HELP: (un)dead motherboard

  • Thread starter Thread starter Stylus
  • Start date Start date
S

Stylus

Hi peeps,

I replaced a faulty-ish N-Force 2 mobo + Athlon XP combo in a friend's
computer. Inspecting it there was some 'rust powder'-like stuff next
to the serial/parallel/USB block, over SMD resistors. Spraying it with
compressed air removed it completely, and nothing seems blown or
physically damaged.

Basically if the board stays unpowered for a day or so it boots fine -
the first time. Windows loads and works, etc. Subsequent warm boots
are fine too.

On the next cold boot the fans start but screen stays black. No BIOS
beeps, etc. On the next day the board boots again - maybe.

CMOS-clearing might (I'm not certain) helps that first boot, but is
useless afterwards. Swapping ram and VGA shows that the problem is in
the CPU or mobo. I'd guess 99% mobo, at this point. (Dead Athlons
don't power up once in a blue moon, do they?).

Is there anything I can check (capacitors etc) and try to fix before
trashing it for good? Damn, there's few things I hate more than those
voodoo 'on the brink of working but not there' situations ...

TIA
 
Stylus said:
Hi peeps,

I replaced a faulty-ish N-Force 2 mobo + Athlon XP combo in a friend's
computer. Inspecting it there was some 'rust powder'-like stuff next
to the serial/parallel/USB block, over SMD resistors. Spraying it with
compressed air removed it completely, and nothing seems blown or
physically damaged.

Basically if the board stays unpowered for a day or so it boots fine -
the first time. Windows loads and works, etc. Subsequent warm boots
are fine too.

On the next cold boot the fans start but screen stays black. No BIOS
beeps, etc. On the next day the board boots again - maybe.

CMOS-clearing might (I'm not certain) helps that first boot, but is
useless afterwards. Swapping ram and VGA shows that the problem is in
the CPU or mobo. I'd guess 99% mobo, at this point. (Dead Athlons
don't power up once in a blue moon, do they?).

Is there anything I can check (capacitors etc) and try to fix before
trashing it for good? Damn, there's few things I hate more than those
voodoo 'on the brink of working but not there' situations ...

TIA
Click to expand...
In cases like this I have found that 70% of the time it is the PSU not
delivering enough power on one of its lines, normally the 5v.
Chris
Technical director CKCCOMPUSCRIPT
Apple Computers, Intel, Roland audio, ATI, Microsoft, Sun Solaris, Cisco and
Silicone Graphics.
Wholesale distributor and specialist audio visual computers and servers
FREE SUPPORT @,
http://www.ckccomp.plus.com/site/page.HTM
(e-mail address removed)
 
Stylus said:
Hi peeps, [snip]

On the next cold boot the fans start but screen stays black. No BIOS
beeps, etc. On the next day the board boots again - maybe.

CMOS-clearing might (I'm not certain) helps that first boot, but is
useless afterwards. Swapping ram and VGA shows that the problem is in
the CPU or mobo. I'd guess 99% mobo, at this point. (Dead Athlons
don't power up once in a blue moon, do they?).

Is there anything I can check (capacitors etc) and try to fix before
trashing it for good? Damn, there's few things I hate more than those
voodoo 'on the brink of working but not there' situations ...
Click to expand...

What motherboard are we talking about here?

Replace the cmos battery with a new one, perform a bios reset - with ALL
power removed (unplug from the wall socket) from the pc, boot up and
enter the bios setup, load the optimised defaults, save and reboot,
enter the bios and setup anything else required.

Some nforce-2 motherboards are known to have initialisation problems
with a cmos battery that is only just beginning to fail. As the other
poster says it may be psu but it's unlikely, and there are other things
to try first that cost much less, in time and money.

If the battery change doesn't resolve the problem, try unplugging any
extra hard / optical drives fitted and trying to boot, this will reduce
the strain on the psu and if dodgy it may boot.

There are other things you can do, try the above first and post back the
results.


HTH
 
Hi peeps,

I replaced a faulty-ish N-Force 2 mobo + Athlon XP combo in a friend's
computer. Inspecting it there was some 'rust powder'-like stuff next
to the serial/parallel/USB block, over SMD resistors. Spraying it with
compressed air removed it completely, and nothing seems blown or
physically damaged.
Click to expand...

Try to determine what/where this 'rust powder' is coming
from... likely you already tried to but it would certainly
help to know what's going on there before trying anything
else.

