Cold Boot issue

[KL]

Hi,

I am encountering a weird cold boot issue with my XP based system
recently (doesnt seem to appear with a warm boot) and hope someone here
could have an explanation.

Shortly after the system booted XP (even before the XP logo) the system
seems to crash and to reboot automatically. Upon the subsequent
(sometimes it needs a second one) XP start I get the typical error
message (safe mode, Last-Known-Good Configuration, ......).

Until yesterday a faulty RAM chip could have been the explanation but I
got a new one meanwhile. Also several disk checks didnt point to any bad
sectors.

Does anyone have an idea what else it could be respectively how I could
easily find the reason?

Thanks!

 

[KL]

Does it behave that way if you boot into Safe Mode originally? It might
be one of your drivers causing it to crash, Safe Mode is supposed to
load only the basic ones.

After it is booted, you might check the Event Viewer to see if anything
is showing up.

Clark

Thanks Clark, actually this might be a reason which I didnt think of
yet, also because the problem started rather suddenly without any
hardware modification or driver updates and appears right after the BIOS
passed to XP (where most drivers are probably not already really loaded).

Someone also pointed me to electrolytic capacitors on the mainboard
which might have bursted and I actually found some kind solid yellowish
mass on some of them (although I cant definitely say whether they are
bursted). Could this be an explanation as well?

Thanks again.

 

[Paul]

Thanks Clark, actually this might be a reason which I didnt think of
yet, also because the problem started rather suddenly without any
hardware modification or driver updates and appears right after the BIOS
passed to XP (where most drivers are probably not already really loaded).

Someone also pointed me to electrolytic capacitors on the mainboard
which might have bursted and I actually found some kind solid yellowish
mass on some of them (although I cant definitely say whether they are
bursted). Could this be an explanation as well?

Thanks again.

The capacitor should be a cylinder with a flat top. There is a seal
on the bottom of the capacitor, and it can push out if there is
internal gas pressure inside the cap. If the top bulges, there are
stress lines in the top of the cap, that are designed to open
if the pressure inside the capacitor becomes too high.

The electrolyte can leak out the bottom of the capacitor, if the
seal fails. Sometimes you'll see a brownish deposit under the
cap when this happens.

If the capacitors were part of the processor power conversion, then
their failure results in processor instability (crashing just
as desktop appears etc). They can be replaced, by someone skilled
with a soldering iron, and solder removal device (solder sucker).
Motherboards are easy to damage, as the PCB is not of the highest
quality. The copper foil delaminates pretty easily.

http://www.badcaps.net/images/caps/kt7/image004.png (bulging tops)
http://www.badcaps.net/images/caps/kt7/image005.png (seal popped on the bottom)

Paul

 

[KL]

The capacitor should be a cylinder with a flat top. There is a seal
on the bottom of the capacitor, and it can push out if there is
internal gas pressure inside the cap. If the top bulges, there are
stress lines in the top of the cap, that are designed to open
if the pressure inside the capacitor becomes too high.

The electrolyte can leak out the bottom of the capacitor, if the
seal fails. Sometimes you'll see a brownish deposit under the
cap when this happens.

If the capacitors were part of the processor power conversion, then
their failure results in processor instability (crashing just
as desktop appears etc). They can be replaced, by someone skilled
with a soldering iron, and solder removal device (solder sucker).
Motherboards are easy to damage, as the PCB is not of the highest
quality. The copper foil delaminates pretty easily.

http://www.badcaps.net/images/caps/kt7/image004.png (bulging tops)
http://www.badcaps.net/images/caps/kt7/image005.png (seal popped on
the bottom)

Paul

Thanks Paul. If there is an entire website dedicated to a hardware issue
it seems to be a rather serious one .

Some of the capacitors actually seem to be bulged at the top and had the
mentioned mass on them. As I am not really skilled in soldering I guess
it is time for a new mainboard.

Thanks again Paul, especially for the links.

 

[KL]

If you have decided to get a new motherboard anyway, then do some checks
first.

Thanks again for your helpful reply Clark, actually I already did most
of the checks you mentioned.

Meanwhile I purchased a new mainboard and am in the process of
installing it. I hope this will finally resolve this issue.

My only concern now is that capacitors of the power supply could also be
involved, hence I'd like to take a look at it too, but am a bit worried
about the remaining voltages and so maybe someone could state after
which time of being fully disconnected it should be safe to open it.

Try booting to a boot CD,since there may be a problem with your
hard drive.

The was one of my initial assumptions, but none of the checks I ran
pointed to a faulty hard drive.

Because you think you changed the memory, don't just assume it can't be
that. If you can remove part of it or change it around, you should try
that also. But memory problems should give you a beep code, or
motherboard lights or something.

Yes, I already checked for this too. I ran Memtest86+ (please dont
remind me how tedious it was to get a USB stick bootable on XP )
several times individually over the memory chips.

I am still leaning toward some bad device driver, or maybe a virus, or
even a loose cable. Since a warm boot works, the loose cable probably
isn't the cause, but you might check it anyway.

The reason why I almost ruled out the software possibility was not only
because it happened immediately after the XP booting (drivers and
especially viruses usually take place a bit later) but also because the
error remained even after several reinstalls.

I can't remember right
now what the difference as far as what is not loaded during a warm boot
as opposed to a cold boot.

From the operating system point of view there shouldnt be any difference.

I am assuming also that when you say cold boot, you just mean after a
complete shutdown, and immediate restart (at least 10 seconds, of
course). If you do have to leave it overnight before the problem
arises, the fact the hard drive also cools down might be a factor.

I actually tried both scenarios.

Thanks again Clark.

 

[KL]

Usually it's safe to open roughly 20-30 seconds later. Give
it a few minutes instead or to be extra cautious you could
wait a few hours but I have never found that necessary, out
of curiosity I check voltage on any I haven't waited long on
and never found dangerous voltage remaining.

Well, I waited for almost 20 hours . I opened it meanwhile and tried
to take as much care as possible. The power supply itself looked fine,
at least from looking at it.

However, technically speaking if you were to only take off
the screws and handle the outside of the casing, even with
it live (which I don't suggest doing, I'm just posing the
scenario for example) on a non-conductive surface you would
merely need to refrain from touching anything metal inside.

I was cautious because I am not really a hardware guy and missing
skills/knowledge/experience often scare people off .

Now that you've found the bad caps, there's not much point
in testing anything else until you have a known good
motherboard in for the testing. Instable motherboard can
lead one in all kinds of wrong directions.

Great News!

New motherboard and the problem still appears .

Well, I am slowly starting to get out of ideas as well as to suspect
either the power supply (even if it seems to look fine) or the video
card to cause it.

One thing to keep in mind is that if the system were
instable but not so much to crash, there is the potential
for data generated or transferred to have become corrupt. I
mean files written on the hard drive since the instability
began should be checked, and if the OS still isn't stable
(if reusing existing OS install instead of a clean
reinstall) then it should be installed again once the system
proves stable.

Yes, thats what I planned.


Thanks kony.

 

[KL]

Great News!

New motherboard and the problem still appears .

Well, I am slowly starting to get out of ideas as well as to suspect
either the power supply (even if it seems to look fine) or the video
card to cause it.

After switching to the internal video card, disconnecting all IDE drives
but the boot drive and using only the newest memory chip I begin to
believe it is actually the power supply.