Looking for two DEC H445 power bricks for PDP 11/40 project

Henk Gooijen henk.gooijen at hotmail.com
Tue Sep 18 10:45:52 CDT 2018

Hi Pierre,

Just to give you an idea, I will go to my museum either on Wednesday or on Saturday.

Till then,


Van: cctalk <cctalk-bounces at classiccmp.org> namens P Gebhardt via cctalk <cctalk at classiccmp.org>
Verzonden: Tuesday, September 18, 2018 10:11:43 AM
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: Re: Looking for two DEC H445 power bricks for PDP 11/40 project

>    > From: Henk Gooijen
>   > As far as I know, the 11/40 uses only one H745.
>Depends on what kind of memory it has. If MF11-L, it has two H745's; if
>MM11-U, it has an H745 and an H754.
>(The harness has two different connectors for the 5th 'brick', so it can
>handle either kind. At least, that's the situation on the later machines
>[serial numbers above 6000]; early production /40's only support the MF11-L,
>and you have to use special add-on harnesses to support an MF11-U in them;
>see DEC-11-H40SA-B-D, Chapter 6 for the details.)

As I don't have core memory modules available, I thought of using MS11 memory,
which, according to my research, seems to be an option for 11/40 systems.
The system manual states on page 6-7 that the base power configuration consists
of two H745 regulators and that one may be swapped with a H754 in case MF11-U
memory is used.
Does that mean that a single H745 regulator might be sufficient for my needs?

All the best,

More information about the cctech mailing list