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Jan 31st, 2007
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PC won't power - green LED on motherboard, new power supply

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Sorry for the non-specific title. I'll try and elaborate more here.

I went over the 'MY PC Won't Start' sticky, and did a search for other titles, but my problem seems to fall in-between troubleshooting steps that I see.

By that I mean, when I hit the power button on the front panel of my case, nothing on the inside of the case happens at all except I see one of the case lights come on for just a second; along with the temperature display on the front of the case.

I hear no fan, I hear no hard drive spinning, not even any semblance of a start when I hit the power button; simply quiet.

Now, my PC was working fine earlier today, but I received a new video card; eVGA GeForce 7950GT to replace a GeForce 6600. I have a ASUS P5ND2-SLI motherboard, and I believe but I'm not certain a Raidmax case, one of the ones with an openable panel door covering the drivebays and such and has a temperature display.

So after I installed the 7950 and tried to power back up, the aforementioned happened. I tried the second PCI-E port with the new card, and the same thing happened. Finally I switched back in the 6600 which has been functioning with the PC for over a year, and the same exact problem persisted.


Things I'm relatively sure of:

1. There's two really important power connectors to the motherboard? ATX12V as labeled on my motherboard manual, and the really huge one which is I guess abbreviated with a long string of letters and numbers (sorry don't know it's general name). I'm certain both of those are attached.

I'm certain the CPU-FAN power is attached.

2. The power supply voltage is set to 110, which it always has been. I can see inside of my case when the power is connected, that the motherboard LED light is green.



That's about it...I didn't build this PC, but I did replace the power supply about a month ago so had a bit of experience in doing that. I have no idea if maybe I've unintentionally disrupted power from the case to the motherboard somehow.

Any clues of what I may've done wrong is appreciated! I'm also able to take digital photos if that'll help and upload them.

I'm also willing to take it to a technician in the morning if you believe something is really wrong.

Thanks!
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Re: PC won't power - green LED on motherboard, new power supply

Some more information:

1. The power supply is less than a month old, but it's just an Antec 500w power supply. My old one was a Raidmax, I don't know remember the watts but it came with a Raidmax X1 case; the entire system prebuilt by ibuypower and parts suggested through their order form thing last February.

2. I went into my case and checked all the wires again, everything is attached firmly. I redid the power button wiring to the motherboard according to the motherboard manual.

It still just lights up briefly, the LED lights on the front panel and the case lightning. I don't hear any hard drive spin or numerous fans; but I do hear a noise now.

The noise I hear is um...kind of a clatter. It isn't really loud, or loud at all really, but not a noise I'm accustomed to hearing. Pressing the power button isn't dependable on getting even that meek response, it just happens at random, but I watched the blades on my power supply fan, and both case fans; neither moved so I don't think the noise is from that.

Could be the harddrive making the noise? It only lasts a second.


Anyway, I wasn't sure about the case to motherboard connection before, but I kind of am now. The LED light on my motherboard is still green. Everything is firmly attached into the motherboard.

Would it be unwise to purchase a beefier power supply and assume that it's that?

As long as I've had it, my PC has been running a tad hotter and a lot louder after replacing my old Raidmax power supply with the Antec one.

Maybe the 7950GT made it croak at first time trying to power it?
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Re: PC won't power - green LED on motherboard, new power supply

The listed requirements for a PSU for that card is 400W, and that Antec is a good PSU, I don't think this is your problem.

The noise that you hear when it first starts could also be you optical devices spinning up, and yes it could be the hdd. Is the six pin power connector from the PCIe plugged in?

The coincidence of this happening immediately after changing the card makes me wonder if you loosened something in the process. I would go back and re-seat all of your cards, RAM, power connections.
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Re: PC won't power - green LED on motherboard, new power supply

The six pin cable is connected directly from the power supply to the 7950GT, yes. I've made certain all the cables are firmly attached to the power supply, and everything they're connected to.

Everything looks pretty familiar and as it's always been...I'm not too computer savvy obviously but honestly I can't think of anything I did wrong.

This is my first time swapping things in a PCI-e slot, but I've swapped things in PCI and AGP slots tons of times in the past. I simply unscrewed the last one, freed it from the little white latch thing, pulled it out, put in the new one, figured the cord labelled 'PCI-e' that came with my Antec awhile ago was meant for it's six pin and connected it to the power supply. Screwed it in and tried to power up..no go.

Put in the old 6600, no go on that either.

I have no idea what I could have done...

Things I've tried besides making sure everything is firmly attached (after unattaching and reattaching):

1. Tried what I could from the stickies and other suggestions in posts that apply to me. Removed the CMOS battery for 10 minutes, put it back in, same results.

2. Tried using just one stick of RAM in the third slot (some odd ASUS suggestion I guess), same results. So I'm back to using two memory sticks as they originally were, but in the process took both out, put both back in, made sure they were firmly latched in by the white thingies.



