Mobo won't power on - 8 pin CPU atx 12v?

LifeOnMars · Jan 31, 2010, 12:06 AM

Now here's what I've found: I can connect the 24 pin ATX power cable and the entire computer will turn on: the fans and everything else is running, all except for the CPU which isn't receiving power and the graphics card doesn't spin up. As soon as I plug the 8 pin ATX 12v cable that's supposed to power the CPU, the computer will no longer turn on. It'll turn on for a milisecond and instantly turn itself off.

I am using -

antec 900
fsp everest 800w psu
p5n-t deluxe mb
q6600 go
true 120 cooler
4 gb xms 2 corsair 800
320 gb seagate sata ii HD
bfg gtx 275 oc

so what could be the problem guys? Grounding issue?psu? Dead mobo or CPU?

What's the minimum you need for it to power up, for example would it power on without the graphics card in place?

It someones old system that I have bought so I know all the components have worked together.

LifeOnMars · Jan 31, 2010, 02:08 AM

Anyone help in anyway on this please?

theonedub · Jan 31, 2010, 02:11 AM

You will need a GPU since there is not an onboard solution. Try using the 4pin 12v AUX plug instead of the 8pin and see if it does the same thing. Are you sure the GPU is installed correctly and plugged in as well? As always try it with CPU, GPU, 1 stick of ram, no HD, and see if you can get it to enter the BIOS.

Mussels · Jan 31, 2010, 02:14 AM

mobo, PSU, ram, video card. Thats the minimum for a power on.

the fact that its turning on then off again, means its detecting something is wrong - likely, you forgot something.

LifeOnMars · Jan 31, 2010, 02:20 AM

Hi and thanks for the reply. It comes with two 4 pin plugs and I have tried it with both, and each one on their own all with the same result. Without any CPU power plugged in the psu fan spins, the case fans spin, the fan mounted to the true spins, the DVD has power, but the graphics card does not spin. When CPU power is added it turns on then instantly off

LifeOnMars · Jan 31, 2010, 02:24 AM

Quote:

Originally Posted by Mussels

mobo, PSU, ram, video card. Thats the minimum for a power on.

the fact that its turning on then off again, means its detecting something is wrong - likely, you forgot something.

Hi mussels. I have 24 pin, 8 pin atx, two pcie 6 pins, case power switch connection, ram in place, case fans, CPU fan all connected... Anything I have missed?

Mussels · Jan 31, 2010, 02:26 AM

that list just confuses me :P

Motherboard: 24 pin, 8 pin, any aux power it needs (floppy/molex connectors, some boards have em)
Video card: all PCI-E power connected
Ram: one stick, try various slots. if no luck, try another stick in several slots.

During this, everything else should be disconnected. no HDD's, no DVD burner, no fans except for PSU, CPU and VGA.

LifeOnMars · Jan 31, 2010, 02:29 AM

Sorry for any confusion

as the true is passive it's ok to try turning on the system without it's mounted fan isn't it?

theonedub · Jan 31, 2010, 02:30 AM

Unless that board has a feature where it does not power on if there is no fan connected to the CPU Fan header. Might want to check that out.

Mussels · Jan 31, 2010, 02:31 AM

Quote:

Originally Posted by theonedub

Unless that board has a feature where it does not power on if there is no fan connected to the CPU Fan header. Might want to check that out.

^ what he said.

make sure the fan you use has an RPM sensor as well, or it wont detect it. (hint: use the fan from the stock cooler)

LifeOnMars · Jan 31, 2010, 02:32 AM

Also if I have no joy with the above suggestions is it worth setting the whole thing up outside the case to make sure the case is not shorting it out?

Mussels · Jan 31, 2010, 02:33 AM

Quote:

Originally Posted by LifeOnMars

Also if I have no joy with the above suggestions is it worth setting the whole thing up outside the case to make sure the case is not shorting it out?

yes.

LifeOnMars · Jan 31, 2010, 04:14 AM

Ok just tried it all outside of the case and tried it with 4 different sticks of ram in all 4 slots individually. Exactly the same outcome

but hopefully at least, that rules out any shorts happening inside the case. I also cleared the CMOS a few times just to check that as well. I have another psu arriving Monday so hopefully that may solve the problem or at least narrow the cause of the problem down a bit.

