custom wood case - questions

omega369 · Post by **omega369** » Mon Apr 30, 2007 9:43 pm

hey guys, just got an abit ab9 pro in the mail for really cheap, so i've decided to build a "silent" rig in a wood box.

i'm a mac guy, but i've built a pc before, and know what i'm doing-- plugging parts in with a store bought case. i have a few questions, however, about building my _own_ custom case. building it is no problem for me, and i'll be sure to post pics if it works out nice!

1)The motherboard has mounting points that are supposed to be used to 'prevent shorts'. does this mean i must mount it on metal standoffs and do they need to be attached to a metal plate? (like in a standard case) Will the potential life of the motherboard be compromised by mounting it on wood?

2)Can i buy a simple switch from radioshack to control the power on/off ?

3)Does a computer care if nothing is connected to the following headers: PWR LED, HDD LED, RESET, SYS LED, SPKR?

I want to make this pc as minimalist (visually) as possible, as far as unneccesary doodads and fancy 'elite led's' go, keeping with the mantras that apple designers follow... TIA

derekchinese · Post by **derekchinese** » Mon Apr 30, 2007 10:25 pm

From what I have seen, most people who build with wood will just take an old computer case and use strip it of the vital components like the power switch/reset switch, mobo standoffs. It should not be hard to find a cheap old case that you can use for your wood case. Trying build a wood case without parts from an older computer case is probably much more difficult.

Derek

merlyn · Post by **merlyn** » Mon Apr 30, 2007 10:42 pm

1) the 'prevent shorts' bit only applies to metal mb trays so no you don't need metal standoffs and life will not be compromised. due to the temperature that certain components reach however i would recommend creating a gap between the motherboard and the case, not to mention i think it's ugly otherwise. it is worth considering how you will handle the rear. will you use the i/o plate and what about add-in cards? remember that add-in cards tend to protrude below the motherboard at the rear.

2) yes, obviously not latching

3) no

recently done this myself, should be finished in a few weeks. i cheated quite a lot as my 733t carpentry skillz are appalling

still managed a htpc case that's quiet and cool enough, just has more room than necessary for storage. enjoyed the experience though, highly recommended. i learnt so much doing it i'm considering doing it all over again but better!

wussboy · Post by **wussboy** » Tue May 01, 2007 5:51 am

What about electromagnetic shielding? Is this even an issue for wood cases? I will build my next case out of wood, and I have considered gluing a layer of tinfoil to the inside of the case. Is it worth it, or should I save the tinfoil for a lovely hat to keep the RIAA from beaming anti-pirate ads into my dreams?

nici · Post by **nici** » Tue May 01, 2007 7:07 am

Well if i was to build a wooden case i would line it with tinfoil or aluminium tape, it wont hurt. No idea if it makes any differencce or not. maybe it stops aliens form probing your computer. Right now im too lazy to even have side or front panels on my P180 which is mutilated beyond recognition anyway.

IsaacKuo · Post by **IsaacKuo** » Tue May 01, 2007 8:08 am

omega369 wrote:1)The motherboard has mounting points that are supposed to be used to 'prevent shorts'. does this mean i must mount it on metal standoffs and do they need to be attached to a metal plate? (like in a standard case) Will the potential life of the motherboard be compromised by mounting it on wood?

You don't need a metal plate and I never bother. The life of the motherboard will NOT be compromised. Look at the back side of the motherboard...nothing but wires. It's the stuff on the other side which can generate heat. You can indirectly improve temperatures of those components a tiny bit by cooling the backside, because wires conduct a small amount of heat--but it's not worth the bother.

2)Can i buy a simple switch from radioshack to control the power on/off ?

Yes, but connecting the switch to the motherboard is nontrivial. The easiest thing is to rip a switch from an old computer. Even an ancient AT case with the old style of switch usually has a "reset" button which can be used.

The type of switch is important--you want a momentary switch that only closes the circuit when it's actually pressed.

3)Does a computer care if nothing is connected to the following headers: PWR LED, HDD LED, RESET, SYS LED, SPKR?

No. I hardly ever connect any of those.

And don't worry about metal foil or any other sort of RF shielding. I've never used it, and never missed it. Consider the popularity of cases with side windows--those let RF leak out just like empty space.

One little tip--expansion cards come with a backplane that pokes below the level of the motherboard. This is extremely annoying if your motherboard is resting horizontally on the bottom, or recessed for any reason. However, the solution is extremely simple--you can remove the backplanes from your expansion cards. All it takes is some needlenose pliers to unscrew standoffs, and in some cases a screwdriver to undo some bolts. Voila! No pokey bit!

Mr Evil · Post by **Mr Evil** » Tue May 01, 2007 8:24 am

wussboy wrote:What about electromagnetic shielding? Is this even an issue for wood cases? I will build my next case out of wood, and I have considered gluing a layer of tinfoil to the inside of the case. Is it worth it, or should I save the tinfoil for a lovely hat to keep the RIAA from beaming anti-pirate ads into my dreams?

The PC itself doesn't care much about shielding, but any equipment nearby* may be adversely affected if you don't shield it. aluminium foil ("tin" foil) works great, but note that it's hard to make an electrical connection to it due to the oxide that forms on the surface. Copper foil is better, but expensive. Conductive paints are available too.

If you do try to shield it, then it must be electrically continuous, i.e. all parts must be connected together with no gaps. Holes in the shielding compromise its effectiveness. Also make sure it's connected to earth (easy to accompish by connecting it to the PSU's case).

