Plug in 4 Pin and all other power fails. Why?

November 7, 2011 at 07:55:16
Specs: W7, AMD 1.9 x4 - 6GB DDR3
I have a desktop, when I plug in the 4 Pin Connector, Nothing gets powered and wont turn on by any form. If everything else is plugged in and not the 4 Pin. Everything Turns on, Obviously no |Post because no CPU power.

See More: Plug in 4 Pin and all other power fails. Why?

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#1
November 7, 2011 at 08:04:52
Probably because you are overloading the power supply and it is giving up.

Stuart


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#2
November 7, 2011 at 08:25:17
I can't see why it would be over loaded. I tried unhooking all. and just mobo and CPU, its same thing.
It also Worked before for a while. Been pretty much same thing for 2 years. Exception of new ram and Graphics card but still worked.

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#3
November 7, 2011 at 08:35:05
Post the brand and model number off the power supply.

Are you connecting that 4 pin connector while the power cord is plugged in?


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Related Solutions

#4
November 7, 2011 at 10:08:24
Power Supply: XFX: XXX Edition - XPS-650W-3XS

I Normally Flick The Power Switch


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#5
November 7, 2011 at 11:10:56
That PSU should be able to power anything you have connected.

I suggest you boot into the BIOS screens and check the three main voltage readings. The numbers should read within +- 5% of the rated voltages.

If you have installed a different Graphic card, do you have the required power connectors plugged into it?

If this has been an ongoing issue, I also suggest you check the polarity of the wall receptacle.


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#6
November 7, 2011 at 11:31:13
I Cannot Go into bios.
Cpu Does nothing if powered.

This happened over night. First time problem. Im sure its not a power supply problem. I have recently attempted to power only mobo and CPU with 400W and still nothing. I think its a mobo or CPU problem but thats me.


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#7
November 7, 2011 at 16:08:59
When did you change the graphics card & RAM? Did the computer boot after that?

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#8
November 7, 2011 at 16:42:54
I have not changed it since it broke but i have taken them out to try it.

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#9
November 7, 2011 at 18:06:37
"Exception of new ram and Graphics card but still worked."

Which graphics card ?

Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.

If you're a gamer...
In most if not all cases, the max capacity rating of the PS is an intermittent rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should have.

"Power Supply: XFX: XXX Edition - XPS-650W-3XS"

That may not have enough capacity, depending on which video chipset is on the video card, or it may have been defective.

Power supplies that don't have enough capacity for when the video chipset on the card is installed often work fine when you first install the card, but the power supply is being overloaded and it WILL be damaged, sooner or later.

" I have recently attempted to power only mobo and CPU with 400W and still nothing."

If the video chipset on the card requires a minimum of a lot more than 400 watts, the computer probably will not boot when the card is installed.

Try your "XFX: XXX Edition - XPS-650W-3XS" with the computer you got the 400 watt power supply from, or with whatever working computer. If it doesn't work with that computer, either you have damaged it or it's defective.

E.g.
My brother had a high quality Antec model that had a defective controller chip. If you placed a small additional load on the power supply, in his case when he tried to burn a CD, it black screened and rebooted the computer.
I have an old K6-III 400 system that also has a defective controller chip - it's average quality power supply shuts off the mboard when you plug an external drive into a USB port (it draws 500ma @ +5v - 2.5 watts) !



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#10
November 8, 2011 at 06:38:32
I've determined that the Mobo has a bad Female 4 Pin and I'm going to call Asus and Have mobo Replaced. Ill let you guys know if it Works.

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#11
November 8, 2011 at 06:58:11
It would be more likely the power connector is bad. Dis you check the output on it? See the link below.

http://pinouts.ru/Power/atx12v_pino...


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#12
November 8, 2011 at 07:03:31
It's a lot more likely your problem is with your power supply.
Try it with another working computer if you can !

If you do that and find your PS works fine, it's a lot more likely you damaged the mboard by doing something you should not have done than the mboard is defective. E.g. You MUST remove the live AC power to the power supply at ALL times when you're fiddling with connections or components inside the case, otherwise you can easily damage the motherboard or the power supply or both.
The Asus warranty does not cover damage caused by you doing that.

Which 4 pin connection on the mboard or wherever are you having this problem with ?

Which graphics card are you using ?

"Cpu Does nothing if powered"

The term CPU is frequently mis-used .
The computer case and the components inside of it IS NOT A CPU !


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#13
November 8, 2011 at 14:17:44
I have tryed other PS on same motherboard, And it continues to not work. I doubt both have same problem. The Machine Died while I was sleeping, No change as per exspansion cards or anything else within 1 month. Only difference I did was put my tower on my desk instead of the floor.

the problem is with the 4Pin Connector on the Mobo to power the CPU. Using a
nvidia geforce gtx 550 ti for graphics.


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#14
November 8, 2011 at 14:41:45
The system will not run without that 4 pin connection.

Strip the system down to the bare essentials. PSU, MBoard, CPU w/HS/fan, 1 stick of RAM, graphics of some sort, monitor Keyboard.

Verify the CPU fan is spinning up. You should get 2 beeps with that configuration. Try re-seating all connections and RAM.

The motherboard may well be defective but your logic as to why is faulty.


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#15
November 8, 2011 at 16:24:25
"I have tryed other PS on same motherboard, And it continues to not work. "

That doesn't necessarily prove the mboard is the culprit !

See response 12 !

