On 11 Jan 2007 01:41:24 -0800, "jameshanley39@yahoo.co.uk"
<jameshanley39@yahoo.co.uk> wrote:


>thanks I guess the POST cards aren't so useful to me 'cos a beeping
>computer is a doddle to diagnose anyway. I don't have so many beeping
>computers to make it that useful. And if there' no BIOS booting then I
>can see. No need for a code to say so ..
>
>But what interests me is 2 MBRDs with te same problem. They power on
>but don't boot the BIOS.. i'm wondering if it could have a common cause
>,, common electrical problem. Or even the same problem on the MBRD, in
>which case I may be able to be more informed and avoid it next time(if
>it's the same problem), 'cos maybe there are some models that don't
>have it, or maybe some device caused it. And it's good to know
>anyway... How many common causes are there to have that effect? Is it
>a really standard MBRD failure?

No, a failure to POST is an extremely common generic
classification that could have far too many causes to list.
While it is possible both boards have the same problem (and
odds of this might go up if the boards were virtually
identical), it isn't reasonable to assume without far more
evidence.

>
>And would a POST card help with telling me if the reason it won't boot
>is CPU ? 'cos I hate replacing that, that would save time if it could
>do that. Though I don't get any beeps, it's not POSTing - how can it
>without a CPU.. So maybe it never beeps when no CPU? I don't know.

A BIOS follows a sequence, and the post card tells you where
in the sequence it stops, but not what caused it to stop.
Therein lies the problem, a POST code can't tell you of many
of the most common board failures like a corrupt bios,
capacitor or other discrete component failure, physical
stress like cold solder joints, board cracks, tin whisker
shorts, ESD damage, etc, etc.

Because of the complexity of any semi-modern motherboard,
not much time can be spent effectively on single boards
failing. It works or it doesn't and if a fault isn't
visibly obvious (like vented capacitors or a burn mark on a
chip, knocked off resistor or something similar) there is
hardly a reasonable return from time it would take, let
alone the equipment it might as well.

FWIW, unless the system ran long term with a failed fan or
the heatsink fell off entirely while it was running (or an
attempt to start it, running merely means power applied, not
necessarily running the OS), it is far less likely the CPU
than motherboard. PSU might be 2nd most common... if you
had two identical systems (or PSU) the PSU might rise to
position of prime suspect, particularly if generic or other
retail/aftermarket came-with-case PSU.