Computer will Not Turn ON / POST

[Milly]

Specs:

Intel Pentium 4 2.0G
Asus P4S333-VM
512 DDR

Ok so this thing has been working beautifull for the past 2 years..Until today. It will not power up, I press the Power button and nothing happens. No lights, no sign of life.

So here is what i have done so far... I replaced the power supply with a new one and still the same thing.

The Green LED on the board turns ON when the power switch on the back of the PSU is flipped ON but that is it. Pressing the power button on the case will not boot turn on the computer.

So I am betting that it is either the Motherboard that is screwed or the CPU, problem is how do I tell ???? The power light on the MB turns on but that is it ....

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Now i also wanted to add the following, i grabbed the OLD power supply and hooked it up to another PC i have here, tried powering up to see if indeed that PSu was dead and it didn't power up. So for sure it is shot, the funny thing is that i placed the original power supply back and now that PC too is giving me the same problem... MB light is ON but computer it self will not turn ON. It seems to me this power supply is defiantely burning something, either the board or the CPU ...

So i have 2 pc's with the exact same problems and i just dunno what it is..

Any help would be greatfull.

 

[MikePB3]

how olds the comp?...I know you siad you had it for 2 years but did you buy it?

 

[Milly]

built it my self about 2 years ago... Don't see what that has to do with the problem anyways.....

 

[turtile]

Did you check the front panel connection to the motherboard?

 

[Milly]

Did you check the front panel connection to the motherboard?

Yes, that has definately been checked. Like i said this is happening on 2 PC's as we speak.. both same symptoms, MB light is ON but front Panel Power switch does nothing.

Both Pc's were working fine until i tried this stupid power supply which for sure caused something to fry.

Anyways i already chuked it in th garbage... When I plugged the power cable into is without havign it connected anywhere it Smoked pretty bad...

 

[Samm]

If you had this problem now on 2 different computers after the same PSU has been connected to them both, it sounds like the PSU may have damaged the motherboards.

However, this doesn't happen often in my experience, especially as the second system never even powered up once with that psu.

Try these things in the following order (do not reconnect the original psu to either system obviously at any stage, use the new one):

1. Clear the cmos using the mobo jumper & try to boot it again

2. Remove the 3v cmos battery, leave it out for 10 mins, replace & try again

3. Test the voltages coming from the old psu (while completely removed from either system)
Just cos psu doesn't power up while connected to the computer doesn't necessarily mean its totally dead - just means it ain't supplying the correct initial voltage for the mobo to trigger the mobo into switching it on.
You'll need to bridge the PS-ON pin + GND with a paper clip

4. If psu seems ok (this is not conclusive even so) then strip mobo right back to basic components (no drives, no PCI cards etc), clear cmos again & try to boot

 

[Samm]

OK, ignore most of my last post, you're latest post re. smoke etc must have appeared while I was writing mine.
Think you've probably answered you're own question in that case!

 

[Milly]

So you would bet on the Mobos being fried instead of the CPU 's ?

Just want to make sure I don't go out spend money on the Mobo's and then find out it is the CPU's

 

[Samm]

I reckon its more likely to be the motherboard. Take the board out & inspect it for any signs of a blown component. You may even be able to detect a slight burning smell if its only just happened. If not, check for any discolouration/charring etc around the components

 

[Milly]

well definately was a burn smell earlier on, but am pretty sure it was coming from the PSU...

I guess i will go out and buy a new MOBO..