HELP!! PC powering off randomly, at random times, for no reason!

**fishsponge** · June 23rd, 2003, 06:34 PM

Hello...

My computer keeps powering off for no apparent reason whatsoever, it seems. This obviously isn't the case, but i don't know what the reason is.

Anyway... here are my symptoms...

There are actually 2 issues i'm experiencing... 1. The machine instantly powers off, without warning, and with no errors or beeps. It then powers on again fine, once i've taken the power lead out and put it back in again. 2. The monitor goes black, and loses the signal from the graphics card, but the fans continue to run, and everything is powered up. I then have to manually power it down, and restart it.
Sometimes runs faultlessly for hours and hours.
Sometimes runs for about 5-10 minutes and then shuts down.
Temperatures are fine: CPU - 50 C, Case - 39 C.
1 week ago, it powered off at 2:30pm while i was at work, on a really hot day, and wouldn't power up again. I got brand new 400W PSU. The only items plugged into PSU are motherboard, HDD, FDD and 48x CD-RW and one case fan.
It runs perfectly for as long as it wants as long as i don't use it.
I use up 100% of idle processor time with DNET, so CPU usage isn't an issue.
It does seem to poweroff more when i'm using graphics intensive executables (Colin McRae Rally 2.0, Driver etc...). Occasionally though (about 10-15% of the time) it simply loses the signal from the graphics card instead though.

So... my conclusion is that this problem is not related to temperature, power consumption, PSU faults, cable problems or wall socket polarity (i'm in the UK).

I'm tempted towards saying it's a graphics card issue, but the same graphics card, with the same motherboard, with the same PSU, same HDD, same CD-RW, same sound card, same USB card and devices, same mouse, same keyboard, same case, same monitor, same drivers and operating system installation have all worked together *perfectly* since Christmas!!

Any ideas people?? i'm really confused, and this is getting to be a bit of a pain, lol

thanks in advance

**Eraserhead** · June 23rd, 2003, 07:22 PM

Could be a graphics card problem. Try using a different card if you can get hold of one, see if it makes any difference

**vanik** · June 23rd, 2003, 07:40 PM

Ugh I have the EXACT same problem.. its on my thread in the main page too

Just to offer some insight, I had a nvidia TNT and changed it to a geforce fx and it still had the same problem.. it might not be the gfx card

**nurdonsite2** · June 23rd, 2003, 08:32 PM

did this just suddenly started to happen? or did u install some new hardware or made some other physical change to the machine before this started to happen?

**Omardeth** · June 23rd, 2003, 08:39 PM

to me this sounds like classic power supply going out . random reboots are either a heat issue or power supply dieing most of the time . if you can try replacing the power supply . i would recomend a 400w or better . but this sound like the power supply is going . you said it will be fine but you noticed that if you do something that the grafic card is being used with it will reboot . well when the grafic card goes to do 3d it will pull more power than 2d . boom it reboots .

question when wa sthe last time you blow out the case with caned air ? dust build up can make the power supply work harder than it would normaly and also it holds heat in .

hope this helps

**pickel** · June 23rd, 2003, 10:01 PM

Make sure you have a good ground at the power receptical. Also check for a loose neutral wire. Intermittant power surges can cause all kinds of funny things.

**fishsponge** · June 24th, 2003, 02:48 AM

Originally posted by Eraserhead
Could be a graphics card problem. Try using a different card if you can get hold of one, see if it makes any difference

as you can see though, i have had the *exact* same hardware configuration since Christmas, with the exception of the PSU that broke 2 weeks ago. Also, vanik is having this exact same problem, and he's already tried replacing the graphics card.

Originally posted by nurdonsite2
did this just suddenly started to happen? or did u install some new hardware or made some other physical change to the machine before this started to happen?

ok... what happened was this... My machine was running perfectly without a problem or a care in the world since Christmas, until a really hot day last week. The PSU broke at 2:30pm on this hot day, so i got a replacement (as it's under warranty). I fitted the new PSU, and now these issues are occuring. that's all i've changed.

Originally posted by Omardeth
to me this sounds like classic power supply going out . random reboots are either a heat issue or power supply dieing most of the time . if you can try replacing the power supply . i would recomend a 400w or better.

ah... but it's a brand new PSU. it's 400W as well.

