Mouse Pissed! Need power supply help

Allison ajp166 at
Wed Nov 23 13:51:53 CST 2005

>Subject: RE: Mouse Pissed! Need power supply help
>   From: "Julian Wolfe" <fireflyst at>
>   Date: Wed, 23 Nov 2005 13:18:02 -0600
>     To: "'General Discussion: On-Topic and Off-Topic Posts'"	<cctalk at>
>Interesting, I was never aware that the 11/03 and 23 had different boxen
>than the 11/23plus, though I knew the power supplies were different.
>Speaking to my local DEC salvage dealer, he told me he used to get whole
>11/780s just for the power supplies in the front end 11/03s.  However,
>judging from the number of 23plus systems that were sold (and have recently
>hit, if not flooded, the used market)I'd say it should be fairly easy to
>find a cheap H7861 supply.

There were four major boxes used, and a few oddballs as well.

The majors were:
BA11-m with the H780 on the side. smaller cage.
BA11-N H786 in the front 
BA11-S H7861 in the front

A good PC power supply will do the DC needs of a modest system
but the signals BDCok, BPok, Bhalt, Bevent (ltc), Srun need 
to be created.


>> -----Original Message-----
>> From: cctalk-bounces at [mailto:cctalk-bounces at]
>> On Behalf Of Pete Turnbull
>> Sent: Wednesday, November 23, 2005 11:52 AM
>> To: General Discussion: On-Topic and Off-Topic Posts
>> Subject: Re: Mouse Pissed! Need power supply help
>> On Nov 23 2005, 10:51, Charles wrote:
>> > I've found the reason why my PDP-11 power supply (H7861) is not
>> > putting out POK and DCOK signals.
>> [ ... ]
>> > Unfortunately the H780 schematic does not match closely (they use
>> > 74123's while this one uses 555's, for example) so it'll be hard
>> > to figure out the missing or unreadable parts anyway!
>> The H7861 is a reworked version of the H786 design, which is fairly
>> different from the H780.  The H786 is used in the BA11-N box commonly
>> used for PDP-11/03 and 11/23 systems, and the H7861 is used in the
>> BA11-S box commonly used for 11/23plus and 11/73S systems, so you
>> should be able to find the schemeatics amongst the BA11-{N,S} drawings.
>> --
>> Pete						Peter Turnbull
>> 						Network Manager
>> 						University of York

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