Hi all,

I have been looking for a new case to put a KM frontend into. I am planning to wall-mount our new Samsung LCD and wanted something small enough to fit into an opening in the wall just below the TV. Unfortunately nothing I have seen is as small as I would like (something about 12" wide or less, 12" deep or less, and 3 - 4" tall)

I have a lot of woodworking experience, so I was looking into building a case and laminating the front so the exposed portion is <whatever laminate/color we choose> but was concerned with the electronics portion, thus my question: Does a PC case contribute to the grounding of the PSU/components, or is that covered by the PSU itself? I have searched the 'net and found people building cases with plexiglass and other non-metallic substances, so I'm thinking wood (probably a 1/4" veneered plywood, if that matters) should be fine, but I thought I would post the query here to see what you folks thought about this.

If anyone knows of a reasonably priced case that fits the measurements noted above please do let me know. And if anyone can pass along some insight or links to the grounding/electronics issues of a non-metallic case it would be very much appreciated. The idea of building my case(s) to my specs very much interests me, but not if it would somehow decrease the longevity of the system, or end up burning the house down!

Thanks!

I don't know about grounding, but it definitely is a big part of the RF shielding. Without proper shielding PCs can interfer with all kinds of stuff like TVs, radios, audio equipment, cordless and mobile phones, ... basically anything electronic that is amplifying some kind of signal. Even if the device isn't intended to recieve RF broadcast signals (like a pure power amp or preamp) if may get them as noise through cables or power cords. So if you build a wooden case, definitely look into ways to provide that shielding. Possibly something like this... http://www.lessemf.com/paint.html

As always tjc, many thanks for the input.

Yowza! Those prices would certainly make me lean towards a "standard" PC case. I suppose I could line the interior with some type of lightweight metal, perhaps some of that galvanized sheet metal I have laying around from some duct work. I wonder if something as thin as aluminum foil would have the desired effect?

Thanks again for the information, looks like I've got some more research to do...

Yes. Foil or metal coated mylar or metal screening or anything 1) conductive and 2) grounded without too many largish openings will produce a Faraday cage which will provide RF isolation. This also helps to keep external RF noise out of your PC, especially the video and audio circuits where you're most likely to notice it.

BTW - I was thinking more of the spray can of "Super Shield for ~$25 which will coat ~11 sq ft. This is kind of coating you'll find on the inside of plastic PC cases.

And its really a good idea if you are gonna' have it near your Display.

I second tjc on the RF concerns. You would certainly want to provide some type of shielding.

RF shielding isn't the only reason PC cases are made of metal however. Metal is a good conductor of heat. You will need a lot better cooling with a case made of wood than a case made of metal. The combination of a tight small space and a wooden case may present some serious thermal issues.

Martian

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Vizio 37" LCD HDTV (1080p)

Perfect, this was the kind of information I was hoping for. Thanks

I spotted that after the initial "sticker shock" had subsided I will check around the local stores to see if they have anything lighter weight than the sheet metal I have. If not, I will look into the spray-on in that link.

You betcha! This is why I posted here, I knew there would be issues, I just didn't know what they were.

Thanks for the help, if I go down this road I'll be sure to update this thread.

Hi Martian,

Thanks for the input. At first I figured I would build a box without a top, so heat wouldn't be an issue at all. Now that the RF issue has come up it looks like that won't be feasible, but the box will reside in a closet with only the front panel exposed to the bedroom so I will be able to mount a number of quiet fans in it to exhaust the hot air and still not notice the noise.

This box will house an Asus M2NPV-VM with a Athlon 3200+, any small hard drive I can find lying around, and a DVD-ROM drive. I should be able to get enough airflow to keep everything nice and cool without it being very loud.

"War story" time...

At my first SW job, we were working with some early luggable "laptop" computers (no batteries as far as my memory goes). The problem was that neither the computers nor the monitors we were using with them were very well sheilded, and as a result the monitors kept bursting into flames because RF from the "laptops" was being picked up by the flyback transformers. Once we figured that out, one of the EEs made a quick trip to the grocery store for some aluminium foil, and using that, a paper clip, and some wire wrap wire for a grounding lead "solved" the problem.

Well, after rummaging around in the basement I came across an old "cube" case I had used to build a computer for my daughter when she first went to college. After doing some measuring it dawned on me that I could use this case almost as-is and simply make a faceplate to surround the DVD-ROM drive, power and reset switches and mount that flush to the wall (basically just pushing the drive and switches about 5" out the front of the case). Solves the RF/other electrical issues and allows me to make an even smaller hole than I had earlier anticipated. This is a good thing

Thanks again for all the tips/information, I'll let you all know how it works out.

Before the Inebriated in IRC party I was able to get my "homemade" case installed and working. Haven't named it yet, I'm leaning towards Knoppenstein right now (maybe FrankenMyth?)

Some pictures for the curious: http://www.tbf-investments.com/KM.html . Still needs some trim work, but it's pretty much finished (Please, no comments on the paint/trim. My wife's been after me about that for quite some time!)

For the not-so-curious I have the guts of the system in the closet with the DVD-ROM and power attached to a plate that is exposed to the room (through the wall).

1 question: Do I need to put the cover on the case or will the walls take care of the RF interference? Would the interference be noticeable immediately? I would like to leave the cover off to maximize cooling.

Thanks again for all the help...

Sorry about the pop-up folks, where the heck did that come from? Wasn't there when I tested it...

i wold love to see the case, but I cant seem to access the site.

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Really? I just accessed it from work, and checking my Apache logs it looks like quite a few others have too. Are you getting an error?

ah, i see the issue, the link redirects to a webserver on port 8590. My work wirewall want let me access http on any port other then 80. I'll just need to look at it from home.

Thanx

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R5F1 - Dell P4 2.4Ghz 500MB - PVR250 x 2 - GeForce FX 5200 - Onboard sound/NIC 80GB ATA/250GB ATA/400GB SATA