Computer won't turn on - motherboard issue?

[Gorguruga]

Hi all, I have a major problem right now - my computer won't switch on. I left it running over night and by the morning it was switched off. After trying to powerup the machine, nothing happened at first. I removed the case, tried to powerup a few times and was eventually greeted by a loud bang and a brief spark was seen quite visibilly next to the fan area. The desktop speakers are powered by the power supply and seem to be functioning ok (the green light switches on) so i'm guessing that my motherboard is the culprit and needs to be replaced?

Currently I have a QDI Platinix 2 motherboard with a 1.5 ghz p4. I'm also wondering whether the P4 might have blown out too and may need replacement also?

Another major concern is this: I really want to avoid reinstalling my OS because I use my system for music and have accumulated many plugins over the years, which would take forever to reinstall. Is there a way to replace the motherboard without reinstalling the OS, perhaps by buying the identical QDI platinix mb?

Any suggestions would be appreciated right about now!

I'll check back tonight.. Thanks

 

[jeremy]

the speakers arent powered by the psu , their powered by their power cord

its defintly not the mobo , the psu died, get a new one and hope nothin happend to the other parts , it basicly depends on if the psu was cheap or not , most cheap psus will fry other parts when they fail could be the mobo/hard drive/optical drive/graphic card if its connected to the psu or even all parts except the processor , guess youll know the condition of the other parts after youll get a new one

 

[Gorguruga]

My speakers plug into the back of the psu

here's a pic of my psu:

http://www.aone.zen.co.uk/imagesproduct/psu/large/psu400cgdual300xx.jpg

Once I plug the power cord from the mains into the psu the speakers (which are already attached to the psu) will switch on. When I remove the power cord from the psu, the speakers wont work as they dont have a seperate power supply. Judging by this, I'm assuming the psu is still working although the fan doesnt spin now, but wouldnt this spin only if the computer could actually switch on? So putting all that together, is it more likely to be my mobo than the psu? Or... does the psu provide power to the speakers in a different way (as they have an external 230v socket), and its only partly functioning - the part which provides power to the rest of the pc is faulty?

 

[jeremy]

oh , first time i hear on a speaker power cord that connects there , only very old & cheap psus have that input its kinda old fashioned

lets overview the facts , you heard a loud bang then you saw sparks , means the psu died i doubt its anything else , but if you wanna be 110% sure although theres no need to in this case then do as follows

1) unplug the power cord from the psu
2) unplug the main (20/24 pin) connector from the mobo
3) use a wire thats stripped in both ends and put one end to the pin with the green wire and the other to one of the blacks

4) plug the power cord , if it wont power up then its dead but if it will then the mobo is faulty , but my guess is that it wont power up

 

[Gorguruga]

thanks for the info jeremy i followed the steps you described with a few different pieces of thin wire and the power supply doesnt power up, but Im wondering then how come the (psu powered) speakers work? The psu is only about a year old which is why I was leaning towards it being the mobo, along with the fact that the speakers work, but after these tests you could be right. Also the flash which I saw after I heard the bang was actually on the mobo, near the cpu fan, does that mean that the mobo has most likely packed up too?

 

[MrCoffee]

Can you see any obvious damage on the mobo? the only thing that would go bang is a capacitor, check your capacitors very closely for leaks etc.
If it is a capacitor you can replace it with a new one and if you're lucky everything should be ok.

Does the fan in the PSU spin up when you power on the PC?

 

[Gorguruga]

Theres one capicitor in the mobo which looks like its rusted on the silver surface, and its basically in the same area where the mini-explosion took place. Could I replace this part myself? Is it a simple soldering job?

And no, the fan on the PSU doesnt spin up when I try to power up the pc, the power light doesnt light up on the pc either.

however the power light on the speakers does light up and they get their power from an external 230v socket on the psu so I'm not too sure if its the PSU, mobo or both?

 

[jeremy]

thanks for the info jeremy i followed the steps you described with a few different pieces of thin wire and the power supply doesnt power up, but Im wondering then how come the (psu powered) speakers work? The psu is only about a year old which is why I was leaning towards it being the mobo, along with the fact that the speakers work, but after these tests you could be right.

you welcome , if im not mistaking the main input & the other the speakers connect to are linked via wires and the power is just being shared between em, it aint powered by the psu itself , anyway you tried to "hotwire" it as suggested and that didnt work so its defintly dead

Theres one capicitor in the mobo which looks like its rusted on the silver surface, and its basically in the same area where the mini-explosion took place. Could I replace this part myself? Is it a simple soldering job?

first of if you dont have much expirence with soldering your better off having it replaced at some electronic repair shop , but if you do have expirence then i guess you can replace it yourself , naturally youll need to get a capacitor with same specs , i wouldnt say its simple
http://www.tmo.com/howto/ecu1g/caps.htm
http://www.overclockers.com/tips1081/

 

[MrCoffee]

Hmm sounds like a bad capacitor:

Examples

More

even more

Are you sure you can get the PSU to spinup by shorting as jeremy sugested? if not then you'll need to replace that too.