Originally posted by Omardeth
...but this sound like the power supply is going . you said it will be fine but you noticed that if you do something that the grafic card is being used with it will reboot . well when the grafic card goes to do 3d it will pull more power than 2d . boom it reboots .

true... but it's a 400W PSU that i currently have in there (i also had a 400W one before it broke). I hardly have anything plugged into the PSU, so why should it be pulling too much power?

Originally posted by Omardeth
question when wa sthe last time you blow out the case with caned air ? dust build up can make the power supply work harder than it would normaly and also it holds heat in .

in my original post, i said it's a brand new PSU, so there's no dust whatsoever. none inside the case either.

strange problem eh??

**Omardeth** · June 24th, 2003, 03:21 AM

i still think it is a power supply problem . because the supply says it is 400W doesn't really mean anything . it can be a 400w power supply that only puts out 11A on the +12 volt rail . if this is the case it is under powered . look on the side of the power supply it will list it like this .this is from a 400w power supply

+3.3V -> 20A Orange
+5.0V -> 40A Red
+12V -> 12A Yellow
+5VSB -> 2A Purple
-5V -> 0.5A White
-12V -> 0.8A Blue

see how this power supply has only 12a on the =12v rail ? that is borderline for todays systems .

here is another 400w power supply
Orange - +3.3V 28A
Red - +5V 35A
White - -5V 0.5A
Yellow - +12V 15A
Blue - -12V 0.8A
Purple - +5V Standby 2.0A
as you can see they are both 400w but have different specs .

i just rma'd a antec tru550 power supply . i was having the same problem random reboots , lost drivers , total system crashes . i tried everything because i didn't want to believe that the 110$ i spent 6 month earlier for the power supply was the problem . well after trying everything i could think of i switched out the power supply with one i had here i was going to put into another pc . and the problem stoped .... you don't give the full specs on your pc and you don't give the specs on the power supply but from what you are saying i would still blame the power supply . now you don't need to go get a bigger supply . 400w is a good type to get . you just have to make sure the "rails" are high anuff to support all the things in your pc . this might be a good read for ya http://www4.tomshardware.com/howto/20021021/index.html

RicheemxX · June 24th, 2003, 03:33 AM

IMO from what i read I don't see why anyone thinks its a psu problem...maybe an overheating psu...but not a bad one. Your cpu temps are a little on the high side but no higher than mine. As for compariing your problems to someone else thats allright for some ideas to look at and possible suggestions but ruling something out because it did or didn't fix his problem just doesn't work. Two computers with identical everything can still have seperate reactions to things.

I'd say its either A} your psu is overheating or you got a bad one from the rma B} your video card is overheating. C} your cpu fan might be part of the problem as well not sending a constant signal to the mobo and causing it to shutoff

Is that p/s the same exact make/model as the one before?? you can never rule out what omar said...

edit:damn fingers adding in those typos all the time

**vanik** · June 24th, 2003, 02:02 PM

Just bought a new 400W power supply at the local comp store and still got the same problem

So I guess it's either a motherboard, cpu, or ram problem.. thats the only things that are left...

**Omardeth** · June 24th, 2003, 05:35 PM

what are the specs on the power supply can you list them please .

**RedFury** · June 24th, 2003, 11:40 PM

My first thought was the power supply also, but here are some suggestions, just to make sure everything is proper. Reseat all your cards, watch the CPU fan ( run with the side off if necessary ) to make sure it stays running without any weird hiccups.

My old IBM used to just power off for no good reason too. I had installed a voodoo 3 3000 and thought that it was running to hot and causing an overheat reboot...until I installed a faster processor and underclocked it ( because the mobo couldn't run it at full speed ). It'll run all day long now without issue.

One more thing, are you running on a surge protector or not?

**fishsponge** · June 25th, 2003, 04:24 AM

Originally posted by Omardeth
what are the specs on the power supply can you list them please .

yeah... i found them out when i went home last nite...

...and here's my PCAlert status...

Originally posted by RedFury
My first thought was the power supply also, but here are some suggestions, just to make sure everything is proper. Reseat all your cards, watch the CPU fan ( run with the side off if necessary ) to make sure it stays running without any weird hiccups.

My old IBM used to just power off for no good reason too. I had installed a voodoo 3 3000 and thought that it was running to hot and causing an overheat reboot...until I installed a faster processor and underclocked it ( because the mobo couldn't run it at full speed ). It'll run all day long now without issue.