Mussels · Jan 31, 2010, 04:26 AM

the only real thing left for you to do, is swap components with known good ones - test CPU, ram, PSU, and video card in another machine for example.

LifeOnMars · Jan 31, 2010, 10:21 AM

Quote:

Originally Posted by Mussels

the only real thing left for you to do, is swap components with known good ones - test CPU, ram, PSU, and video card in another machine for example.

Yeah and that's where things really suck. I've had to wait ages to afford to get this and then this

well hopefully I can eliminate the power supply tomorrow and then take it from there...I'm absolutely gutted but that's life I guess. Thanks for the help so far guys and I'll keep updating the thread with any success or findings.

dr emulator (madmax) · Jan 31, 2010, 10:29 AM

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you haven't got the 8 pin mobo plug mixed up with your pciexpress plug? that would spell smokin mobo
have you tested the psu with a multimeter in situ?

LifeOnMars · Jan 31, 2010, 10:36 AM

Quote:

Originally Posted by dr emulator (madmax)

Attachment 32693 you haven't got the 8 pin mobo plug mixed up with your pciexpress plug? that would spell smokin mobo
have you tested the psu with a multimeter in situ?

Nope no mix up on the plugs. Don't have a multimeter and can't really buy anything else at the moment so I'm stuck. Another member from the uk has said he will help by testing components on his system so will try new power supply tomorrow and if there is no joy I'll start posting him stuff to test out for me...that's if I can afford postage,yes, it's that bad.

dr emulator (madmax) · Jan 31, 2010, 11:15 AM

shame ya don't live near me

LifeOnMars · Jan 31, 2010, 12:20 PM

I moved here recently and don't really know anyone locally although I think alexp one of the moderators lives around my neck of the woods.

LifeOnMars · Jan 31, 2010, 01:09 PM

I'm bored so I'm gonna remove the thermalright ultra and clean it. The idiot who shipped the computer left it attached so whilst I have it removed I'm going to check the CPU and socket for any damage. As I have only used amd previously is there anything that would signify damage to the processoer or the socket? also what's the best thing to use for cleaning the thermalright ultra, I was just going to use a cotton bud to clean all the dust of it, is that ok?

brandonwh64 · Jan 31, 2010, 01:10 PM

look for bent pins in the CPU socket and if there is then thats your culprit

Bo$$ · Jan 31, 2010, 01:28 PM

plug in the cpu 8pin,take out the graphics card, does it still turn off?

LifeOnMars · Jan 31, 2010, 01:29 PM

Cheers brandon for your continued support mate

brandonwh64 · Jan 31, 2010, 01:31 PM

YW. this problem seems like as i said in the other thread that it could be a bad motherboard or a corrupted bios but its hard to tell. if you can find another motherboard or CPU to test that would be best

dr emulator (madmax) · Jan 31, 2010, 01:32 PM

ye it's a shame you don't live near here, as i would have been able to whisk that cooler of to my uncles garage, and use the air compressor to blast the dust out , if it's aluminium i would wash it under the tap then use a hair dryer to dry it out

Jan 31, 2010, 12:06 AM	#1
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	Mobo won't power on - 8 pin CPU atx 12v? Now here's what I've found: I can connect the 24 pin ATX power cable and the entire computer will turn on: the fans and everything else is running, all except for the CPU which isn't receiving power and the graphics card doesn't spin up. As soon as I plug the 8 pin ATX 12v cable that's supposed to power the CPU, the computer will no longer turn on. It'll turn on for a milisecond and instantly turn itself off. I am using - antec 900 fsp everest 800w psu p5n-t deluxe mb q6600 go true 120 cooler 4 gb xms 2 corsair 800 320 gb seagate sata ii HD bfg gtx 275 oc so what could be the problem guys? Grounding issue?psu? Dead mobo or CPU? What's the minimum you need for it to power up, for example would it power on without the graphics card in place? It someones old system that I have bought so I know all the components have worked together.

