PSU or MoBo problem?

Hi guys. I’m having a problem with my PC that i’m having trouble diagnosing.

If the PC is off for a relatively long amount of time (say 5-6 hours) and i turn it on, it usually hangs at some point during the boot-up process or after windows loads. It has hung on pretty much any screen during the boot-up process (the 1st screen where it shows the video card info, the mem testing screen, drives loading screen, windows booting screen, windows desktop etc.)

I wanted to rule out some components, so i’ve unplugged the hard drives, optical drives, video and sound cards etc. It still hangs.

Thing is it even hangs if i go into the bios and let it stay on that screen.

i’m pretty sure it’s either the motherboard or the PSU. I’ve ruled out the RAM by using an older 512 MB stick i had lying around and the problem persists.

I’ve been going through this process everyday . Eventually, it gets stable and i can use it. I’m using it now and i am completely sure it won’t hang now for the next 10 hrs.

I’ll turn it off at night and have to go through multiple boots and hangs again the next day.

I suspect the PSU but thought i’d get a second opinion before i went out and got a new one. Do you think it could be the motherboard itself?

Specs are below:

Windows XP Professional SP3
Pentium 4 CPU 2.66GHz
1 GB RAM DDR
2x Seagate HDD (160GB IDE)
BENQ DVD writer
Creative Soundblaster 5.1 (PCI)
NVIDIA GeForce 7300GT (AGP 8X)
PSU is generic. 600W

My best guess would be the PSU.
Sounds like what my daughters computer was doing and I changed the psu and no problems since.

But take a close look at the MOBO capacitors and make sure they are not leaking and that they are not raised.Run your finger over the top and you can tell if they are.

[QUOTE=bean55;2221294]My best guess would be the PSU.
Sounds like what my daughters computer was doing and I changed the psu and no problems since.

But take a close look at the MOBO capacitors and make sure they are not leaking and that they are not raised.Run your finger over the top and you can tell if they are.[/QUOTE]

I was going to say the exact same thing :slight_smile: Please list your mobo make and model so that we can suggest a PSU if you have no problematic caps on the motherboard.

“Generic” PSUs are usually poorly made and cannot output power anywhere near their rated specifications.

Could very well be the PSU or mobo but I would try restting defaults in your bios before making any conclusions. Your Bios may have become corrupt. Unfortunatly I would not recommend re-flashing the bios if it is in fact the PSU and it hangs while flashing.

[QUOTE=crossg;2221309]Could very well be the PSU or mobo but I would try restting defaults in your bios before making any conclusions. Your Bios may have become corrupt. Unfortunatly I would not recommend re-flashing the bios if it is in fact the PSU and it hangs while flashing.[/QUOTE]
As far as I could understand from the OP, the problem vanishes once the electronics have warmed up which makes BIOS problems quite unlikely (though I would agree that flashing would be unadvisable under the current circumstances and would be unlikely to help anyway).

If it does indeed work once it is warm, I expect it is a bad solder somewhere, and warming off causes heat expansion that causes the poor connection to reconnect until it cools off again - though considering how difficult they are to test and the sheer amount of solder points in a mobo and PSU, it would be very difficult to find the exact failure point.

Also, while I agree budget PSUs are often junk, and often fail to deliver enough power, that particular PSU issue seems unlikely since it wouldn’t get better at delivering power once it has warmed up, and the problem remained even after the OP removed most HW.

While it could definately be either the motherboard, the PSU or pretty much any other device containing a PCB (printed circuit board), I’d say the motherboard is the most likely suspect, closely followed by the PSU.

Firstly, thanks to all for the inputs.

[QUOTE=Aramchek;2221321]As far as I could understand from the OP, the problem vanishes once the electronics have warmed up which makes BIOS problems quite unlikely (though I would agree that flashing would be unadvisable under the current circumstances and would be unlikely to help anyway).

If it does indeed work once it is warm, I expect it is a bad solder somewhere, and warming off causes heat expansion that causes the poor connection to reconnect until it cools off again - though considering how difficult they are to test and the sheer amount of solder points in a mobo and PSU, it would be very difficult to find the exact failure point.

Also, while I agree budget PSUs are often junk, and often fail to deliver enough power, that particular PSU issue seems unlikely since it wouldn’t get better at delivering power once it has warmed up, and the problem remained even after the OP removed most HW.

While it could definately be either the motherboard, the PSU or pretty much any other device containing a PCB (printed circuit board), I’d say the motherboard is the most likely suspect, closely followed by the PSU.[/QUOTE]

Yes the warmed up part is exactly what i’ve been thinking of. Thing is this is a pretty old PC which is why i was suspecting the Motherboard as well.
Anyway, i’m gonna get a CoolerMaster or Antec PSU in the next few days to see if that solves the issue.

