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Here is the back panel with motherboard and power supply installed. Weather-stripping foam decouples the PSU from the case to ensure minimal transfer of any fan vibrations.
The photo below shows the subassembly with the PSU just sitting on top of the motherboard. Cables were folded and rolled to to keep them out of the way. The fan in the PSU is almost directly over the CPU / heatsink, ensuring additional cooling.
Bottom Air Intake Vents
The photo below shows two rectangular holes directly beneath the drive assembly to ensure at least a small flow of air across the bottom of the hard drive. A thin, gauzy piece of cloth glued on the inside acts as a filter to catch dust; an occasional swipe with a vacuum cleaner should keep it clear. One of the three mounting screws securing the drive bay is visible in the center. Also visible are two of the five felt pad feet (one in the center) that provide about 3/16" clearance from the desk surface.
Completed Breadbox PC
The photo below shows the completed breadbox PC with the "hood" open. Silicone sealer was used around the cutout for the CD drive to help hold it in place. The top and bottom pieces of the breadbox were also glued together with silicone, which, BTW, take a full 24 hours to set. Once set, silicone glue's holding power is excellent, yet considerable dampening is provided by its rubbery resilience. Windows XP and all updates were installed on the system without a hitch.
In use, the system runs quietly enough that when working with it at the table shown below (with 19" monitor), it is almost inaudible, despite the very low noise level in the room, especially in the evening. The Seagate Barracuda IV single-platter drive and the slow-spinning fan in the Seasonic PSU make a very slight hum that is easily ignored. If there is any other noise in the quiet room, it becomes inaudible. Drive seek is slightly more audible, but still extremely quiet. Given the thinness of the plastic, the case might benefit from damping material such as an inside layer of Akasa damping mats or carpet underlay. When the system has proven to be stable for a week or longer, the plan is to seal the "hood" with silicone glue, which may provide a bit more noise reduction.
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POSTSCRIPT - September 30, 2002
Within hours after this article was published, there was discussion with readers via email and the forums about the lack of electromagnetic interference protectionion the Breadbox PC. Looking at this issue, all the components other than the motherboard are encased in steel, are already well shielded. Corrective suggestions included:
- Line the inside of the case panels with tar/aluminum panel dampening like Brown Bread. The down side is the mess and the loss of cool blue translucence. Nixed.
- A wire mesh screen cover for the motherboard. I happened to have some kicking around the garage, so this morning, I cut a rectangular piece as wide as the curved top surface and carefully wedged it in place, as shown in the photo below. The stiffness of the mesh holds it in place securely; it is not going anywhere even without any hot glue. And it does make contact with the PSU and CD-RW cover, so should be grounded. I believe this will do the trick. If anyone thinks otherwise, please email me.
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October 3/02 -- A final change was the addition of a grounding wire connecting the cases of the hard drive, CD drive and PSU to the wire mesh to increase its effectiveness against EMI.
Original Forum Discussion.
Reprise Forum Discussion, 2005.
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