2 weird hardware problems

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1) A PC i've just built ot of an old mobo.

Boots up fine into the BIOS Screen, Bios shows a checksum error,
change a few options like boot sequence, and save & exit, then PC
refuses to reboot into BIOS screen. Powers on, but does not initialise

Clear CMOS and repeat, same thing, boots into BIOS screen.

What does the assembled think Dodgy CMOS battery ? Board is an ABIT
KT7 Raid

2) Sony Vaio laptop. Had to disassemble to desolder and replace the
dodgy power plug on the mainboard, but now it is back together, it has
the symptoms of having the power switch depresssed all the time, i.e
you shut it down and it immediately powers itself up and reboots. On
powering the laptop for the first time, you need to press the power
switch to turn on.

So in summary, press power switch to power on, shut down or hibernate
and it does not power off, only restarts.



Re: 2 weird hardware problems

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You know CMOS batteries eventually wear out and you
do not know the age of this battery except that it is "old."
So your hypothesis is likely i.e. can be tested for about $3 for
a new CMOS battery.

Don Phillipson
Carlsbad Springs
(Ottawa, Canada)

Re: 2 weird hardware problems

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Nope, not CMOS battery, PSU or VGA card.

Suspecting knackered BIOS chip currently ..


Re: 2 weird hardware problems

On Thu, 3 Jul 2008 15:44:00 -0700 (PDT),
zymurgy@technologist.com wrote:

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First, remove battery and disconnect AC power for 10
minutes.  Also use clear CMOS jumper just for the heck of it
to be thorough, then after the 10 minutes restore the AC

If/when bios shows checksum error, enter the bios and save
it, not changing any settings yet.  See if system then
restarts or not.  If it does not restart you probably have a
situation where the bios was first loading failsafe defaults
but was trying to load correct settings on subsequent
attemps.  This could be a problem in several ways, like if
the PSU is not capable of enough current at the potentially
faster processor speed ran upon 2nd and thereafter boots, or
more commonly if there is a memory compatibility or other
stability problem.  Thus, try removing all but one memory
module for the time being, and try different memory if you
have some.

I doubt the bios chip itself is "knackered", though what you
might do is put memtest86+ on a bootable device, hopefully
something the bios can boot from as a default device and see
if you can coax the system to boot to this... if the former
speculation about loading settings on subsequent boots is
the problem you might try manually setting the most
conservative settings possible - not necessarily what the
parts dictate based on their spec but instead slightly
higher voltage, lower FSB and memory bus speeds, more
conservative (higher) memory timings.

If you can get the board to stabily boot to memtest86+ and
it shows errors, replace memory or change bios settings.  If
it doesn't show errors, put the bios image on a bootable
drive and flash it... the flasher should read and confirm a
proper flash has happened, and just maybe a newer bios would
resolve some unforseen problem or memory compatibility.

You haven't told us about the other parts in the system such
as which CPU.  Being an older board it might not be very
suitable for newer more current hungry lower voltage
processors like the later generations of Athlon XP.

As for the laptop, hard to say.  Open it up and inspect the
assembly, perhaps there is some gunk under the on button or
a broken spring or membrane, a lid switch or cable problem,

Re: 2 weird hardware problems

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<Snip useful advice>

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I was given an old server board out of a working system (though the
system was working 'some time back')

It came complete with installed RAM & CPU that had been ok as a

Reseated everything, and coupled it with a 350w PSU.

Everything powers on ok, apart from the CMOS checksum error.

I've faffed with it long enough now I think, for what is essentially
an old piece of clag even if I do get it working.

I'll pass it on to someone who can be bothered trying to re-flash the
BIOS, or they can cannibalise the RAM, HSF and CPU off it. (RAM is old
PC133 stuff)



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