PC powers up, HDD and CD lights stay solid, no POST

[dseaver]

So I went to shut down my computer last night and it appeared to have locked up. I had used it 2 hours prior to it failing. I went and hard booted it and it refused to post. The HDD activity LED and CD activity light stay lit, and it wont POST. THe rig is a 4 year old P4 rig that I had built myself.

Parts (from memory until I can get home):
Asus P4E800 Deluxe (not sure on this one)
Pentium 4 3.0 (OC to 3.3)
2 X 512MB Corsair ValueSelect DDR 400 RAM
ATI 9600 All-in-Wonder Card
Audigy 2 Value
Ultra (I think) 450W PSU

Is it the Mobo that failed or the PSU maybe? I putting my bet on the Mobo for now.

 

[wahnula]

This sounds like it could be many things, from PSU to RAM, and yes, mainboard. To eliminate (or reduce) variables, try another PSU if available. If not, everyone should have a 350 watt El Cheapo PSU in the closet for just such testing purposes.

Make sure the HSF is seated correctly. Remove everything (all add-in cards, ROMs, etc.) from the build except the graphics card and 1 stick of RAM. POST? Try the other stick. POST? If so you've found the problem. If not, remove the mainboard from the case and check for burned areas under the board or bulging capacitors (

http://www.badcaps.net

has pictures). Place the board on an insulated surface (cardboard or a thick towel) and repeat the above procedure, shorting the PWR SW headers with a small flat blade screwdriver. Make sure the 4-pin PSU lead is connected.

If you still get nothing, you've reduced it to the mainboard, CPU, and graphics card, and of course the PSU which should have been the first thing checked.

I never regret telling folks to buy a spare PSU, even if it doesn't solve the problem at hand. As I mentioned, it will come in handy sooner or later.

Tony

Users helping Users...

 

[dseaver]

Yea, i just haven't had the time to actually trouble shoot it, I pulled out the power from the HDDs and no post, and i removed the video card and no post. I plan to do a proper diagnostic soon. I gotta see if I can harvest a PSU from somewhere to check that. The comp was working 2 hours prior and had not been rebooted or anything. I have never had any problems in the 4 years of using it, but this may prove as a time to build a new rig

 

[dseaver]

My mobo is a Asus P4P800-E Deluxe, found it while browsing the Asus site, and it rung a bell

 

[BadBigBen]

I agree with wahnula, about having a spare PSU (I do have one - 1100watt Galaxy which hooks up to almost all mainboards out there)... of course on the bare parts diag aswell...

I also agree that you should check the PSU first, one rail may have bit the dust... since the HDD's and Fans are getting power, I am thinking that either a 5v or the 3.3v rail busted...

alternatively, the PSU you have may be of the good sort, in which it will refuse to power anything after a spike in the powermains. These tend to let themselves be reset, by unplugging the powercord and then holding the power on button for a few minutes...

remove the IDE cable (from the mainboard not the drive) and not just the power to the HDD!!! can't stress this enough...

Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

 

[jlockley]

Fan working?

BBB/wahnula: could it be the same issue as the ACER splash screen you helped me with?

 

[BadBigBen]

jlockley - of course it could be the same issue, and thanks for reminding me... I tend to forget that sometimes...

as Jlockley pointed out, remove any USB devices before powering up and see if that is the cause...

Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

 

[dseaver]

i unplugged everything from the mobo and tried turning it on and still no post. I used a multimeter and measured the 5 and 12 v from the molex connectors and got ~5 and ~11.6 v respectively. i even pulled out the ram and got no beeps from the mobo. i dont have a spare psu to test that otherwise. any suggestions?

 

[BadBigBen]

From testing at the molex conn, you only get 2 of the 8 or so rails on a PSU... There are 3.3v, +5v, +12v, -12v rails on a PSU, and depending on the quality there are several of each, e.g. on my SilverStone 600watt PSU, I have one +3.3v rail, two +5.5v rails, one -12v rail, and four +12v rails...

~ means AC voltage usually... I am sure that this is a typo on your part, as it should be DC ...

without another PSU (borrow one from a friend or get an El-Cheapo from eBay or somewhere else) for testing, you will get the symptoms even with all the parts removed...



Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

 

[smah]

Does it have an add-on modem card? If so, pull that & test.

 

[dseaver]

No add on card
And the ~ i used was to represent approximately, not AC, i know it was DC, but thank you

 

[dseaver]

I'm going to be able to test a PSU to see if that is the problem, I tried a PSU out of a Dell Dimension 4600 that had a 20 pin connector, and the mobo would flick on for a sec and not stay on. Is there a way to test my PSU with my multimeter or would the best way to test it would be by trying a known working one? Thanks!

 

[BadBigBen]

dseaver, see the following:

Testing your PSU with a multimeter

http://www.driverheaven.net/guides/testingPSU/

How To: Test PSU Voltages

http://www.ochardware.com/articles/psuvolt/psuvolt.html

the article from OC Hardware probably explains it best ...

Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

 

[G0AOZ]

Ben has highlighted a couple of very good, useful articles for you, detailing the voltage connections for PSUs.

The problem you have though is that your computer isn't working! To test a PSU, one really needs to check it under load as voltage rails can sag with increased current demand if the unit is faulty.

Whilst the multimeter check will initially tell you if one or more of the rails has dropped or is zero volts, unless you have equipment to specifically put a load on the PSU, replacement with a known good one of equal Wattage rating or better, is probably going to be your only option.

Good luck.

ROGER - G0AOZ.

 

[dseaver]

Thanks Ben and Roger, Ben for the helpful links and Roger for letting me know that even if I did test it, it doesn't help me!

 

[G0AOZ]

...for letting me know that even if I did test it, it doesn't help me!".

Well I wouldn't go quite that far! At least the multimeter test would show you if a voltage rail was already sagging or right down at zero. However, if you DON'T find anything amiss, then it MAYBE because the PSU isn't being fully loaded when you test it...

ROGER - G0AOZ.

 

[dseaver]

I tried a PSU out of a Dell Dimension 4600 that had a 20 pin connector, and the mobo would flick on for a sec and not stay on. I also tried a mini-atx power supply (180W) with just the motherboard plugged in (no peripherals, no PCI cards, nothing but the 20 pin connector and the 4 pin processor power) and it flicked on for a fraction of a second when i pressed the power and refused to try again until i unplugged the PSU. Is it officially the motherboard?

 

[BadBigBen]

on to STEP 2:

check the HS FAN, most mobo's will not power up, if they detect a malfunctioning HS FAN...

test by unplugging the FAN and plugging another one in it's place (must have the third sensor cable)... DO NOT REMOVE THE HEATSINK at this stage, doing so may damage the CPU...



Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

 

[dseaver]

Well.., when my original PSU is plugged in, its stays powered up, just locked up. And I know the HS fan works then, because it lights up and spins (I have one of those fancy HS). It only flicks on for a second when OTHER power supplies are hooked up. It won't post with any of the PSUs though

 

[dseaver]

It is the motherboard. I had to use the PSU to power another board because the one I had wasn't working and the PSU from my rig worked fine, but the Mobo doesn't