"Using a nvidia geforce gtx 550 ti for graphics."

Minimum power supply:

400 watt or greater with a minimum of 24 amps on the +12 volt rail

Some power supplies have more than one amperage rating at +12 v because they have more than one +12 v section on the PSs board - if so, add them.

If the 400 watt PS you used doesn't have at least that total amperage at +12 v,
or even if it does if it's an el-cheapo PS that rating may be a lie
- in that case your mboard would probably NOT BOOT when that video card is installed, even when there is nothing else wrong !

Try your 650 watt PS with a working computer !
............

"The Machine Died while I was sleeping,"

If it was running, WHY was it running while you were sleeping ?

If it was not running, you did NOT need to have live AC power going to it.

It's possible there was a power failure event while you were sleeping.
That can produce power surges or voltage spikes that can damaged the computer or anything attached to it, especially if it was caused by lightning strikes.

"No change as per expansion cards or anything else within 1 month. Only difference I did was put my tower on my desk instead of the floor."

Sometimes when you move a computer connections inside the case get loosened and something is not making a good connection.

Unplug the case/power supply, or switch off the AC power to it otherwise.
Power off your monitor.
Open up the case. Check all the connections of the wiring to make sure they are all the way onto their pins and into their sockets, especially the main connector from the power supply. The wires close to the mboard going into the main power connector / socket should be more or less perpendicular to the mboard surface rather than at an angle. Make sure all cards in slots are all the way down in their slots. Make sure all ram is all the way down in it's slots, and that the latches at both ends of all the modules are against the ends of the modules.

Make sure that there is nothing metal that is loose inside the case that may have moved when you moved the case that may be shorting something on the mboard, or underneath the mboard. If you pick up the case and shake it, if there is something metal loose you will probably hear it moving.

This isn't likely since the mboard was working previously, but we have rarely seen this situation even when it had been working previously ....
- make sure that you do not have metal mounting posts in positions behind the mboard where there are no mounting holes in the mboard.

"The motherboard may well be defective but your logic as to why is faulty."

I certainly agree with that.


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#16
November 8, 2011 at 16:44:22
I stripped and tried bare essentials, Same Result, No power if plugged in.
The CPU fan does spin while 4 pin isn't in. as well as other fans.

I on average Keep computer on most of the time.

All Computer Parts are connected by Surge Protector bar

To reply to graphics, I also plug in a 6 Pin Connector into the card.

I don't have second desktop available.


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#17
November 8, 2011 at 17:44:15
What processor are you running?

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#18
November 8, 2011 at 17:45:10
The video card's geforce gtx 550 ti video chipset draws more power than anything else except the cpu and the mboard itself.Anything else you disconnect isn't drawing much power.


"I on average Keep computer on most of the time."

WHY ?

"All Computer Parts are connected by Surge Protector bar"

That won't necessarily protect against damage caused by lightning strikes.
Voltage spikes can be produced that are so high a voltage that they can get past anything, and even jump switches that are switched off.

"I don't have second desktop available"

Surely you know somone who does.

The 650 watt PS can't be eliminated as not causing the problem until you have tried it with a working system.


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#19
November 15, 2011 at 16:02:40
Any Chance the CPU could be a problem?

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#20
November 17, 2011 at 07:51:38
Ok, Things are a bit different. Most things including Graphic card with 6 Pin plugged in and 4 Pin Plugged in. I tryed using a screw driver on the power switch pins, Nothing. I do same with Reset Switch, Everything Turns on (appeares on) with no post. All Fans now work doing it this way.

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#21
November 17, 2011 at 08:44:08
Do you hear any beeps when you start up the computer? If not, try removing all RAM and boot. You should then hear a beep code.

Then you NEVER see anything on the screen?

Does your motherboard have on board graphics? If so, remove the add in card and try using the on board graphics.


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#22
November 17, 2011 at 11:25:22
One of the LEAST likely things is there's something wrong with the CPU.

You haven't said whether you checked for these things...

"Make sure that there is nothing metal that is loose inside the case that may have moved when you moved the case that may be shorting something on the mboard, or underneath the mboard. If you pick up the case and shake it, if there is something metal loose you will probably hear it moving.

This isn't likely since the mboard was working previously, but we have rarely seen this situation even when it had been working previously ....
- make sure that you do not have metal mounting posts in positions behind the mboard where there are no mounting holes in the mboard."

If you haven't, check for those things !
.........


The 400 watt PS you tried may be inadequate if it's an el-cheapo model !

You can't eliminate the possibilty the problem is with the 650 watt PS until you've tried it with another system.

If you have not tried the 650 watt PS with another desktop system yet, DO THAT !

If you can't do that, take your computer to a local repair place and have them try a decent > 400 watt PS with it !
.
If that doesn't help, your mboard is probably fried, you or the original PS or some external event probably damaged it, and there's probaby nothing wrong with anything else.

And have them try your 650 watt PS with a working computer


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#23
November 26, 2011 at 14:13:47
I have the same Problem!! my pc turn on and everything but the screen say no sign .. i cant get to the bios screen !! the whole mother boared run and the fan to .. but its want connect to the Bios screen.. is mother boared dead? if so how can you tell?

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#24
November 27, 2011 at 07:22:21
help95

Your problem is probably not the same.

Click on Start a discussion (a.k.a. start a new Topic), supply your information, tell us the make and model of your computer, and you will get more responses.


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