Help Needed - Possible Powersupply Problem

lance_biscuit

lance_biscuit

lance_biscuit

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30 Aug 2005
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The other day I installed a fresh copy of xp, ever since the computer would turn itself off pretty much whenever it feels like it, even when trying to reinstall xp. I think it could be a power supply problem, i've got the crosair 850w? Any ideas on how I would establish if its this other than trying to use an alternative psu?

Any help greatly appreciated!

Cheers
 
You could go into the bios and check voltage lines,although it won't be particularly accurate.The only way of truly testing a PSU would be to use a voltmeter.

Other than that,try testing the RAM..I've had many a windows installation problem down to dodgy RAM.
 
Was just thinking of checking around the bios, but now the pc refuses to boot and when it does it just turns off again, if i press the power button the fans start to pin a little and then stop. its like its cutting out for safety, would you think psu then?
 
Hi Lance,

I am getting the exact same problem as you, my computer literally just cuts out and restarts at random intervals, no warning or error. Totally random. I just got a new harddrive and reisntalled windows there yesterday and it was ok until a few hours ago when it started playing up again. I'm pretty sure it is not a virus.

My dad seems to think it is the PSU, my psu is a enermax noisetaker 600w that I just got it a few months back.
 
Hi Zinc, yeah I think it must be the psu now, its not even letting me start it and when it was rebooting it wasn't giving me any errors when i disabled the automatic restart, so not a driver issue, what a pain now, got to package this up and send it back!
 
What motherboard is this happening on guys?
I had the same problem with a asus a8n-sli S939 deluxe board untill eventerly it just would not post again.
 
It's quite an old motherboard, its a DFI NForce 4 SLI-DR 939.

Might it be overheating? My room tends to be quite warm, sometimes over 26C. I will go and check the temps on the motherboard in the bios and post back.
 
Mines a Asus P5K, I've just done a test on the psu though, by touching two pins together as per crosairs website support, and it barely turns the 120m fan thats in my antec p180, so that would indicate to me that its the psu faulty, it didn't have enough puff to drive it around. So im gonna rma it personally.
 
To test your PSU,short out any black and green wire in the large ATX connector.Just make sure you're holding onto an insulated bit of wire :D

Best to wire up a drive to the PSU for loading..

If the same symptoms occur,then it's the PSU.
 
Just left the pc for the day while at work, came back and retried the psu test, it passed this time, started up the pc, into windows setup and then waiting for it to load that up and it turned off again, would it be the motherboard?

Never had any issues with mbs tbh, and have plenty of brands, dfi, sparkle, gigabyte and previous asus's. If it is the mb, I'll be livid, got all the wiring sorta decent in the rig!

Whats asus's return procedure like?

Cheers
 
I got one that does this.....MSI Neo 2 and OCZ powerstream.
It's my spare PC, and it's so random its very hard to diagnose.

It may shut down at boot or be fine for a hours on end....very frustrasting. Hit the ON button after it's died and away it goes.

I suppose as it's not my main PC I'm not to bothered, but it would be a lot easier in some ways if it just stopped working period then I may have an idea what it is.
I'm torn between the motherboard and the PSU, and I will have to try another PSU I guess, but like all things you dont use often...it's like "I'll do that when I have the time".
I feel guilty now for not doing it ;)

To answer your question...yes it can be the motherboard...if say the mobo blips and Power Good doesn't get a signal it shuts down..
20pin24pinconnectoroe2.jpg


Hmm in fact it could be something else attached to the system going out of spec.
This is from ATX form factors.

PWR_OK
PWR_OK is a “power good” signal. This signal should be asserted high by the power
supply to indicate that the +12 VDC, +5 VDC, and +3.3 VDC outputs are within the
regulation thresholds listed in Table 15 and that sufficient mains energy is stored by the
converter to guarantee continuous power operation within specification for at least the
duration specified in Section 3.2.9. Conversely, PWR_OK should be de-asserted to a
low state when any of the +12 VDC, +5 VDC, or +3.3 VDC output voltages falls below
its under voltage threshold, or when mains power has been removed for a time
sufficiently long such that power supply operation cannot be guaranteed. The electrical
and timing characteristics of the PWR_OK signal are given in Table 21 and in Figure 2.
 
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Thing is that the mb shows the green light indicating that its getting power, and i've only managed to get the fan to spin up by the green and a black pin on one of the black pins, but I think thats just due to the fact that its hard to get a contact.

The system doesn't even boot at all now, I tried resetting the rtc (cmos) to see if it had something to do with that but that was a no go aswell.

Do i have to return the board to asus or does overclockers handle it? I've had it for a few months now!
 
lance_biscuit said:
Thing is that the mb shows the green light indicating that its getting power, and i've only managed to get the fan to spin up by the green and a black pin on one of the black pins, but I think thats just due to the fact that its hard to get a contact.

The system doesn't even boot at all now, I tried resetting the rtc (cmos) to see if it had something to do with that but that was a no go aswell.

Do i have to return the board to asus or does overclockers handle it? I've had it for a few months now!
Click to expand...

Don't assume it's the motherboard just as it has a green light on.
I was given a dead PC to fix the other day, and when I turned it on to test it a light on the keyboard lit up...Duh I thought, its not going to be an easy PSU fix.
Anyway I took it out and stuck my DMM on it while connecting green and black and it gave me a big 0 on my DMM.
One new PSU later and I had a working PC.

Get yourself a cheap DMM and look say here.
For 24 pin ATX see the picture in my other post.
 
I think you misread that last post mate, I'm assuming its the motherboard because the fan is spinning up when I do the green and a black pin test. I've no other basis to work off, other than possibly buying some sort of psu testing equipment.

I will give a dmm a try though, could be handy!
 
lance_biscuit said:
I think you misread that last post mate, I'm assuming its the motherboard because the fan is spinning up when I do the green and a black pin test. I've no other basis to work off, other than possibly buying some sort of psu testing equipment.

I will give a dmm a try though, could be handy!
Click to expand...


Duh me...I did sorry :(
DMM is handy tool tho, and it's only 12 volts so it aint gonna kill you ;)
 
As suggested i got a dmm tonight, checked all the leads off the main lead 20/24pin lead and some of the molex, everything seems fine with the psu, even getting 12v and 5v bang on on each. Its crazy, so is the general concensus now motherboard?
 
lance_biscuit said:
As suggested i got a dmm tonight, checked all the leads off the main lead 20/24pin lead and some of the molex, everything seems fine with the psu, even getting 12v and 5v bang on on each. Its crazy, so is the general concensus now motherboard?
Click to expand...

Put it this way, it's the next logical step and it sounds like it *should* be the motherboard.
I seem to remember we had a failure thread on here once, and was something like 20 mobos to one CPU failure.
I take it you've stripped it to a bare minimum and tried it?
 
You need to test the psu on another board with your gpu I reckon.
 
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Yeah I've tried the psu in the system with only the mb, gfx card and a hard drive connected and once without the hard drive too. I get nothing at all from it. I unfortunately don't have another mb to test it along with as I passed on my old hardware to other people.
 
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