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I have a new motherboard which needs a BIOS update to support a new CPU.

Thankfully I have an old (compatible) CPU handy. My plan is to install the old CPU, update the BIOS, then install the new CPU.

I'd prefer not to have to mount the motherboard in a case just to do the BIOS update bit.

Is it safe to power up the motherboard outside of its case? My understanding is that the case provides grounding for the motherboard – could the lack of grounding be an issue?

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Some people even "glue" all their components to walls and let it run there :D –  DebugErr Jun 19 at 8:36
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Not only is it safe, assuming you follow the precautions listed in the answers below, it's in fact a good practice for new builds. Fully connecting all motherboard components outside the case and powering them on will quickly identify any components that might have been DOA. Once you've checked that the system boots, then you can install it into the case. –  Lilienthal Jun 19 at 11:47
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As everyone else has said, no worries other than the usual. I've done it 100's of times. I/Others have cases made of plastic that don't provide grounding. Even then, metal cases are never grounded to anything. –  user1596244 Jun 20 at 11:51
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as @user1596244 said, metal cases are not grounded. The grounding of the Motherboard is provided by the PSU, which is of course grounded to the power grid. –  iFreilicht Jun 20 at 12:21
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Make sure to mount a cooling system even on your temporary CPU, otherwise it would become too hot very fast. –  Double Gras Jun 20 at 22:22

13 Answers 13

up vote 62 down vote accepted

Yes, it should be safe. Just be sure to put your motherboard on something not conductive, like cardboard box, and it should not touch anything that conducts electricity, including your main computer case. I did this few times. If you stop by in almost any computer shop, technicians do this sort of thing routinely.

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Also, it is a bit harder to keep track of all wiring that runs around the MB when it is not in the case. So make sure none of the wires/cables get caught in the cooler fan. –  smc Jun 19 at 10:56
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Back in my day, they used to sell open racks (not enclosures) for mounting components, so everything was out in the open. This was handy for learning how PCs work, troubleshooting a suspect component, etc. Sometimes, these racks weren't even metal. –  Patrick S. Jun 19 at 12:50
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I learned quickly when I was starting out with assembling computers that they didn't need the case, and when building myself new pcs, I'd not order a case just to bring down the price, my room was a bunch of boards strewn around and connected all over the place for a decade. –  stephenbayer Jun 19 at 20:11
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And don't drop any screws on it while it's running! –  romkyns Jun 20 at 13:36
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For the cardboard box, you can use the motherboard box itself -- it is sized perfectly. –  Reid Jun 20 at 16:34

Yes, you can power on the motherboard outside of its case. Just keep some precautions, like laying a piece of cardboard underneath the board, and you're good to go.

Also, human body contains static charge, so ground the static by touching a grounded appliance or wiring a ground circuit. Static charge in the human body might damage sensitive electronic components of the motherboard.

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I'm not sure how helpful "touching a grounded appliance" is for people wondering about this. "Touch a radiator" may be easier to explain ;) –  Voo Jun 19 at 9:44
    
Or the groundpin in your electrical socket (if present, in Europe it is) –  Martijn Jun 19 at 10:28
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Note that antistatic bags are specifically designed to be conductive. While they may be useful at preventing a static charge from building up and damaging an unpowered device, they also happen to be decent at shorting contacts of a powered device, thus potentially causing damage (though unlikely). Therefore, you really shouldn't be powering up any device while they are in or on an antistatic bag. –  Bob Jun 19 at 10:45
    
@Bob: Point noted. Thanks. –  Ricky Jun 19 at 10:54
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@Chris It's usually not overly dangerous, since the conductivity just has to be enough to prevent the buildup of a massive voltage for a static shock (therefore, unlikely enough to conduct the max of 12V for a motherboard). The problem is you can get cheap/crappy bags that are more conductive than they should be. Also, this means it's strictly worse than a plain insulator - so while a warning against it isn't really necessary, it's also not good to recommend for it. –  Bob Jun 19 at 14:43

The other answers you got are correct: it's definitely doable and something that is done all the time by professional/power/enthusiast users for all sorts of purposes.

What I would like to add is that, if you search online, you'll see that a lot of people will turn the motherboard ON using a screwdriver: they simply close the circuit between the 2 power pins using the metal part of the screwdriver. This is done because you no longer have a power button (since there is no case). The electrical current in there is extremely small, so there's zero chance of harm.

