> to keep EMI out of your motherboard and so forth.
It's the other way around: to keep the EMI inside. To not disturb aircraft radio and so on.
Actually it's a two way consideration but it's primarily to keep away outside EMI.
The wires in your wall right behind the PC act like huge antennas for it.
If you ever have a motherboard outputting enough EMI to affect aircraft you'd better be wearing a tin foil hat while you use it.
Probably also need EMI shields for your hard drives so you don't wipe or corrupt them.
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Last edited by PCBONEZ on 2016-01-18, 19:52. Edited 1 time in total.
GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
Aluminium foil was my idea, but that's just not stiff nor strong enough to stay on it's place, so I was thinking cardboard with aluminium foil wrapped around it...something like that.
That would work.
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In the past I have used aluminum flashing material (the kind used in roofing) which is thicker than foil but not so thick it's hard to use.
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I've also glued aluminum screen (window screen) to card board leaving the contact area (to the case) unglued for electrical connection.
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Personally I don't think it's as big a deal as the industry does, at least not around here, I'm just telling why the industry does what they do.
I might have a different opinion if I still lived near military radar or an airport.
The industry has to make it work for everyone in every situation (not just me or you) so they use metal I/O shields.
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GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
PCBONEZ wrote:Actually it's a two way consideration but it's primarily to keep away outside EMI.
The wires in your wall right behind the PC ac […] Show full quote
h-a-l-9000 wrote:
> to keep EMI out of your motherboard and so forth.
It's the other way around: to keep the EMI inside. To not disturb aircraft radio and so on.
Actually it's a two way consideration but it's primarily to keep away outside EMI.
The wires in your wall right behind the PC act like huge antennas for it.
If you ever have a motherboard outputting enough EMI to affect aircraft you'd better be wearing a tin foil hat while you use it.
Probably also need EMI shields for your hard drives so you don't wipe them.
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Here it can happen that the 'Bundesnetzagentur' visits you at home when your radio clock interfers with critical services such as aircraft radio - and if a radio clock can do it it shouldn't be hard for a computer.
PCBONEZ wrote:Actually it's a two way consideration but it's primarily to keep away outside EMI.
The wires in your wall right behind the PC ac […] Show full quote
h-a-l-9000 wrote:
> to keep EMI out of your motherboard and so forth.
It's the other way around: to keep the EMI inside. To not disturb aircraft radio and so on.
Actually it's a two way consideration but it's primarily to keep away outside EMI.
The wires in your wall right behind the PC act like huge antennas for it.
If you ever have a motherboard outputting enough EMI to affect aircraft you'd better be wearing a tin foil hat while you use it.
Probably also need EMI shields for your hard drives so you don't wipe them.
.
Here it can happen that the 'Bundesnetzagentur' visits you at home when your radio clock interfers with critical services such as aircraft radio - and if a radio clock can do it it shouldn't be hard for a computer.
No going to happen.
If a PC were to emit that many watts of EMI it would kill ITSELF so no more problem.
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GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
You should read up on the topic before making more false statements...
I've been a CET (Certified Electronics Tech) for 34 years so I've been reading about it for 34+ years.
- And I don't get my information from 3rd rate News media.
What you suggest is blatantly ignorant.
GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
I'm not sure about EMI. Come on, the front of the case is made of plastic! And there are cases made almost entirely of plastic (laptops, desktop AcerMate series).
For what I know, one of the purposes of I/O shield is I/O ports grounding. Remember the story with i865 south bridge burning all the time on low-quality cases, when people inserted flash drives into non-grounded fron panel USB ports?
Take a look at the small fins, they make sure the connector encasing is always on ground level:
An I/O shield will not provide a reliable, low impedance path for DC or low frequency current. It's much better design for jacks to bond through dedicated pins or physical mounting studs.
An interesting story a prof once told me. They had some kind of smart terminal in a corner office whose local oscillator interfered with equipment in cop cars as they drove by (radios or radar guns, not sure which). They got a visit from the boys in blue and had to figure out some kind of shielding for it. As for a PC interfering with aircraft systems, unless you're dinking around with it in the cabin, I doubt it's a huge concern. Aircraft have to contend with far nastier stuff both from internal avionics and radio and radar systems typical for modern airports.
are atx/at cases only have seven slots? Also where can I get a AT power switch for the atx to at converter
ATX only has 7 slots while AT can have either 7 or 8. If using an ATX case it is no big deal, you just can not use the 8th slot. (or you could without a backplate if it is just an internal device, like a hard drive controller or something) and there is a seller on ebay that sells the adapters, otherwise you can look around the forums for guides on how to make your own.
An I/O shield will not provide a reliable, low impedance path for DC or low frequency current. It's much better design for jacks to bond through dedicated pins or physical mounting studs.
