HELP [weird problem] pc shuts down after 2 seconds!!!

[king_koopa]

i have this really wierd problem which i think has something to do with my power supply but im not sure

when i turn on my computer, after about 2 seconds it switches off!!
then if i press the power button again nothing happens!
then if i turn off the power from the powerpoint then wait about 5 seconds turn it back on then switch on the computer it does the same thing (boots for 2 seconds then switches off)
if i turn off the power from the power point for about 1 or 2 seconds then switch it back on and then press my power on button, nothing happens. it will only boot if i leave it off for about 5 seconds or more.

i kept going through this but then i found a sort of solution, i turn the computer on then after it turns itself off i unplug the two main power cords that connect into the psu then plug them back in and then it boots perfectly normal!!!

so as you can see it is very weird

EXTRA INFO:

my pc is not too old, its a p4 3.2 with a 400watt psu.

the monitor and the pc are connected to a power board which cost around $25 and has surge protection, also connected to that is a desk lamp and a printer.

Also sometimes it just switches off while i'm using it and i begin having the same problems turning it back on

*******************

thanx heaps if someone helps me out!!!!!!!!!
if u want any additional info just let me know!!

thanx heaps in advance!

[azzey]

Hello, and welcome to the PC Guide forums! (hehe... I gotcha first http://www.pcguide.com/ubb/biggrin.gif)

Sounds like a thermal problem to me. Whenever a computer just 'turns off' suddenly, it generally points to a temperature problem. Are you doing anything intensive before it shuts off?

During the 2 seconds that it does turn on, check to make sure that your CPU heatsink fan is spinning. Nearly all motherboards will cut the power if the fan isn't spinning to prevent damage to the CPU.

See if you can check your CPU and motherboard temperatures.

Oh, also post your system specs if you can. Your computer isn't that old... I'm still waiting to upgrade from a P4 2.6 ghz system to an Athlon 64 3500!

[Whyzman]

Welcome tohttp://www.pcguide.com/ubb/pcgubb.gif Forums!

I'm wondering if there might be a problem with the processor's fan. Newer motherboards have an RPM sensor that will shut it down immediately if adequate RPMs are not achieved.

If the fan is having a problem it could also be stopping or slowing down while you are using it and that would either result in the CPU heating up and shutting down, or the RPM sensor shutting it down...

You might want to pull the case or side and keep an eye on the fan...

[edit] Wow azzey, this is the second time I've been beat today...I need to use more than 2 fingers for typing I can see... :)

[king_koopa]

ok thanx heaps for the reply, your a legend!!

i had a suspicion this could be the case, but heating doesnt explain how when i took out the two plugs at the back then put them in it worked

and what about how after it turns off, i keep on clicking the power button but nothing happens until i switch it off then back on from the power point??

AND - a very interesting note - when ever i start running programs which use a lot of memory and whatnot, a very loud fan noise comes on, i think that a fan speeds up. i dont know which fan though, either the cpu or the psu. it is a very annoying noise and i think it is set to come on at a certain temperature or something.

also the fan at the back of the psu doesnt seem like it is doing much, cause not too much air comes out of it. the fan that i put in under it which cost like $15, emits way more air!!! this could be cause it is the fan that is set to a temperature, but im not sure.

Yeah my specs are:

P4 3.2ghz Hyper threading, lga 775 socket
Motherboard is gigabyte (i think) with agp 8, 865pe chipset
200 gig hard drive
1 gig ram
windows xp pro (sp 2)
ati radeon 9600 pro 256 mb (i think)

im gonna turn off my pc and check if the fan spins or not

[king_koopa]

yeah thanx for the other reply, i will check

but how do i check the cpu speed??
and rpm for the fan???

[Whyzman]

What you may need to do is perform your special way of getting it to turn on...and then, watch the fan while it is running. Might be good to see if you can actually hear which fan is making all the racket...

[king_koopa]

alright i got a few other theories

it is the cpu fan that is making all that noise!!
it keeps on speeding up and speeding down, and it is extremely loud when it speeds up!!!

it is the fan that came with the cpu, should it be doing this???
and when i'm in a game it is always constantly sped up and the noise is so loud!!
so is this normal???

Theory 2: i added in two fans and a pci slot fan to the pc, is this too much for the psu to handle?? remember it is 400 watts running all the fans and 3.2 HT cpu.

[king_koopa]

alright for now, it is booting up fine, so i cant check to see if the fan is spinning or not (it will probably stop booting up tomorrow though) and when it does turn off i can hear a sort of faint beep (as it turns off). one that isnt loud or high pitch, could this be the fan sensor or whatever?

[Whyzman]

When a computer makes it through the POST (Power On Self Test) there is normally a faint single beep.

What size fan is currently on the heatsink? Many of today's fans are sensor controlled so they don't need to run full throttle all the time. As the CPU heats up, especially during game play where demands are heavy, the fan speed will increase. The smaller fans are noticeably louder than larger fans...there's some sort of direct relationship to fan speed and decible levels.