However, be very very careful if you use this technique. Touching the wrong pins can damage the motherboard. They usually have some protections in there for situations where people don't connect the cables properly, but you shouldn't rely on this.

To mitigate these risks, there are 3 possible solutions:

  • be super super careful when you do it
  • get the power button out of your case and connect it normally. It should work. It's a simple circuit-breaker
  • some motherboards (more expensive ones, dedicated to high-end PCs) have a power button on them. If yours does too, use that instead.
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Some motherboard vendors (notably Asus) provide internal power-on button –  mvp Jun 24 at 3:30

One thing to watch out for is add-in cards coming loose. On some cards, the rear connector bracket is long enough that it hangs below the bottom of the motherboard when the card is plugged in to the motherboard. This isn't a problem in a case when the motherboard is mounted on standoffs, but it can be a problem if you sit the motherboard directly on a hard flat surface - the weight of the motherboard can pull it away from the card, like so:

Diagram of potential issue

You may need to elevate the motherboard half an inch or so to prevent this.

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you waste your electrical shielding and get maybe some weird effect in nearby radios, or whatever transmitter - or in case you have strong senders nearby (maybe lay your nice smartphone on the motherboard) you induct some current somewhere on the motherboard, and if its an good one (means on the technological edge) there will be less room for errorcorrection of these ... also every wifi- bluetooth connection will be disturbed (at least a little) with this extra RF noise around. or in other words, you have to pay extra attention to the said shortcutting, dirt and dust probllem, maybe to water (in the air or simply your coke bruzzling around) AND the over the air electrical (non)shielding

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Valid point about EMI here. However, you have to remember the fact that MBs are designed with enough shielding and MB manufacturers do not rely on computer outer casing as a main shielding for EMI noise. In fact, outer case is often made of plastic, so taking MB out, does not change the overall picture. –  smc Jun 19 at 13:09

The case provides a number of benefits:

  • physical protection.
  • airflow management.

Generally, some electronic devices on PCBs operated outside the designed casing can end up running hotter.

This probably isn't an issue for short periods of use.

enter image description here
Example of desktop PC with fan in case (at top of photo)

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Sounds strange. There should be much more air accessible around when no case is present, why would any devices become hotter? –  Ruslan Jun 20 at 10:49
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@Ruslan, in a case, there's a case-fan which actively pushes air across the motherboard. Although the CPU and PSU have their own fans, other components rely on a flow of air passing over the motherboard. This is an important part of the thermal design of many products. Without that active management of airflow you are reliant on convective movement of air only, this may be insufficient under some circumstances. –  RedGrittyBrick Jun 20 at 11:08
    
@RedGrittyBrick Never seen a case with its own fan. –  kinokijuf Jun 20 at 11:14
    
@kinokijuf first case I checked has two fans: photo. –  Ruslan Jun 20 at 11:21
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@kinokijuf: I just opened up a desktop PC, took a photo and added it to my answer. They may be more common on servers but they can still be found in desktop PCs and notebooks too. Even if your PC relies in the PSU fan, that depends on the enclosure to ensure air is drawn across other components, without the enclosure, the airflow into the PSU comes from the room and not so much from across the motherboard. –  RedGrittyBrick Jun 20 at 11:25

Strictly no, in practice definitely yes: yes you can power up the motherboard outside of its case, or just forget the case altogether and harvest the power supply. You can happily run such a system with all of your components on the desk/shelf/whatever, great way to have an "extra" PC around in plain site that doesn't look like your typical PC.

But to explain the strictly no, having exposed components around makes it easier to short some circuits, or just get dirty faster, or collect spilled coffee etc... You probably don't want to drill some holes in metal over the motherboard, little metal filings going everywhere won't be good for that. Once you get used to having the mobo in the open, you tend to not notice these little mistakes until its too late.

The power supply connection(s) provide the ground to the mobo, not the case. The case just happens to physically touch the power supply's case, which is grounded, and thus the case gets ground as well.

