Difference between revisions of "H742 Power Supply"
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| − | The '''H742 Power Supply''', and later revision '''H7420''', is a modular [[power supply]] system from [[Digital Equipment Corporation|DEC]], used with the [[BA11-F Mounting Box]]. Among other uses, | + | The '''H742 Power Supply''', and later revision '''H7420''', is a modular [[power supply]] system from [[Digital Equipment Corporation|DEC]], used with the [[BA11-F Mounting Box]]. Among other uses, that mounting box is used in [[PDP-11/40]], [[PDP-11/45]] and [[PDP-11/70]] systems to hold the [[Central Processing Unit|CPU]]. |
The H742/H7420 runs off standard wall [[Alternating current|AC]]; it can be [[jumper]]ed to use either 110V or 220V supply. | The H742/H7420 runs off standard wall [[Alternating current|AC]]; it can be [[jumper]]ed to use either 110V or 220V supply. | ||
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Generally the [[power harness]] supports only limited options as to which regulator can be in which spaces; e.g. the later -11/40 harness mandates that A, B and C hold [[H744 +5V Regulator]]s, D holds an [[H745 -15V Regulator]], and E may hold either an H745 or [[H754 +20V, -5V Regulator]]. | Generally the [[power harness]] supports only limited options as to which regulator can be in which spaces; e.g. the later -11/40 harness mandates that A, B and C hold [[H744 +5V Regulator]]s, D holds an [[H745 -15V Regulator]], and E may hold either an H745 or [[H754 +20V, -5V Regulator]]. | ||
| − | A 5409730 board in the H742, replaced by an | + | A [[DEC Power Line Monitor|5409730 board]] in the H742, replaced by an 5411086 board in the H7420, supplies a modest amount of +15V [[Direct current|DC]] power to various backplanes mounted in the BA11-F, along with a [[line time clock]] signal, and AC and DC 'power OK' signals. |
| − | The harness used [[DEC power distribution connectors]] to provide power to the backplanes; it normally used the [[DEC standard power wire colour coding]]. | + | The harness from the H742/H7420 (the same for both, it appears) used [[DEC power distribution connectors]] to provide power to the backplanes; it normally used the [[DEC standard power wire colour coding]]. |
The H742/H7420 did not support the [[Remote Switching Control Bus]]; the H742/H7420 was generally plugged into an [[861 Power Controller]], which did have the remote control capability. | The H742/H7420 did not support the [[Remote Switching Control Bus]]; the H742/H7420 was generally plugged into an [[861 Power Controller]], which did have the remote control capability. | ||
| − | A later version of the basic H742 is the H742A; the difference is not yet known. For the H7420, in addition to the board above, the differences | + | A later version of the basic H742 is the H742A; the difference is not yet known. |
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| + | For the H7420, in addition to the board above, the differences seem to be mainly mechanical: a larger cooling fan; a change in the orientation of the +15V supply board from horizontal to vertical (perhaps to make room for the fant); and the sheet metal enclosure holding the fan, board and transformer is a single unit, not two bolted together, as in the H742. | ||
==See also== | ==See also== | ||
Revision as of 20:00, 10 June 2019
The H742 Power Supply, and later revision H7420, is a modular power supply system from DEC, used with the BA11-F Mounting Box. Among other uses, that mounting box is used in PDP-11/40, PDP-11/45 and PDP-11/70 systems to hold the CPU.
The H742/H7420 runs off standard wall AC; it can be jumpered to use either 110V or 220V supply.
The main transformer in the H742/H7420 provides 20-30V AC to several DEC standard modular regulators (up to five, in spaces numbered 'A' through 'E') mounted in the H742/H7420, which provide other voltages such as +5V to the backplanes in the mounting box.
Generally the power harness supports only limited options as to which regulator can be in which spaces; e.g. the later -11/40 harness mandates that A, B and C hold H744 +5V Regulators, D holds an H745 -15V Regulator, and E may hold either an H745 or H754 +20V, -5V Regulator.
A 5409730 board in the H742, replaced by an 5411086 board in the H7420, supplies a modest amount of +15V DC power to various backplanes mounted in the BA11-F, along with a line time clock signal, and AC and DC 'power OK' signals.
The harness from the H742/H7420 (the same for both, it appears) used DEC power distribution connectors to provide power to the backplanes; it normally used the DEC standard power wire colour coding.
The H742/H7420 did not support the Remote Switching Control Bus; the H742/H7420 was generally plugged into an 861 Power Controller, which did have the remote control capability.
A later version of the basic H742 is the H742A; the difference is not yet known.
For the H7420, in addition to the board above, the differences seem to be mainly mechanical: a larger cooling fan; a change in the orientation of the +15V supply board from horizontal to vertical (perhaps to make room for the fant); and the sheet metal enclosure holding the fan, board and transformer is a single unit, not two bolted together, as in the H742.
