along with a line time clock signal, and AC and DC 'power OK' signals.
It also supplies 20-30V AC to several DEC standard modular regulators (up to four, in spaces numbered '1' through '4') mounted in the H765, which provide other voltages such as +5V to the backplanes in the mounting box.
Generally the power harness supports only a fixed arrangement as to which regulator can be in which spaces; e.g. the BA11-K harness mandates that #2 and #3 hold H744 +5V Regulators, #1 holds an H745 -15V Regulator, and #4 may hold an H754 +20V, -5V Regulator.
When the BA11-K is used in custom configurations to hold systems (such as the MJ11 memory system and MK11 memory system), other regulator configurations may be used, along with a custom harness; e.g. the MJ11 calls for two H744's and two H754's.
The harness uses DEC power distribution connectors to provide power to standard backplanes.
The H765 supported the standard DEC Remote Switching Control Bus, so it could be turned off and on from a power switch elsewhere.
