On 11 Jan 2007 04:41:48 -0800, "jameshanley39@yahoo.co.uk"
<jameshanley39@yahoo.co.uk> wrote:


>ok.. I mention CPU 'cos PSU is no hassle to change.

IMO you have a mental block, a CPU is easier to change than
a PSU. You mentioned cleaning off thermal material... so
what is hard or time consuming about it? A CPU swap takes
about 5 minutes, less if you hurry or more if the case is
cramped (though similarly a cramped case makes a PSU swap a
bit more acrobatic too).



>If a POST card
>could - by telling me where the process stops - tell me if my CPU is
>causing the BIOS not to appear, then that'd help.. Could a POST card
>tell me that?

It cannot tell you the CPU is causing the bios not to
appear. It can tell you where it stops. Period. Not why.
Many board beep codes will also indicate a stopping point
that "could" occur due to an inoperable CPU... but again I
stess that CPU is not really worth thinking about unless you
had a specific reason, a direct evidence of a mechanical
problem that would obviously kill it. IOW- a lack of heat
removal. Otherwise it is not theoretically impossible for
one to fail but the odds are outside of reasonable suspicion
when starting to troubleshoot and narrow focus on suspect
parts.


>
>i'm concerned that maybe a surge caused my MBRDs to fail.

If you had alternate paths through the board, like
unprotected network equipment, perhaps. Generally a surge
into a PSU will not kill the board, the PSU itself perhaps
but it can shut off pretty quickly unless inadequately
designed.


>But, the PSUs
>are still working, and no fuse went on the plugs. So I guess having a
>surge protector wouldn't have made any difference


Fuse doesn't mean much, I get failed PSU all the time and
almost never is the fuse blown. IF the fuse were blown it
would of course be more obvious, but having it intact still
tells little.

We can only assume when you write that the PSU work, that
they are tested with an appropriate load. As an example, I
have a mATX PSU here that had it's fan fail, it had been
powering a system for about 4 years when brought to me.

System would not POST. I pulled PSU, checked voltage which
initially seemed ok and it would power on, run a load of a
couple HDDs fine. Apparently the 5VSB circuit had degraded
as the spare mATX PSU I swapped into it's place powered the
system fine. Temporarily swapped original back in just to
confirm the difference and it still showed the problem.
Eventually I may do further testing on that PSU for
curiosity's sake but that alone as the value of a 4 year old
mATX PSU is less than that of the high quality fan I would
swap in to attempt reuse, plus the higher likelihood it
would fail again since the prior fan failure had subjected
whole thing to excessive temps (for how long I've no idea
but there were portions of the PCB turning a toasted color
too).

I don't mean to suggest a POST card could never help, if you
have the post codes for these boards and plan on continuing
to test other boards eventually, it's not a bad tool to have
but most often in a situation as you're in, it is not
definitive and you'd end up having to swap a board or PSU to
isolate the variables either way.