Jan 31, 2010, 02:11 AM	#3
theonedub habe fidem Join Date: Apr 2009 Location: Northern CA Posts: 6,622 (4.45/day) Thanks: 2,277 Thanked 3,198 Times in 1,927 Posts System Specs	You will need a GPU since there is not an onboard solution. Try using the 4pin 12v AUX plug instead of the 8pin and see if it does the same thing. Are you sure the GPU is installed correctly and plugged in as well? As always try it with CPU, GPU, 1 stick of ram, no HD, and see if you can get it to enter the BIOS. __________________ My Heatware Feedback 129+ Pristine

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Hard Disk:	256gb Corsair Performance Pro, 2TB Caviar Green, 2TB Samsung F4
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Jan 31, 2010, 02:14 AM	#4
Mussels Doctor Moderator Join Date: Oct 2004 Location: Bendigo, Australia (NOT THE USA) Posts: 34,564 (10.96/day) Thanks: 3,700 Thanked 8,698 Times in 6,395 Posts System Specs	mobo, PSU, ram, video card. Thats the minimum for a power on. the fact that its turning on then off again, means its detecting something is wrong - likely, you forgot something. __________________ Edumacational thread about PC Audio My external HDD's.5x samsung 1TB + 2x Seagate 1.5TB = 8 TB external storage 32 Bit OS vs 64 bit OS information How to get hardware accelerated H264 playback (DXVA) Netbook Owners United!

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PSU:	Corsair HX 1000W
Software:	Windows 7 Ultimate x64 - kaspersky internet security 2013
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Jan 31, 2010, 02:08 AM	#2
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	Anyone help in anyway on this please?

Jan 31, 2010, 02:20 AM	#5
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	Hi and thanks for the reply. It comes with two 4 pin plugs and I have tried it with both, and each one on their own all with the same result. Without any CPU power plugged in the psu fan spins, the case fans spin, the fan mounted to the true spins, the DVD has power, but the graphics card does not spin. When CPU power is added it turns on then instantly off

Jan 31, 2010, 02:26 AM	#7
Mussels Doctor Moderator Join Date: Oct 2004 Location: Bendigo, Australia (NOT THE USA) Posts: 34,564 (10.96/day) Thanks: 3,700 Thanked 8,698 Times in 6,395 Posts System Specs	that list just confuses me :P Motherboard: 24 pin, 8 pin, any aux power it needs (floppy/molex connectors, some boards have em) Video card: all PCI-E power connected Ram: one stick, try various slots. if no luck, try another stick in several slots. During this, everything else should be disconnected. no HDD's, no DVD burner, no fans except for PSU, CPU and VGA. __________________ Edumacational thread about PC Audio My external HDD's.5x samsung 1TB + 2x Seagate 1.5TB = 8 TB external storage 32 Bit OS vs 64 bit OS information How to get hardware accelerated H264 playback (DXVA) Netbook Owners United!

Jan 31, 2010, 02:29 AM	#8
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	Sorry for any confusion as the true is passive it's ok to try turning on the system without it's mounted fan isn't it?

Jan 31, 2010, 02:30 AM	#9
theonedub habe fidem Join Date: Apr 2009 Location: Northern CA Posts: 6,622 (4.45/day) Thanks: 2,277 Thanked 3,198 Times in 1,927 Posts System Specs	Unless that board has a feature where it does not power on if there is no fan connected to the CPU Fan header. Might want to check that out. __________________ My Heatware Feedback 129+ Pristine

Jan 31, 2010, 02:32 AM	#11
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	Also if I have no joy with the above suggestions is it worth setting the whole thing up outside the case to make sure the case is not shorting it out?

Jan 31, 2010, 04:14 AM	#13
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	Ok just tried it all outside of the case and tried it with 4 different sticks of ram in all 4 slots individually. Exactly the same outcome but hopefully at least, that rules out any shorts happening inside the case. I also cleared the CMOS a few times just to check that as well. I have another psu arriving Monday so hopefully that may solve the problem or at least narrow the cause of the problem down a bit.

Jan 31, 2010, 04:26 AM	#14
Mussels Doctor Moderator Join Date: Oct 2004 Location: Bendigo, Australia (NOT THE USA) Posts: 34,564 (10.96/day) Thanks: 3,700 Thanked 8,698 Times in 6,395 Posts System Specs	the only real thing left for you to do, is swap components with known good ones - test CPU, ram, PSU, and video card in another machine for example. __________________ Edumacational thread about PC Audio My external HDD's.5x samsung 1TB + 2x Seagate 1.5TB = 8 TB external storage 32 Bit OS vs 64 bit OS information How to get hardware accelerated H264 playback (DXVA) Netbook Owners United!