Thanks for trying to help me...I appreciate it.
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Re: PC won't power - green LED on motherboard, new power supply

Are you getting any beep codes from the motherboard?

You can eliminate the PSU being the problem with this test. First unplug the computer from the wall receptacle, remove the PSU connectors from the motherboard, on the 24 pin connector there is one green wire, place a jumper from the green wire to any black wire, plug the computer back in and see if the PSU fan runs and stays on.
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Re: PC won't power - green LED on motherboard, new power supply

No beeps from the motherboard.

Power supply seems to be working, I used one of those Antec power supply testers and everything is all green. Should I go ahead and try your method of testing it anyway?

If not, maybe this boils it down to either a dead processor or motherboard?

Thanks again for the help.
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Re: PC won't power - green LED on motherboard, new power supply

So after unattaching everything again in order to run that power supply tester, and reattaching everything, my PC powered on and stayed on. Unfortunately I didn't have a monitor or peripherals attached to it at the time so I didn't get to see any start up screens.

I shut it down after a minute or so, reason why being I looked around the case to check all of the fans and noticed the power supply fan isn't spinning?

I shut down thinking maybe that would cause it to mess up or something, and I don't want to start up again until I resolve that.

Firstly though, the ONLY thing I knowingly myself did different than all the unattaching and reattaching everything all night and morning was...

1. Tuck excess power cable length and power connectors into empty drivebay.

2. There's this little three-pin white connector thing on my side-panel (the one that slides off) case fan. Everytime I open my PC, it comes off of it's motherboard connector. I'm pretty sure I always had this little three-pin thing connected to the motherboard, but on impulse I decided to not bother reconnecting it this time.


Those are the only two things I did different, and it did start. So my questions about those are, could it have been the cords and unused connectors touching anything that made it not power on correct?

That little three-pin connector I mentioned on my side case fan, I always thought that was a sensor or somesuch so that programs like Everest can read the fan speed and what not. Is it something mostlikely more vital or not vital that I know?


Oh and most importantly, my power supply fan not moving but the PC powering up just fine. Faulty power supply? There's this blue and black thin-wired three or four pin connector coming from out of the power supply, but it's attached to nothing (never has...leads me to believe maybe my power supply fan NEVER worked. I'm stupid)

Is that perhaps what controls the power supply?

LASTLY (sorry for rambling) is the fact that it started up, and ran for a good minute indication that my processor and motherboard are ok? Would be good news to hear...

Thanks again, sorry for being so long winded.
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Re: PC won't power - green LED on motherboard, new power supply

Click to Expand / Collapse  Quote originally posted by fromset ...
So after unattaching everything again in order to run that power supply tester, and reattaching everything, my PC powered on and stayed on. Unfortunately I didn't have a monitor or peripherals attached to it at the time so I didn't get to see any start up screens.

I shut it down after a minute or so, reason why being I looked around the case to check all of the fans and noticed the power supply fan isn't spinning?

I shut down thinking maybe that would cause it to mess up or something, and I don't want to start up again until I resolve that.

Firstly though, the ONLY thing I knowingly myself did different than all the unattaching and reattaching everything all night and morning was...

1. Tuck excess power cable length and power connectors into empty drivebay.

2. There's this little three-pin white connector thing on my side-panel (the one that slides off) case fan. Everytime I open my PC, it comes off of it's motherboard connector. I'm pretty sure I always had this little three-pin thing connected to the motherboard, but on impulse I decided to not bother reconnecting it this time.


Those are the only two things I did different, and it did start. So my questions about those are, could it have been the cords and unused connectors touching anything that made it not power on correct?

That little three-pin connector I mentioned on my side case fan, I always thought that was a sensor or somesuch so that programs like Everest can read the fan speed and what not. Is it something mostlikely more vital or not vital that I know?


Oh and most importantly, my power supply fan not moving but the PC powering up just fine. Faulty power supply? There's this blue and black thin-wired three or four pin connector coming from out of the power supply, but it's attached to nothing (never has...leads me to believe maybe my power supply fan NEVER worked. I'm stupid)

Is that perhaps what controls the power supply?

LASTLY (sorry for rambling) is the fact that it started up, and ran for a good minute indication that my processor and motherboard are ok? Would be good news to hear...

Thanks again, sorry for being so long winded.


Hello guys, I faced the same problems it was due to bios set to
chassic switch mode and several casing hv the switch is a two/three
wire connector like CPU fan type if it not connected to mobo even
closing up the casing is a NO GO. Now I wl settle off this feature
in the bios B4 I opens up my PC.

Thanks

MIKE NG
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Re: PC won't power - green LED on motherboard, new power supply

Could be the power button also.if the light on the MOBO is on then it is getting power and you checked all cables and stuff said they were seated and connected good.could be as simple as the power button itself.
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Re: PC won't power - green LED on motherboard, new power supply

When I turn on my pc the Power Supply dont go on just my fornt panel green light stays on
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This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.
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