Dave's perpetual question thread

[Helevitia]

OK, I have some cooling questions. The motherboard will be in an area that is not fully closed in. The backside will be open but the other three sides will be closed. All other components will not be in the same area as the motherboard including the power supplies. So no other heat except the CPU, Video card, and any other card plugged into the motherboard. Other than the normal heatsink/fan, what should I be worried about?

Also, what about grounding? My motheboard isn't exactly going to be amongst the standard setup. How can I properly ground everything without a case?

Thanks!
Dave

[Wombat]

Grounding will be easy - it's the EMI you should worry about. Sounds like that will be your problem.

[Helevitia]

Why do I need to worry about EMI? What is going to cause EMI and to what components?

[Wombat]

That whole thing is going to cause EMI. All those clock generators and wires and....

And your system may not perform as well as it could. All those PCI bus lines and memory lines will just serve as antennae.

Appliances + unshielded electronics = hours of fun!

[Greebe]

My first choice would be to line the interior with copper foil, but if that's not available get some conductive nickel spray paint.

[Marshmallowman]

ahh...he finaly gets the perfect screw, only to find it's to noisy

[GNEP]

What about using tinfoil? Or is that just not conductive enough?

[Wombat]

Tinfoil isn't much for looks.

There's also some (kinda expensive) copper mesh that would let you see though the acrylic still.

[Helevitia]

Originally posted by Wombat
Tinfoil isn't much for looks.

There's also some (kinda expensive) copper mesh that would let you see though the acrylic still.

Let me clarify a few things. My mother board will not be in an acrylic enclosure. It will be surrounded by 3/4" particle board. Will the 3/4" particle board act as a shield? I will have one side with an acrylic window though. Should I close in the back as well?

Thanks for everyone's help, much appreciated!

Dave

[Helevitia]

Originally posted by Greebe
My first choice would be to line the interior with copper foil, but if that's not available get some conductive nickel spray paint.

Would aluminum tape work? You know, the stuff they use on heating/AC ducts? Gives me some more ideas

[Tjalfe]

Originally posted by Helevitia
It will be surrounded by 3/4" particle board. Will the 3/4" particle board act as a shield?
Dave

Only if you make it conductive with conductive paint, or line it with conductive foil

[Helevitia]

Originally posted by tjalfe
Only if you make it conductive with conductive paint, or line it with conductive foil

So how do normal cases work? What makes them conductive and act as a shield? What about aluminum cases? acrylic cases?

Thanks!

[Tjalfe]

aluminum is conductive, and will work fine as a shield, but acrylic cases... I don't think they will pass an emissions test.
The shielding is not as much for shielding the parts from emissions from the outside, as it is to keep it from sending out emissions to the outside.

[Helevitia]

OK, I've been thinking about all of this. I mean, how much do I really need to worry? People us acrylic cases all of the time and put acrylic windows in the case. I don't see webistes, forums posts, reviews, editorials, etc... of people having problems with this kind of scenario. What is the bottom line here?

[Tjalfe]

I don't think I would worry all that much, unless you start having problems with the computer interfearing with something around it, or the computer doing strange things when other electronic equipment is close.
If you were to mass produce and sell this design, you would have to worry about getting an EMC test, which would measure the amount of radiated power out of your case, but chances are you are not going this route, so don't worry