Dead PC not PSU

[oculus]

Hi All,

I was using my PC when it just shut down. It will not start up again. No lights, no fans, nothing. I checked the power cables and the outlet, they are fine. If I unplug the PC and plug it back in and push the power button I get a very brief flash of the power light and then nothing.

I suspected a power supply failure. I purchased a new power supply and installed it and the exact same thing is happening. No lights, no fans, nothing. If I unplug it and plug it back in, I still get a breif flash of the power light and then nothing.

Any ideas on what this could be?

-t.

[JANINE]

Hi All, I was using my PC when it just shut down. It will not start up again. No lights, no fans, nothing. I checked the power cables and the outlet, they are fine. If I unplug the PC and plug it back in and push the power button I get a very brief flash of the power light and then nothing. I suspected a power supply failure. I purchased a new power supply and installed it and the exact same thing is happening. No lights, no fans, nothing. If I unplug it and plug it back in, I still get a breif flash of the power light and then nothing. Any ideas on what this could be? -t.

It could be the processor is not regulating power anymore or it could be a motherboard fault.

Reduce the system back down to barebones - i.e take out all but one stick of RAM, any expansion cards like sound, graphics, netowrk adaptors, take out all hard drives and optical drives and then see if it boots. If it doesn't boot then the motherboard and processor will both be dead - in which case you will need to buy some new ones.:)

[oculus]

Thanks for the reply.

I did as you said, stripped out everything and still nothing. Does this mean my motherboard is fried? Anyway to know for sure before I buy a new one?

Thanks,

-t.

[SnowDog]

I don't know if your machine is a branded model or a self build, but....

In our call centre we get a lot of problems with machines which either turn off (or are turned off) and then won't turn back on again.

We have the customer remove all cables, then plug in the mains cord.

If it powers up and won't POST, we book an engineer with a motherboard.

If it won't power up, we book an engineer with a PSU.

If there are any other pieces of info, like burning smells, pops, or intermittent power before no power at all, we decide whether to include either a PSU with the MOBO or a MOBO with the PSU.

In the vast majority of cases this works. I don't want to contradict Janine, but it is quite rare that we have to replace a CPU. The MOBO and/or PSU are most likely at this stage.

Is it a branded machine?

[oculus]

Thanks for the ideas Snowdog,

It is not a branded machine. I ordered it online at one of those websites that allow you to choose your own components and then they build it for you. It worked great for a year and a half.

I have unplugged everything and reseated everything and still nothing. I do not beleive it is the PSU because I've already replaced it with a new one and get the exact same results.

When it did shut down there was the faint smell of something burning, but there wasn't any smoke pouring out of the machine and no popping noises. Just the faint smell of ozone.

[SnowDog]

That's the kind of thing we look for if it's a choice between sending one or several components. But in this case, as you know the PSU is OK...

It's always tricky because there is the possibility that anything plugged into the machine could be involved. We've had rare cases where we've sent out mobos and it's turned out that, for example, the graphics card was fried. But 9 times out of 10 the mobo fixes it in a situation like yours.

One particular range of machines has a habit of burning out capacitors on the mobo and that causes the smell, it seems (in the cases I'm referring to). Smoke usually means the PSU.

[JANINE]

In the vast majority of cases this works. I don't want to contradict Janine, but it is quite rare that we have to replace a CPU. The MOBO and/or PSU are most likely at this stage.

It is a rareity for it to be the CPU and you've already replaced the PSU and reduced the system back to just barebones so it almost certainly looks as though the motherboard has failed. :)

How old is the rig? Is it still under warranty?

[oculus]

It is only about 18 months old, but unfortunately it only had a 12 month warranty. I guess it's off to get a mobo.

Thanks for all of your input.

-t.

[sg18sg18]

Any updates on this ? did the mobo sort it ?

I ask because ive got a very similar problem myself, but think mine a bit more complicated wierder :sad:

Lets say to start with my pc is running then just freezes.
only thing to do is hold power button in or reset.

Once done that when rebooting all fans and lights come on and things whire inside.

but thats where it sits, doesnt post, no messages on screen (just blank, but is lcd and normally takes a while to flick on, but not sure if that how long the pc takes to send a signal :-| )

Have tried to boot with removing things one thing at a time, untill left with just graphics card and one stick of memory, no drives what so ever, and have tried both my sticks (1gb pc3200) in all slots individually, still the same result.

NOW if i unplug the psu from the mains for a long time it will boot, but have to leave it hours, maybe days :eek: , but if i unplug psu from mains and mobo leave it a few mins pc will boot :) :-| .

Items that are new, psu, mobo.

Should state this problem started happening after i come home one day to find pc switched off and not restarting, with no lights on and found the psu fan melted and welded in place, so failed psu.

After that replaced psu and pc seemed ok, but then started doing above problem, and i noticed that the mobo wasnt reporting temps, not even in the bios, so thats when replaced the mobo.

problem still there, decided to do a reinstall on a ide drive not sata (first time it happened i thought it wasnt gonna ever switch back on but wanted info off my sata drives, and anyway in this process at one point it wouldnt switch on with a sata drive connected, but would with it disconnected, so thought that was it, but no, it then let me do a full install on my sata drive)

everything seemed to be working fine for a few days so thought the prob had gone :-| , and did some bench marking which it did ok, then i restored some clocked graphic card settings (ati x800x aiw) which had always been 100 % stable just a small increase, and then did the bench mark again and this is now the time it gone wrong again after running for a few days ok.

the new psu is a 600 w jeantech arctic, and reading in the manual of that it says about short circuit protection doing its job untill a short is cleared, now to me it sounds something like that by the way i have to unplug it from the mobo and then it will at least post and start to boot, maybe starting totally, last time it did and then i tried the bench mark again and it froze again and back to square one :sad:

so recon it gotta be pcu, ram, or graphics card, all quite expensive to guess at :sad:

but even the graphics card is only a few ,months old, ram admitedly is only cheap stuff at the momment :-|

I know all that may not make sense but hard to remember all that has happened and when, but all since my first psu died, but could it have been a fault elsewhere that fried the psu and it still present but the new psu got more protection so shuts itself down, or did the psu going down do some damage.

PLEASE help really confussed now :sad:

Thanks

Steve