Tool Review: DOMA Pro PCI Open Computer Case

Computers & Mobile Technology
Tool Review: DOMA Pro PCI Open Computer Case

I’m a minimalist by nature, which is what attracted me to this “no-case” from My Open PC in the first place. I have often toyed with the idea of designing something similar, myself—just a couple of panels with the bare-minimum cutouts to meet the ATX specification. While, over the long run, I think there are good reasons to keep a PC’s guts inside a hard case, in the short term, an open fixture like this has a lot to recommend it, for instance as a test bed for experimenting with different hardware configurations. I’ve built every desktop PC I’ve ever personally owned, and between that activity and the occasional component upgrade I seem to generate a fairly consistent trickle of surplus computer equipment. And every so often that trickle pools up to the point that I can cobble together an extra working PC. That kind of kit-bashing usually requires a lot of experimentation and part-swapping, which is where an open test fixture comes in really handy.

These are the two biggest parts in the box, the mainboard plate and the back panel.  The DOMA Pro consists of 16 total pieces of this 3/16″ CNC-milled translucent “smoke” black acrylic sheet, a case electronics package, and a box of metal hardware. There’s also a small acrylic wrench (which I did not use) for tightening the hexagonal coupling nuts used throughout assembly, a detailed parts list, and a page of instructions with nice clear isometric line drawings.

The metal hardware is very thoughtfully packaged in a six-compartment translucent polypropylene organizer with separate snapping, hinged lids. A printed label stuck to the back of the organizer identifies each bit by its name in the instructions, and there are at least one or two extras of each flavor. Such attention to detail seems characteristic of the product and its manufacturer, though they do make a couple of mis-steps, as I’ll discuss below.

The case electronics consist of two soft momentary push-button switches for power and reset functions, and one red and one green LED to indicate hard drive activity and system power, respectively, all of which come pre-wired with labelled sockets for your motherboard pins.

The fixture has space to mount one 5.25″ drive (probably an optical drive) and one or two 3.5″ drives slung under the mainboard plate. Assembly begins by screwing small one-size-fits-all acrylic side panels to your drives, which then interlock with the mainboard plate, riding underneath it where the drive side panels double as supports for the front edge of the case.

The drive assemblies are locked in place by a pair of small cams sliding on hexagonal coupling nuts secured to the mainboard plate. This trick—using cheap hex standoffs as bearing surfaces for moving parts—is one of a couple of examples of clever CNC-panel design the DOMA Pro includes. It’s repeated with only slight variation in the locking bar mechanism that secures the top corners of the PCI cards in place—much faster than screws, but more secure than just letting the cards sit loose in the slots.

Assembly to the stage shown here took me a leisurely hour, or thereabouts. I went on to add motherboard, video card, and power supply, and then to do a bunch of drive-swapping in the course of scratching together a Linux box for use with my garage CNC equipment. Then I transferred the working setup to a traditional hard case.

The only significant problem I had with the DOMA Pro, as it came from the manufacturer, was that it was wobblier than I like—Which is to say, wobblier than it had to be. Specifically, the bolted joints at the corners between mainboard and back panels were loose, which caused a bit of racking along the short horizontal dimension. Without having actually asked the designers about it, I’d guess the sloppy fit at these joints is caused by badly-specified hardware. The micrometer shows that the acrylic panels are very close to nominal 3/16″ thickness at 0.185″, while the coupling nuts that pass through them, which I bet are nominally 3/8″ (0.375″) are a bit long at 0.385″. I ended up shimming mine out with bits of tape between the two acrylic panels, and the problem went away.

The other small problem I had was with the female one-pin socket on the end of the positive leg of the system power LED. Specifically, it fell off after a single installation-removal cycle. Easily fixed, of course, but a bit annoying.

Overall, I really like this case both in theory and in practice. And considering its accessible price, it remains a good value in spite of the one or two small problems I had during assembly.

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

View more articles by Sean Michael Ragan


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