H720 Power Supply - Revision history

Jnc: New cat

2023-07-10T12:49:21Z

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2022-06-16T12:15:35Z

New cat

Jnc: /* External links */ +FMPS, manual

2022-01-23T13:46:17Z

‎External links: +FMPS, manual

Jnc: A decent start

2018-12-01T12:25:54Z

A decent start

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The '''H720 Power Supply''' was a [[power supply]] produced by [[Digital Equipment Corporation|DEC]], principally for the [[BA11-C Mounting Box|BA11-C]] and [[BA11-E Mounting Box]]es, the two earliest earliest standard [[system unit]] [[backplane]] [[mounting box]]es for the [[PDP-11]] line.

They were also produced in a rack door-mounted configuration, for use with some larger [[peripheral]] [[device controller]]s. For the mounting box application, it was a separate unit, mounted transversely at the back of the box.

There were six different variants, -A through -F; three sets of two, of which the earlier in each set (e.g. -A) was configured for 110V, and the latter (e.g. -B) was configured for 220V. (The input transformer had two input windings, which could be connected in series or parallel, depending on the desired voltage.)

The three sets were the earlier mounting box version (-A and -B), the door-mounted version (-C and -D), and the later mounting box version (-E and -F).

The later mounting box versions of the H720 differed in:

* Use of a [[circuit breaker]] rather than a [[fuse]] on the main [[alternating current|AC]] input;
* It had a pair of connections to the standard DEC [[Remote Switching Control Bus]], so it could turn other units off and on with its power switch;
* The power switch on the front of mounting box uses these, instead of a switch in the main AC input;
* A temperature sensor to power down the unit in case of over-heating;
* Improved +5V output capability.

It supplied regulated -15V (10A), and +5V (16A, -A/-B; 22A -E/-F), and also i) a 60Hz signal for a [[line time clock]], and ii) ACLO and DCLO power status signals.

It contained an input [[transformer]], and a [[printed circuit board|PCB]] which produced all the outputs. The actual [[power supply]] at both regulated [[voltage]]s was a [[switching power supply|switching supply]], for improved [[EI conversion]].

The H720 was 8" high, 16-1/2" wide, and 6" deep, and weighed 30 lbs.

[[Category: DEC Hardware]]

← Older revision		Revision as of 12:49, 10 July 2023
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	* [http://www.bitsavers.org/pdf/dec/pdp11/pwrSupply/H720_EngrDrws.pdf H720 power supply and mounting box engineering drawings] (DEC-11-HR5B-D)		* [http://www.bitsavers.org/pdf/dec/pdp11/pwrSupply/H720_EngrDrws.pdf H720 power supply and mounting box engineering drawings] (DEC-11-HR5B-D)

−	[[Category: DEC ~~Electrical~~]]	+	[[Category: DEC Power Supplies]]

← Older revision		Revision as of 12:15, 16 June 2022
Line 27:		Line 27:
	* [http://www.bitsavers.org/pdf/dec/pdp11/pwrSupply/H720_EngrDrws.pdf H720 power supply and mounting box engineering drawings] (DEC-11-HR5B-D)		* [http://www.bitsavers.org/pdf/dec/pdp11/pwrSupply/H720_EngrDrws.pdf H720 power supply and mounting box engineering drawings] (DEC-11-HR5B-D)

−	[[Category: DEC ~~Hardware~~]]	+	[[Category: DEC Electrical]]

@@ Line 17: / Line 17: @@
 It supplied regulated -15V (10A), and +5V (16A, -A/-B; 22A -E/-F), and also i) a 60Hz signal for a [[line time clock]], and ii) ACLO and DCLO power status signals.
-It contained an input [[transformer]], and a [[printed circuit board|PCB]] which produced all the outputs. The actual [[power supply]] at both regulated [[voltage]]s was a [[switching power supply|switching supply]], for improved [[EI conversion]].
+It contained an input [[transformer]], and a [[printed circuit board|PCB]] which produced all the outputs. The actual [[power supply]] at both regulated [[voltage]]s was a [[switching power supply|switching supply]], for improved [[VI conversion]].
 The H720 was 8" high, 16-1/2" wide, and 6" deep, and weighed 30 lbs.
 [[Category: DEC Hardware]]