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If the motherboard is screwed into the case, it does connect its ground to the case — even if you keep PSU outside the case. That's what the soldered lands around the motherboard holes do. –  Ruslan Jun 20 at 11:33
    
@Ruslan Yes the motherboard has a grounding connection around each of the screw holes, you're right about the circular solder leads. However those are "optional" grounding connections, the "main source" of ground must come from the PSU itself, some of the cables provide this. Grounding the main case and the PSU case is an extra safety feature. Having the motherboard out in the open loses that extra safety feature. –  Chris O Jun 20 at 12:29
    
It seems like there are kinda two meanings for "ground". In an electronic circuit, your normal "ground" pin is often a local ground...just a voltage sink, electron pool, or what have you...and basically everything uses it. The case, on the other hand, provides a "chassis ground", an honest-to-goodness ground that connects to the third blade/pin on your power cord (though it probably does this indirectly through the power supply's own chassis ground). –  cHao Jun 21 at 22:31

Keep in mind that many of the locations for screws on a motherboard are ground points. The screw grounds to the case and the power supply to the walls ground.

I'm sure it will run without them grounded to the case but I'm also sure your board is safer well grounded.

Ever wonder why there is copper/gold around the screw locations on the motherboard?

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This is a good point and noted. Seems the consensus on the net is that the power cables and other connections (monitor, USB) will provide sufficient grounding. Searching the net I also found Asus sold (perhaps still does) motherboards in a box that doubles as a temporary case - that gives me some assurance that generally motherboards should be OK without screw sockets grounded. –  misha256 Jun 20 at 8:13

Inside a lab probably yes even if is a custom lab.

IF you make a safe place to work without any cable or power interrumption . you are talking about a BIOS upgrade, not a common software fail safe after format.

you can't say something is 100% safe for it, when was not been builded for it.

where will you place it?

on a carpet? you can burn it

on the floor? you can crash it

People may transit around and think is a shiny toy

Its case will provide many things

  1. Hit protecion
  2. Garbage protection
  3. Anti-static protection
  4. Pins will not touch any thing but the air
  5. Grounding .

And yes. you can't mount it outside it case. not a good practice.. more like a gamer practice.

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Something that has not been answered in previous answers:

The power supply will provide grounding for your motherboard. This means that, if you plug your power supply in a grounded wall socket, then automatically the components attached to the power supply are more or less grounded.

However, your computer case is not automatically grounded; the screws on your motherboard may not necessarily be connected to your motherboard's ground. Most commonly, the computer case is grounded by simply screwing in the power supply, since the case of your power supply is grounded.

So, yes, it is 'safe' to run your motherboard outside of a computer case (if you do not own a cat), but it is not 'safe' (from a grounding perspective) to run your power supply outside of the computer case.

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Yes, but less.

(Prevent shorts, prevent electromagnetic discharge, prevent strong magnetic fields, try not to get it dirty, that's all)

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As long you don't do it on a metal surface or put some material at the bottom which can cause short circuit its not a problem.I remember setting up my computer when I was 9 years old all of the computer parts were out of the case.They were all over the bed.Use bed if you are doing it on your bedroom.Its soft and there is no way for it pass the electricity but be aware it can get really dirty :D

Also remember in order to start the computer you need to short circuit the pins on the motherboard by yourself cause probably the switch cable of the case will come to short to attach on it.Be careful while doing that a wrong short-circuit can cause you trouble.

But of course its still best to put in into case.Dont use your pc like that just test whatever you want and put it back in.

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pic

In the above image there are 3 different types of "grounds" (3 different symbols) and they are not connected to each other:

  • ground of the case (power supply) connected to the "ground" wire on the wall outlet
  • ground on high-voltage DC side (looks like triangle)
  • ground on low voltage DC side (look next to each DC output - capacitor is connected there)

So, motherboard is NOT "grounded" by power supply: it is NOT connected to the "Ground" wire (NOT connected to the "ground" on the wall outlet). It is connected to it's own "low-DC-side" ground which is isolated from the outside world.

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Interesting research! But are you sure about this? The power supply itself is encased in metal and this casing is grounded to earth. Installing the power supply into a metal PC case will extend grounding to the case too. Then, installing the motherboard onto the brass stand-offs inside the PC case will extend grounding to the motherboard too. Am I mistaken? :-) M –  misha256 Jun 23 at 3:22
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One more thought: if a motherboard's ground was isolated from the outside world, wouldn't that cause all sorts of issues when we connect external peripherals to the motherboard like Monitors, TVs, powered USB devices... I'm thinking nasty ground-loops and like? –  misha256 Jun 23 at 3:50

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