Jan 31, 2010, 10:29 AM	#16
dr emulator (madmax) Join Date: May 2009 Location: the uk that's all you need to know ;) Posts: 1,107 (0.75/day) Thanks: 757 Thanked 181 Times in 169 Posts System Specs	you haven't got the 8 pin mobo plug mixed up with your pciexpress plug? that would spell smokin mobo have you tested the psu with a multimeter in situ? __________________ advice on what type of memory that's needed for the GIGABYTE X58A-UD7 Thanks to stefanels for the signature post pics of your bizaare mods - GPU-Z v0.6.6 is out

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Jan 31, 2010, 11:15 AM	#18
dr emulator (madmax) Join Date: May 2009 Location: the uk that's all you need to know ;) Posts: 1,107 (0.75/day) Thanks: 757 Thanked 181 Times in 169 Posts System Specs	shame ya don't live near me __________________ advice on what type of memory that's needed for the GIGABYTE X58A-UD7 Thanks to stefanels for the signature post pics of your bizaare mods - GPU-Z v0.6.6 is out

Jan 31, 2010, 12:20 PM	#19
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	I moved here recently and don't really know anyone locally although I think alexp one of the moderators lives around my neck of the woods.

Jan 31, 2010, 01:09 PM	#20
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	I'm bored so I'm gonna remove the thermalright ultra and clean it. The idiot who shipped the computer left it attached so whilst I have it removed I'm going to check the CPU and socket for any damage. As I have only used amd previously is there anything that would signify damage to the processoer or the socket? also what's the best thing to use for cleaning the thermalright ultra, I was just going to use a cotton bud to clean all the dust of it, is that ok?

Jan 31, 2010, 01:10 PM	#21
brandonwh64 Addicted to Bacon and StarCrunches!!! Join Date: Sep 2009 Location: Chatsworth, GA Posts: 13,572 (10.00/day) Thanks: 2,149 Thanked 5,342 Times in 3,697 Posts System Specs	look for bent pins in the CPU socket and if there is then thats your culprit __________________ Cruncher's: All GPU's GPU's: 7970 3GB Unlocked = 8 Threads 5770 1GB OCed = 2 Threads

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Jan 31, 2010, 01:28 PM	#22
Bo$$ Join Date: May 2009 Location: London, UK Posts: 3,672 (2.48/day) Thanks: 444 Thanked 770 Times in 679 Posts System Specs	plug in the cpu 8pin,take out the graphics card, does it still turn off? __________________ Live in the UK? Join the UK TPU Group! Caution! This is Sparta! Im Looking For... Im Selling

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Jan 31, 2010, 01:29 PM	#23
LifeOnMars Join Date: Jun 2008 Location: Kettering,Northants. UK Posts: 2,242 (1.25/day) Thanks: 1,718 Thanked 401 Times in 337 Posts System Specs	Cheers brandon for your continued support mate

Jan 31, 2010, 01:31 PM	#24
brandonwh64 Addicted to Bacon and StarCrunches!!! Join Date: Sep 2009 Location: Chatsworth, GA Posts: 13,572 (10.00/day) Thanks: 2,149 Thanked 5,342 Times in 3,697 Posts System Specs	YW. this problem seems like as i said in the other thread that it could be a bad motherboard or a corrupted bios but its hard to tell. if you can find another motherboard or CPU to test that would be best __________________ Cruncher's: All GPU's GPU's: 7970 3GB Unlocked = 8 Threads 5770 1GB OCed = 2 Threads

Jan 31, 2010, 01:32 PM	#25
dr emulator (madmax) Join Date: May 2009 Location: the uk that's all you need to know ;) Posts: 1,107 (0.75/day) Thanks: 757 Thanked 181 Times in 169 Posts System Specs	ye it's a shame you don't live near here, as i would have been able to whisk that cooler of to my uncles garage, and use the air compressor to blast the dust out , if it's aluminium i would wash it under the tap then use a hair dryer to dry it out __________________ advice on what type of memory that's needed for the GIGABYTE X58A-UD7 Thanks to stefanels for the signature post pics of your bizaare mods - GPU-Z v0.6.6 is out

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