Dead CPU or MOBO ???

paul&nat

Hi im trying to find a problem on a comp i have -

When i plug the comp into the mains and switch it on at the PSU all that works is the green light on the power switch, internal fan (attacted to back of case) and the psu fan.

When i press the power button nothing happends at all, no beeps, no cpu fan, cant open cd drives, cant hear hd powering up.

I have tried unconnecting everthing one by one (memory,nic etc) and it makes no diffrence at all. I have tried the motherboard in another case and the same happens. i have tried placing the mobo just on the antistatic packaging it came with and powering. I dont have spare mobo's or cpus to eliminate one or the other.

Does anyone know if it is the motherboard or cpu ??

Thanks

Paul

wolfman

Most likely the Motherboard, although don't take my word for that. All power goes via the mobo, so if nothing is happening it'll either be that or the power supply. I wouldn't think it'd be the cpu just yet, you can have a bad cpu, but still get the computer to power on, it'll just give an error beep code to indicate something is wrong with the cpu if that was the case.

intel

It still may well be the PSU reason I say this is my Brother had the exact same problem and it did indeed turn out to be the PSU

paul&nat

I Have just replaced the PSu witha brand new one and still getting the same problemo!
and i tried reseating the cpu, had a quick sniff didnt smell burnt out he he. The comp is only about 3 year old.
Is there no way of finding out unless i try alernative cpu or mobo ??

thanks for the replys

Paul

T4i

Quite hard to tell what is the problem if you have no spare parts to try. I'd say its your motherboard.

T4i

and like Intel has said the PSU maybe new but it could have had a fault. The 12v rail might be working but other rails may be damaged.

paul&nat

Do you think it will be ok to try the psu in this comp ?? i mean will there be a chance it could damage this mobo ??

wolfman

Does sound more likely to be the motherboard. If the new psu definitely works (ie was tried in another machine) then I'd be quite certain it was the mobo.

The only way you can really find out is to switch it with a motherboard you know that works. My dad had the same problem a year or so ago, but it's never easy finding someone who'll spend the time to take out their mobo, and find one that's compatible with what you have.

In the end he just bit the bullet and bought a new one, and it turned out it was the mobo. I'd make sure you know the psu definitely works before considering buying a new mobo.

paul&nat

right i have just tried the brand new PSU in this machine and everything was fine. So do you all think it is the mobo ?? or could it still be the CPU ??

Thanks again

Paul

T4i

mobo. very unlikely to be the CPU cas the mobo should still power up with a damaged CPU.....it should just bleep like mad.

Have a look at the capacitors on the mobo, the ones nearest the RAM/CPU. Do they seem to have bulged caps?

paul&nat

no T4i they look ok (not bulged) a couple look a bit disfigured but not bulged. what would that mean if they were out of intrest ???

I better start pricing up ne MOBO's by the looks of things !!!!

Paul