EMI from outside sources is typically RF.
gdjacobs wrote:
An interesting story a prof once told me. They had some kind of smart terminal in a corner office whose local oscillator interfered with equipment in cop cars as they drove by (radios or radar guns, not sure which). They got a visit from the boys in blue and had to figure out some kind of shielding for it. As for a PC interfering with aircraft systems, unless you're dinking around with it in the cabin, I doubt it's a huge concern. Aircraft have to contend with far nastier stuff both from internal avionics and radio and radar systems typical for modern airports.
That sounds like a PSU with a bad (or crap) input stage filter sending switching noise back out into the wiring which then acted as an antenna. I might believe that could affect a radio if it were close enough. Hitting a car at a hundred feet or so takes a lot less power than hitting a plane several thousand feet away. And you are right. Equipment in planes is shielded against it.
Even radio stations don't output enough power to affect planes.
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GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
I'm not sure about EMI. Come on, the front of the case is made of plastic! And there are cases made almost entirely of plastic (laptops, desktop AcerMate series).
Laptops have shields over the component areas. Usually a whole network of shields.
Also on the backside of the keyboard. Is not the keyboard that needs that to be metal.
Cases come with steel panels behind the plastic and knock-outs for the bays. Those knockouts are -supposed- to be put back if you vacate a bay.
Some companies used to make them easy to put back in but so few people know enough to do it they quit making them that way to save $.
Even today companies that sell servers offer metal blanks to put in unused bays. High end case companies may also.
Acer certainly does use shielding on their laptops.
Desktop AcerMate, I dunno. Never had one.
I have had or worked on similar vintage & style of other brands and they all had metal panels behind the plastics.
(Off the top of my tin foiled head: HP, PB, Zenith, Gateway, IBM.)
All the consumer cases of the time I recall (and now for that matter) had metal panels behind the plastics.
Acer may have been playing cheap-down games with this series.
RacoonRider wrote:
For what I know, one of the purposes of I/O shield is I/O ports grounding.
Port shields (meaning those shields that don't come off the board) are well grounded to the motherboard already.
That is not the case with front ports. Especially cheap ones.
I think the tabs are to prevent the case and motherboard from being at different ground potentials due to an otherwise long path.
Wouldn't be needed if the mobo is properly grounded to the case but not all of them are so the industry assumes they aren't.
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GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
new issue: I recently got the ga586hx. when I put in the mmx 233 in all I get is continuous short beeps. I then took it out and put in a 200 non mmx in and gave me the ram error(this is due of not getting two edo sticks in pair so I found out so non issue as of now) I thinking its problem outdated bios. I am aware that the short beep is "power supply failure" I tested these power supplies in a another board and there fine, but really be that?
new issue: I recently got the ga586hx. when I put in the mmx 233 in all I get is continuous short beeps. I then took it out and put in a 200 non mmx in and gave me the ram error(this is due of not getting two edo sticks in pair so I found out so non issue as of now) I thinking its problem outdated bios. I am aware that the short beep is "power supply failure" I tested these power supplies in a another board and there fine, but really be that?
I am not aware of an Award beep code for PSU.
- That doesn't mean there isn't one because some manufacturers add additional codes to the standard set.
As standard, Award @ continuous short beeps = memory error
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GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
been a little while. the good news is now the board does post but found bios is at 2.5. also I tried to but a USB connector near the at keyboard connector and noticed it smoking near the at keyboard. board will still post however. I tried to use a USB card but it doesn't let me use keyboard. if only the USB header is gone no loss but I am concerned that the at keyboard port might be gone.
been a little while. the good news is now the board does post but found bios is at 2.5. also I tried to but a USB connector near the at keyboard connector and noticed it smoking near the at keyboard. board will still post however. I tried to use a USB card but it doesn't let me use keyboard. if only the USB header is gone no loss but I am concerned that the at keyboard port might be gone.
It smoked at the keyboard or at the keyboard port?
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You added a USB port?
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GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
NEVER plug a connector in a header in a Socket 7 (or older) board without triple-checking the pinout. There were no standards for those, and odds are you shorted the ground or VCC with something. Hopefully you didn't fry anything important.
Do AT keyboards still work or are you trying to use an USB keyboard? Most Socket 7 boards did not feature legacy support for USB keyboards, so they won't work before Windows loads (and even then, only after the drivers are installed).
also I tried to [put] a USB connector near the at keyboard connector and noticed it smoking near the at keyboard
That's not a USB connector, it's for connecting to those cases that have an AT keyboard connector on the front. Probably by connecting a USB cable to it you ended up causing a short circuit, resulting in the smoking.
If the keyboard connector still works after this, consider yourself very lucky!