*PCs give off unholy amounts of EMI, so even your neighbours could count as being nearby. Audio equipment tends to be especially susceptible, with audible hiss and crackling on bad days.

omega369 · Post by **omega369** » Tue May 01, 2007 3:59 pm

thanks for the replies so far. what i'm still unclear on is: whether or not i need a metal contact on the motherboard mounts, as these are presumably additional grounding points for the board... escape routes if you will for electricity running where it shouldn't be.

IsaacKuo · Post by **IsaacKuo** » Tue May 01, 2007 4:24 pm

You do not need any. None of my scratchbuilt cases have any metal contact on motherboard mounts.

omega369 · Post by **omega369** » Tue May 01, 2007 4:40 pm

cheers. i'll be back around when i get it put together.

sareiodata · Post by **sareiodata** » Wed May 02, 2007 12:13 am

if one thing I can suggest from my experience building my wood case is WIRES ARE SHORT!!!. Plan carefully where your wires are suposed to be. The wires that power the computer from the power source are most troubling.

Good luck!

Palindroman · Post by **Palindroman** » Sat May 05, 2007 11:09 am

I'm also planning on trying my hand on a wood case. My main questions for now are similar to the ones in the OP.

1) Does anyone have any idea where I can buy a front panel with a power and reset button? USB and audio included would be even better. I have been looking for a while now but don't know which search words to use.

2) About the RF shielding: I plan on making an 'inner' case with 0.5 mm thick aluminum. Am I right in presuming there has to be a plate under the motherboard also? Does the metal under the lid actually have to touch the rest of the metal lining for the shielding to work? How about ventilation holes? I plan on making one large hole above the CPU fan and two smaller holes on the side for intake, and put some sort of grille in front of that.

Thanks.

jaganath · Post by **jaganath** » Sat May 05, 2007 11:30 am

1) you could pick up a cheap case on Ebay etc. and strip it for the front panel; not sure if it can be bought separately?

2) i don't think you need a plate under the motherboard

Does the metal under the lid actually have to touch the rest of the metal lining for the shielding to work?

i can't visualise this; the metal under which lid? like Mr Evil said, the shielding has to be electrically continuous for the shielding to work. The more and bigger holes you have in the shielding, the less effective it is, so try and put some closely-woven mesh over the CPU and intake holes.

ronrem · Post by **ronrem** » Sat May 05, 2007 5:10 pm

Around here the city dump/recycle gets a lot of old puters. You can often pick up a oldie for peanuts at a yard sale or thrift store---maybe even put up a few handbills. If you cut the mobo tray/back togather-that lines stuff up. You can salvage switches,HD cage/optical cage,floppy, whatever.

metal window screen makes a decent EMI sheild. you don't seem to need anything solid as perf or louvered metal appears to get used a lot in cases,PSU's. You do want some wire links so its all grounded.

I have a Stereo amp and a TV and a cordless phone within a few feet of this case---which has had it's sides off a few weeks. Seems to make no difference

ronrem · Post by **ronrem** » Sat May 05, 2007 5:16 pm

a little wire can connect all EMI sheild. The Electro and Magnetic parts of EMI will tend to get attracted to grounded steel,plain steel screen is good enough,cheap,easy to cut and shape. Also won't look as cheesy as tinfoil. You can spraypaint it so long as you maintain the link to ground.

Palindroman · Post by **Palindroman** » Sun May 06, 2007 1:39 am

jaganath wrote: i can't visualise this; the metal under which lid? like Mr Evil said, the shielding has to be electrically continuous for the shielding to work. The more and bigger holes you have in the shielding, the less effective it is, so try and put some closely-woven mesh over the CPU and intake holes.

Sorry about that. I'll be starting my own topic (hopefully) some time soon and post some pictures and drawings to show what I mean. The case will be 29 cm W x 29 cm D x app. 10 cm H. The panel on top will be a lid that can be lifted up somehow to open the case.

I did find some metal sheets with small 3-5 mm holes in them but wasn't too sure what that would do to ventilation. I'll go looking for mesh-like stuff.

I know I can take the switchpanels off an old computer but the thing is I want a relatively simple design that can be easily reproduced. A panel with a power switch, reset switch, 2 x USB and audio would be perfect. I did find a 3.5" panel by Silverstone with USB, Firewire and audio and I probably can find some buttons for power and reset, but it costs more than the wood, metal and paint combined. Where do case manufacturers buy these things?

jaganath · Post by **jaganath** » Sun May 06, 2007 1:49 am

I have a Stereo amp and a TV and a cordless phone within a few feet of this case---which has had it's sides off a few weeks. Seems to make no difference

On the other hand, I get terrible interference from my PC with the TV picture/sound, and this is with the case on and metal junk piled all around it

it may not help that the TV signal is quite weak in my area, but the disruptions in the TV picture/sound are definitely connected to what I am doing on the PC, if I do nothing the interruptions stop.

nici · Post by **nici** » Sun May 06, 2007 3:33 am

Case manufacturers buy them in huge numbers... but any momentary switch will work. You can spend anything from nothing to 30â‚¬ on one. I have a vandal proof machined aluminium piezo switch onmy case

EMI shielding is annoying me, copper tape is bloody expensive, so is conductive screening paint(also very hard to find), aluminium tape is difficult to get a closed loop with....

custom wood case - questions

custom wood case - questions

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