Repeated Motherboard failure?

[reubendiaz]

I'm working on my son's machine right now - it failed before Christmas with a popped psu which took out the motherboard also. Symptoms were - a tripped mcb on the house consumer unit and a machine which wouldn't boot/show any signs of life. When I took it apart I tested it with a good psu and found signs of life (cpu fan and hard drive started) but no inclination to boot. I tested the component cards in another machine - all good. Bought another psu (Zalman 500w) and a motherboard (Gigabyte) - had to re-install XP to stop it bluescreening, but so far so good, until it simply died again for no apparent reason. This time it is completely dead, no beeps, no sign of life whatsoever (except for the mouse diode) with a good psu - I suspect the Zalman is still OK and the board is faulty or blown.
So now I'm scratching my head - have I just been unlucky to have a faulty board, or is something else causing this problem? What could cause this? Might there be an electrical issue with the case? I have a Scythe Kama cooler on the CPU - it seems to be OK but could a CPU overheat or fault do this?

Grateful for any advice - not sure what to do next. Don't want to blow another board.

Reuben

 

[jsc]

Breadboarding the system:
http://www.tomshardware.com/forum/262730-31-breadboarding
would eliminate the case as a problem.

I'd use a known good, high quality power supply:
Corsair 550VX (41 amp 12 volt rail)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139004
or even a
Antec 500 watt BASIQ
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371004
and test it in another system first.

Then build and test in stages.

Right now, all you are trying to do is get the system to run. The stock cooler, correctly installed will be good enough.

 

[rockyjohn]

Are you using UPS or a strong power saver to protect PC?
Do you know if there are power issues in your area or have there been electircal storms?

How long did new board work before it apparently died?

I assume you have already checked the obvious - power to socket, psu turned on in back of case, power code secure?

Please provide a complete list of components.