cctech Digest, Vol 87, Issue 3

Gregory Beat w9gb at
Sun Dec 5 13:45:21 CST 2021

Power Supplies, due to their Weight, are placed at the bottom of Racks (prevent tip overs — weight distribution).

The PDP-11/70 Maintenance and Installation Manual (EK-11070-MM-002) explains that the basic PDP-11/70 system components are located in a double cabinet as shown in Figure 1-1 of that manual.


> Date: Sat, 4 Dec 2021 19:28:01 -0800
> From: Marc Howard <cramcram at>
> To: "General Discussion: On-Topic Posts Only" <cctech at>
> Subject: Need picture of power supply mounted in 11/40 cabinet
> Hi,
> I've got an 11/40 I'm going to start working on.  Problem is that there are
> two power supplies (H742 and H7420) that came with it but neither was
> mounted in the rack.
> Could someone post/send/etc. photos of how the power supply mounts in the
> rack?  Also how is the power cabling routed (I think I'm missing this part)?
> Thanks,
> Marc Howard

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