DEC top-mount corporate cabinet

Chris: The traditional DEC racks/cabinets are either full-height ("standard" = H960) and part-height ("short" = H967) 19" racks. These are welded steel frames built for computer-room type environments. When DEC started selling into office environments (think data processing / business operations) they designed a new line of cabinetry that was intended to fit into an office where sight-lines are important and the desire was to look/work more like other types of office equipment. The PDP-11/60 was I think an early example of the redesigned cabinets -- really a double-wide plus a bit, but of more modest height (roughly that of the H967). After that you see single-width cabinets holding just 18U like the one that you have -- capable of holding a complete, but modest, system. These newer-style cabinets/racks are riveted, rather than welded. Emphasis was on style, cost-effectiveness, and RF shielding given the need to operate near other types of office equipment. Here's a good overview: http://vtda.org/docs/computing/DEC/Catalogs/EA21388-75_CabinetAccessoriesSup pliesCatalog1981.pdf On the left side of page 8-of-16 you'll see a description of the 40" Medium Systems Series, including diagrams and pictures of the "top-loader" (H9642-AD) and "front-loader" (H9642-CA) designs. There isn't any "mod-kit" to go from one to the other. It would be possible to get a functional top-loader out of a front-loader with some metal reworking. Basically, remove the lid and then (in effect) move the cross-pieces down 6U and add what amount to four gusset plates for lateral bracing. In the H9642-AD photo you can see the plates on the rear cross-piece. The front is similar, but sensitive to ensuring that the center 6U isn't significantly occluded; the front cross-piece may require some modification. There are a few other changes but moving the cross-pieces down are the key. Notice the H9544 CA Trim Kit, RL01/RL02 -- these are plastic pieces that bridge the gap between the HDD cover and the cabinet side-panels; nice to have but they're mostly there for style. If you decide to attempt (or simply want to gauge the complexity of) a conversion I can see about getting some close-up photos of the various components and connections. A conversion would not be a simple task. While the brochure speaks of "purchase as component kits" and the table simply states "Basic Frame Kit", it's not the *same* frame kit for -AD and -CA, and I suspect that "kit" in this case was not an IKEA flat-box of parts but rather a factory-assembled frame to which one added other components as appropriate for the intended use. These frames are _seriously_ riveted. Notice that H9542-AD is distinct from the H9542-CA "component kit". (Note that the TU80 -- http://gunkies.org/w/images/5/52/Tu80.jpg -- is basically a H9642-AD "top-loader" with a hinged lid and special-purpose 13U front.) -----Original Message----- From: Chris Elmquist <chrise at pobox.com> Sent: Monday, February 28, 2022 2:08 PM To: pbirkel at gmail.com; General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Subject: DEC top-mount corporate cabinet On Saturday (02/26/2022 at 03:21PM -0500), pbirkel--- via cctalk wrote: has). Is there a (hand-)book that describes the DEC cabinets and in particular this "top-mount corporate cabinet"? Is there a BA # for this cabinet? I have an 11/34 in said cabinet but it is missing this 1U strengthener although I do have the 1U front-bar. I had to jigger a means to hold the front-bar in place and have been unable to understand how it would correctly attach to the rack and the strengthener, probably because I don't have the strengthener! Any part numbers or drawings that show this arrangement would be quite helpful. Thanks! Chris -- Chris Elmquist