Given the PC’s components, it makes more sense to buy/build a new PC if it is indeed a motherboard issue. (no SATA, no PCIe, P4 processor, DDR support only etc)

Also, there’s another thing i’m having trouble figuring out. Maybe you guys can shed some light on this:

I was preparing for exams a month ago when this problem (opening post) started showing up. I tried my best to solve it then but gave up after a week so that i could focus on studies. For the next 2 weeks, the PC remained unused. I didn’t even try to turn it on once.

After 2 weeks, I took apart all the components and checked for dust. I put it back together after cleaning out what little dust i could find. When i turned it on, it worked perfectly without any hanging. It’s been another 2 weeks since then and the problem seems to have reappeared and i know it’s gonna get worse in the next few days.

So, what do you guys think? Did this 2 weeks of inactivity somehow resolve the problem. I checked for leaky caps btw and found none. Not sure how to check for raised caps. I’ll google that to find out.

My PC may not turn on tomorrow so i’ll post an update after i install a new PSU.

What probably happened is that the location where the bad solder is got close enough to handle a connection when you removed and reinstalled whichever part the fault is in due to, for instance the board being slightly twisted, stresses being a bit different etc, after which a few heat cycles caused it to compress and expand enough for the fault to return.

I’m actually planning to build a new box myself - I’ll probably get this motherboard: GA-MA790XT-UD4P

Not sure how to check for raised caps. I’ll google that to find out.

The top of the caps should be flat if they are raised then they are going bad.

[quote=Aramchek;2221321]As far as I could understand from the OP, the problem vanishes once the electronics have warmed up which makes BIOS problems quite unlikely (though I would agree that flashing would be unadvisable under the current circumstances and would be unlikely to help anyway).

If it does indeed work once it is warm, I expect it is a bad solder somewhere, and warming off causes heat expansion that causes the poor connection to reconnect until it cools off again - though considering how difficult they are to test and the sheer amount of solder points in a mobo and PSU, it would be very difficult to find the exact failure point.

Also, while I agree budget PSUs are often junk, and often fail to deliver enough power, that particular PSU issue seems unlikely since it wouldn’t get better at delivering power once it has warmed up, and the problem remained even after the OP removed most HW.

While it could definately be either the motherboard, the PSU or pretty much any other device containing a PCB (printed circuit board), I’d say the motherboard is the most likely suspect, closely followed by the PSU.[/quote]
I read it as this so I was thinking on start up. :stuck_out_tongue: Yes it could be anything including a hard drive that is getting ready to crater. Just happened to me last week with similar results.

Thing is it even hangs if i go into the bios and let it stay on that screen.

I’ll turn it off at night and have to go through multiple boots and hangs again the next day.

Bez Do you have any type of motherboard monitoring software that you can look at the voltages, temp and fan speeds? Not sure how you could test the boot without the vid card? Has the PC ever quit and restarted or does it just hang and have to restart manually?

Update:
as expected pc refused to boot today even though PSU powered on.

I replaced it with a Tagan 600W PSU and it’s been stable for the past 4 hrs.

capacitors all seem fine on the mobo but looking into the old PSU i can see some whitish stuff on top of one of the caps. not sure if it’s leaking coz it looks more like some sort of glue/epoxy.

as for the temps and voltages, i’ve been using a prog called Hardware Sensors Monitor for a while and the voltages all seem stable as do the temps.

However, with the old PSU, i noticed that the CPU temp reported in the bios seemed to rise all the way up to 62 C prior to windows even loading. This was highly unusual as my PC idled at 50 C and only ever went beyond 60 with cpu-high operations such as encoding files or flash-intensive websites.
Fans were all fine so could it be that the old PSU was sending too much voltage to the CPU?

Anyway the new PSU seems to have fixed all that.

One question though.
I have a lot of components that use 4pin molex connectors:
2 HDDs, 1 case fans and 1 DVD writer. going to add a HDD fan soon

Is it ok to put all these on one wire?
Or should i get some SATA to molex connectors and put some of those components on the wire with SATA connectors that is lying unused atm?

Thanks to all for the help.:smiley:

capacitors all seem fine on the mobo but looking into the old PSU i can see some whitish stuff on top of one of the caps. not sure if it’s leaking coz it looks more like some sort of glue/epoxy.

Thats caps going bad.

Glad to hear that it’s running good so far.

So with the new PSU you had no trouble booting up?
And it’s been stable for 6 hours? thats great.

I have not looked into sata to molex connectors but if they have them get some . You do not want to put everything on 1 string.

Good to hear that you are up and running. It seems to me that weird and difficult to diagnose start up problems are often solved by a new PSU. I think I’ll get a spare PSU and have it around the next time one of my rigs act up. Could save a lot of time and headaches as a first test.