[GTALUG] [OT] Dead motherboard or dead CPU?

[Lennart Sorensen]

On Thu, Nov 20, 2014 at 06:41:38PM -0500, Kevin Cozens wrote:
> Greetings, all.
> 
> Someone recently reported a problem booting their computer. I've had
> my first ever major failure of a system where I can't boot my
> machine. My situation is a little different than in the previous
> thread about a boot problem. FYI, my machine is an HP m7680n with an
> Intel Core 2 Duo CPU that I have had for several years and gets a
> lot of use every day.
> 
> When the machine powers up all the fans start spinning and the
> drives do their initial power on reset activities. The CPU doesn't
> seem to warm up AFAICT (unless I haven't let the system run long
> enough for it to warm up).
> 
> The first time I had a problem starting up the system I power cycled
> the machine a few times and got it to boot. I did that on three
> consecutive days but starting with the fourth day power cycling the
> machine is no longer able to kick the machine in to showing signs of
> life.
> 
> A POST card shows ---- instead of any actual code. All the LEDs on
> the POST card light that are related to power supply voltages. CLK
> is also lit up and the RESET LED comes on briefly at power up and
> power down. The IRDY and FRAME lights are always off.
> 
> I have tried to boot after pulling all plug-in cards and even after
> also pulling the RAM and disconnecting the SATA drives. The power
> supply is a Corsair TX650M that is only a few months old. The
> separate four pin 12V connector to the MB is reading within
> tolerance.
> 
> There are no signs of bad capacitors on the MB (ie. none that have
> bulges on the top). I don't have an ESR meter to propery test the
> individual capacitors.
> 
> Am I looking at a motherboard failure or is it possible the CPU has
> died? I read the C2D is quite reliable so CPU failure seems less
> likely than an MB failure but anything is possible when dealing with
> electronics.

Well short of swapping parts it can be hard to determine the problem.
Could be motherboard, power supply, CPU, ram, video card (if not onboard).

-- 
Len Sorensen