One more thing, are you running on a surge protector or not?

I already re-sat all my cards and cables, i run with the side off anyhow, and all the fans (including CPU fan) run faultlessly all the time.

As for it running too hot, this isn't an issue... i have the BIOS set to the lowest possible cutoff temperature, which is 70 degrees C. my CPU is considerably below that, as you can see.

...and yes, i have it plugged into a surge protector. the surge protector is then plugged into an RCD trip switch.

**fishsponge** · June 26th, 2003, 10:43 AM

ok... here's an update... this is getting weirder.

my machine has now been "up" for about a day and a half non-stop! ...but all i've done is check my email, visit a few web sites, browse through Explorer, burn a couple of CDs, download a few MP3s, and listened to the MP3s too.

This all worked fine.

I then loaded a nice game - Driver. I went through the menus, loaded a game, and began driving. about 5 seconds later, the graphics skipped, and then about 2 seconds after that my machine instantly powered off. I pulled the power lead, put it back in, and it rebooted fine, and continued to work fine for another 2 hours (i didn't play the game after this).

I was then using Kazaa, and my monitor went black (it had lost the signal), and i couldn't do anything. i was listening to music at the time and the sound card was continually outputting one frequency of noise (the last thing in it's buffer). the machine stayed powered up though.

unfortunately, i had to power it off anyway, in order to reboot it, but this is a very weird problem.

any ideas????? aarrgghh!!! lol

**nurdonsite2** · June 26th, 2003, 10:46 AM

i also think is the PSU. try to return this one and get another one.

**fishsponge** · June 26th, 2003, 10:58 AM

but what are your reasons for thinking that it's the PSU exactly??

it runs faultlessly while i'm listening to music, downloading stuff, and burning CDs simultaneously (usually), but as soon as i started playing Driver it powered off. My CPU gets used at 100% permanently anyway, so it's not that drawing too much power either...

why do you think it's the PSU as well??

thanks for the advice btw

**pjaj** · June 27th, 2003, 04:48 AM

I'm also dubious that it is the power supply. See my post to vanik's almost identical thread in this forum.
I've got one old box with a marginal supply (250W) and a new one with an Enermax 465W and that has a maximum loading of 35A on the +12V rail.
What OS & software are people running?
I'm using W2K Pro and a mixture of Photoshop 7, Dreamweaver MX, Office mostly.
The only games I play are patience (various) and Snood (don't ask!)
Now I believe that some of you have said that you run mostly games, so it isn't the primary applications that could be causing it, but what about all those things that think they are so indispensible that load a startup? Real Player, WinZip, Creative's utilities, Norton / Sighmantic

etc.
In my case the PC can be completely idle when it reboots.

**Omardeth** · June 27th, 2003, 05:13 AM

if you look at the power supply you will see the max output on your +12v is 12a ... the one marked yellow . if you look at the amd sight they recomend min 14a on the +12v rail . you said it was fine till you try to run a game . well when you run the game the video card really starts to pull on the power supply . when that happens the system will freeze or reboot . find yourself a power supply with at least 15-16a on the +12v it should be marked on any power supply you get . i would bet you get one with that spec you will have no more problems . it doesn't matter so much how many watts it is sometimes . that throws alot of people off . here is an example of some nice specs for a power supply .

hope this helps

**nomaxim** · June 27th, 2003, 05:21 AM

Just something of the wall but, is there anything else on the house circuit?

Is the outlet(s) being used by anything else? ie. Frig, A/C, TV, anything like that.

**Omardeth** · June 27th, 2003, 05:25 AM

i don't think it is that nomaxim , i really think the +12v rail just doesn't put out anuff juice .

you don't list full specs on your pc so i don't know whats in it to figure out how many amps you pull . but you might want to go read this link it is a nice write up on power supplies . on the 3rd page it shows a list of was a game pc pulls on each rail , rememebr it isn't exact each device will pull more or less depending on the device but it will give u a good idea . a basic system with an amd cpu pulls over 12 amps alone . and thats with hard drive, cpu , dvd, burner, 1 cpu fan and 1 system fan (they are the only things pulling on 12v rail ). and for instance lets say you have a volcano 9 heatsink fan . it can pull up to .5a alone . the list on that link only rates a cpu fan for .25a . so my guess is the system doesn't get anuff amperage when you run the video card . the cpu don't get the juice , it reboots . make sence ?

hope i helped