Basically if the board stays unpowered for a day or so it boots fine -
the first time. Windows loads and works, etc. Subsequent warm boots
are fine too.
Click to expand...

You didn't even mention the board make/model/revision...
this can sometimes be pretty important. A link to a nice
big picture might help too if it shows where this 'rust'
was.
On the next cold boot the fans start but screen stays black. No BIOS
beeps, etc. On the next day the board boots again - maybe.
Click to expand...

Could be battery, power supply, or possibly bios settings.
Try clearing the CMOS and leaving it at defaults.

CMOS-clearing might (I'm not certain) helps that first boot, but is
useless afterwards. Swapping ram and VGA shows that the problem is in
the CPU or mobo. I'd guess 99% mobo, at this point. (Dead Athlons
don't power up once in a blue moon, do they?).
Click to expand...

If possible, try underclocking the FSB, disable AGP 8X in
bios. There might be other things more specific to the
particular board make/model.
Is there anything I can check (capacitors etc) and try to fix before
trashing it for good? Damn, there's few things I hate more than those
voodoo 'on the brink of working but not there' situations ...
Click to expand...

A bios update (or revert to older version, even backwards a
couple versions if it's currently running newest bios
version) could also be tried.
 
Try to determine what/where this 'rust powder' is coming
from... likely you already tried to but it would certainly
help to know what's going on there before trying anything
else.
Click to expand...

From what he told me, the only likely cause is 'watery' compressed air
(when you turn the can upside down). I got it after the fact.
You didn't even mention the board make/model/revision...
this can sometimes be pretty important. A link to a nice
big picture might help too if it shows where this 'rust'
was.
Click to expand...

Asus A7N8X. Watching the board from above the 'rust powder' area was
just below the parallel port, 2x2 cm wide.
Could be battery, power supply, or possibly bios settings.
Try clearing the CMOS and leaving it at defaults.
Click to expand...

Already done. Clear CMOS, enter BIOS, load setup defaults, save,
reboot.
If possible, try underclocking the FSB, disable AGP 8X in
bios. There might be other things more specific to the
particular board make/model.
Click to expand...

Hmm, I don't think it's gonna fix anything since the board worked fine
at those setting before. If it ever feels like booting again I'll give
a try.
A bios update (or revert to older version, even backwards a
couple versions if it's currently running newest bios
version) could also be tried.
Click to expand...

I might try a BIOS update, too, Thanks.
 
In cases like this I have found that 70% of the time it is the PSU not
delivering enough power on one of its lines, normally the 5v.
Chris
Click to expand...

It has the same behaviour with 3 different power supplies, including a
550 watt one. Everything but CPU, 1 stick of ram and VGA is already
disconnected.
 
What motherboard are we talking about here?
Click to expand...

Asus A7N8X
Replace the cmos battery with a new one, perform a bios reset - with ALL
power removed (unplug from the wall socket) from the pc, boot up and
enter the bios setup, load the optimised defaults, save and reboot,
enter the bios and setup anything else required.
Click to expand...

I'll try replacing the battery.
Some nforce-2 motherboards are known to have initialisation problems
with a cmos battery that is only just beginning to fail. As the other
poster says it may be psu but it's unlikely, and there are other things
to try first that cost much less, in time and money.
Click to expand...

Yep. It's no PSU problem.
There are other things you can do, try the above first and post back the
results.
Click to expand...

Thanks.
 
Stylus said:
Asus A7N8X
Click to expand...

That makes sense, I had two show the problem you describe (both
batteries measured 2.9v, new batteries - 3.2v)

It's so important to clear the cmos correctly too, you must have no
power connected to the pc at all.

{rant}
You know what - it really pisses me off that all these 'experts' jump up
and shout PSU at the first sign of hardware trouble, you'll find them
all over Usenet and it rarely is the psu.
{/rant}
 
I replaced a faulty-ish N-Force 2 mobo + Athlon XP combo in a friend's
<snip>

Just jumping in here, but... Are you sure that this "powder" stuff is dried
residue from failing capacitors?
 
Apollo said:
.... snip ...

{rant}
You know what - it really pisses me off that all these 'experts'
jump up and shout PSU at the first sign of hardware trouble,
you'll find them all over Usenet and it rarely is the psu.
Click to expand...

Actually, of things that can get quickly and painlessly fixed, the
PSU is one of the most likely components, and one of the cheapest
to replace. That makes those 'experts' experts more often than not
by claiming such, and perpetuates their place in the sun. Hey, it
works at times.
 
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