Larger fans don't have to turn as fast to move an equivalent amount of air as the smaller fans. That being said, you might want to consider a larger fan since it appears that the current one is a problem child...

Would you let us know the size of your CPU fan?

[king_koopa]

alright i will check, but im busy now, in about 3 hours i'll post it up

thanx hapes for all ur help

[king_koopa]

ok just found something out,

i checked the cpu temp and it was 64 degrees!!! so i think i might need a new fan
and the fan is about 9cm diameter and spins when going very noisy and annoying at 3,443 rpm

so, that changes things a bit dont it

[king_koopa]

alright this morning it wouldnt boot up so i was able to check whether the fan was working or not and it was!
so i dont know what that means, but i dont think it is overheating because how come it doesnt boot up in the morning??? cause i turn it off overnight??
it seems to be when it is off for a long period of time, it wont boot up again

also could it be the psu fan not starting up at boot?? would this also cause the pc to shut off???

[king_koopa]

so why do after i turn off the power from the powerpoint have to wait like 3 seconds before i turn it on again so that it will turn on???

if i turn it off then back on in like one sec the pc wont turn on!

plz someone reply quickly!! its doing it to me every day!

[hockey man]

New pc are smart enough that if a fan is not working, it won't boot. If your PSU fan is going, that might be your problem. Also, have you opend up your case and checked for dust?

[jlreich]

From your first post.
when i turn on my computer, after about 2 seconds it switches off!!
then if i press the power button again nothing happens!
then if i turn off the power from the powerpoint then wait about 5 seconds turn it back on then switch on the computer it does the same thing (boots for 2 seconds then switches off)
if i turn off the power from the power point for about 1 or 2 seconds then switch it back on and then press my power on button, nothing happens. it will only boot if i leave it off for about 5 seconds or more.
By "powerpoint" you mean the rocker switch on the back of the power supply?

If that is so, then this points to the power supply being bad. Either the fan on the power supply isn't working correctly or there is something else not functioning right inside the PSU that is causing the internal fuse on the PSU to trigger off.

When the fuse is triggered you have to turn off the PSU for a few seconds or so using the rocker switch in order for it to reset or the system will not power up. Which is what you are describing.

If you can, try a known good PSU. You can try blowing out the PSU fan with a can of compressed air to see if it will free up the fan if dirt is the problem. But it could also be the bearings going bad in the fan as well. It isn't good at all for the computer to suddenly loose power like that, and their are no serviceable parts in a PSU unless you really know what you are doing. I would start shopping for a new PSU. ;)

[king_koopa]

alright thanks for the replies. the psu fan goes but it isnt very powerful
as i said before, i put in a $15 flexiglow fan and it blows heaps more air than the psu fan (is this normal??????) i think the psu fan might be running slow!

and about the dust
there is HEAPS of dust caught in the cpu heatsink!!! i mean heaps, but i dont exactly know how to take off the fan and heatsink so i can clean it.

about the switch i was talking about, it isnt the rocker switch as my psu doesnt have one. ist an omni 400watt switching power supply. i was talking about from the powerpoint on the wall, but this would do the same thaing as the rocker switch would soi think you are right!
also i if i take out the plug in the back of the psu (the one hooked up to a powerboard which is hooked up to the powerpoint in the wall) then put it back in AFTER about 5 seconds it turns on again (for about 2 seconds)

also i noticed today that everytime it turns on for about 2 seconds, the time always varies from about 1 to 2 seconds!!

so yeah thanks heaps for the replies!!! so do you think the power supply is the problem???
if i were to buy a new one, how many watts should i get?

[Whyzman]

Sounds like your computer needs a thorough cleaning! Many of the problems you describe could be symptoms of dust accummulation on not only the heatsink, but also dust laden fans and innards.

When cleaning, you need to be aware of ESD (Electro Static Discharge) which can fry components. I would suggest buying a couple of cans of compressed air, the type used for such cleanings...if the dust is caked on as you mention...it will create a hailstorm of dust...you might want to bring the rig outside for this...

You may not need to remove the fan and heatsink. The compressed air may be able to dislodge the gunk...

[king_koopa]

yeah i got most of the dust away

but it still is creating problems, so i think im gonna buy a new psu and see what happens

[king_koopa]

alright i found out what causes it to power off suddenly when i'm using it
its when i put a cd in
i put one in and it powered off straight away, then when i got it back on and tried to acces the cd it powered off again!
so im guessing the psu doesnt have enough power to power the cd drive???
or is it the cd drive that is causing all of the troubles????

thanx heaps if anyone replies

[king_koopa]

I got a new PSU and now everything works fine!!

tahnx everyone who replied! i really appreciate the help!

[jlreich]

Glad to hear it. Thanks for posting back what fixed it. :)

[Whyzman]

Yes, thanks for posting back with your solution. It sure was showing positive signs that the PSU was the culprit...Glad your up and running! :)