help with fault diagnosis please

  • Thread starter Thread starter Dundonald
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Dundonald

Last night my computer just froze, dead, couldn't do anything. Under
a normal crash I'd either push the on off button at the front of the
case, or press the reset button, to let the computer boot up again.
Problem last night was this wouldn't work. The power light at the on
off switch at the front was still showing as on, the fans were still
turning. I was forced to switch off at the wall. Strange thing was
though, that after switching back on at the wall, the computer
returned to the previous state, as in, light on at the on off switch
at the front and the fans turning. So I switched off at the wall
again and left for a few hours, but again same problem after turning
on.

How can this happen?

I don't mind sorting this out myself if I know where to look. Could
it be that the CPU is crackered? HD? When I switch on at the wall I
don't hear the hard drive but this may be because the CPU isn't
churning. I guess I'm really wondering how to stop the computer
returning to an 'on' state so I can at least try to let everything try
to boot up again from scratch.

Any help really appreciated.

Thanks
 
Dundonald said:
Last night my computer just froze, dead, couldn't do anything. Under
a normal crash I'd either push the on off button at the front of the
case, or press the reset button, to let the computer boot up again.
Problem last night was this wouldn't work. The power light at the on
off switch at the front was still showing as on, the fans were still
turning. I was forced to switch off at the wall. Strange thing was
though, that after switching back on at the wall, the computer
returned to the previous state, as in, light on at the on off switch
at the front and the fans turning. So I switched off at the wall
again and left for a few hours, but again same problem after turning
on.

How can this happen?

I don't mind sorting this out myself if I know where to look. Could
it be that the CPU is crackered? HD? When I switch on at the wall I
don't hear the hard drive but this may be because the CPU isn't
churning. I guess I'm really wondering how to stop the computer
returning to an 'on' state so I can at least try to let everything try
to boot up again from scratch.

Any help really appreciated.

Thanks
Click to expand...

perhaps the front switch is stuck on.

power off, open case and unplug switch wires.

replace case and power up

what happens now.
 
perhaps the front switch is stuck on.

power off, open case and unplug switch wires.

replace case and power up

what happens now.
Click to expand...

Good suggestion, unfortunately still the same problem. I opened the
case, disconnected the small power cable at the motherboard from the
on / off button.

One thing I didn't mention, but I'm assuming people are aware, is that
the computer just isn't starting up at all (I'm accessing this group
using laptop). The monitor at the desktop isn't picking any signal
from the desktop because evidently it's not starting up even though
the power is always on.
 
Dundonald said:
Good suggestion, unfortunately still the same problem. I opened the
case, disconnected the small power cable at the motherboard from the
on / off button.

One thing I didn't mention, but I'm assuming people are aware, is that
the computer just isn't starting up at all (I'm accessing this group
using laptop). The monitor at the desktop isn't picking any signal
from the desktop because evidently it's not starting up even though
the power is always on.
Click to expand...

If it is a pre-built computer, please mention the brand and model number.

If you built the computer yourself, tell us the motherboard maker and
motherboard model number.

If I had to guess, your board has an 865, 875, or 848 chipset, and
your ICH5 or ICH5R Southbridge chip just burned up. The fault type is
called latchup, and can leave a burn mark on the top of the ICH5 chip.

When that has happened to some people, they were plugging in a USB device at
the time. At least one guy, has lost several motherboards to the same
fault type.

But without knowing the brand and model, it is pretty hard to blame it
on that. It could be lots of other things.

Processors don't generally drop dead on their own, at least not
without a bit of help (dodgy Vcore on motherboard etc).

Power supplies don't have a very good reputation for reliability, so
if you wanted to change a single component at random, the PSU would
be the one to switch out.

Paul
 
Last night my computer just froze, dead, couldn't do anything. Under
a normal crash I'd either push the on off button at the front of the
case, or press the reset button, to let the computer boot up again.
Problem last night was this wouldn't work. The power light at the on
off switch at the front was still showing as on, the fans were still
turning. I was forced to switch off at the wall. Strange thing was
though, that after switching back on at the wall, the computer
returned to the previous state, as in, light on at the on off switch
at the front and the fans turning. So I switched off at the wall
again and left for a few hours, but again same problem after turning
on.

How can this happen?

I don't mind sorting this out myself if I know where to look. Could
it be that the CPU is crackered? HD? When I switch on at the wall I
don't hear the hard drive but this may be because the CPU isn't
churning. I guess I'm really wondering how to stop the computer
returning to an 'on' state so I can at least try to let everything try
to boot up again from scratch.

Any help really appreciated.

Thanks
Click to expand...

So no way to get to BIOS? Tried a boot disk?
 
If it is a pre-built computer, please mention the brand and model number.

If you built the computer yourself, tell us the motherboard maker and
motherboard model number.

If I had to guess, your board has an 865, 875, or 848 chipset, and
your ICH5 or ICH5R Southbridge chip just burned up. The fault type is
called latchup, and can leave a burn mark on the top of the ICH5 chip.

When that has happened to some people, they were plugging in a USB device at
the time. At least one guy, has lost several motherboards to the same
fault type.

But without knowing the brand and model, it is pretty hard to blame it
on that. It could be lots of other things.

Processors don't generally drop dead on their own, at least not
without a bit of help (dodgy Vcore on motherboard etc).

Power supplies don't have a very good reputation for reliability, so
if you wanted to change a single component at random, the PSU would
be the one to switch out.

Paul
Click to expand...

I have a pre-built mesh computer with:

BIOS: American Megatrends AMI BIOS version 0908
Motherboard: ASUSTek Computer Inc. A8N-VM
CPU: AMD Athlon 64 3200 (2000 MHZ) Venice S939

Does this board tally up with your guess above? When the incident
happened I wasn't plugging anything in, I was playing a game, and it
just froze dead.
 
I have a pre-built mesh computer with:

BIOS: American Megatrends AMI BIOS version 0908
Motherboard: ASUSTek Computer Inc. A8N-VM
CPU: AMD Athlon 64 3200 (2000 MHZ) Venice S939
Click to expand...

What PSU make/model/ratings?


Does this board tally up with your guess above? When the incident
happened I wasn't plugging anything in, I was playing a game, and it
just froze dead.
Click to expand...


Having to unplug the PSU from AC power shows it had shut
itself off either from it's own failure or a failure of
connected components. What remains is to determine which is
the cause. Is anything under warranty still? If not you
might pull the PSU and leaving unplugged for awhile, open
and inspect it (failed capacitors being most likely).

A basic inspection of all system internals is also prudent,
especially capacitors on the motherboard and video card, and
checking that all cards are fully inserted into their
respective slots including memory, video, etc. Also check
whether the video card fan spins freely or if it might've
seized and allowed video card to overheat.

Since you are a gamer/were-gaming it seems a bit more likely
(than otherwise) the stress on the video card could have
damaged it (if there were some problem with it already), you
might pull the video card and see how the system reacts,
substituting some other video card if possible... even an
ancient PCI video card would suffice but ultimately the
safest course is to not try to power the system with this
PSU yet until you know if it's operating properly including
inspection and taking voltage readings with a multimeter.
 
Dundonald said:
Last night my computer just froze, dead, couldn't do anything. Under
a normal crash I'd either push the on off button at the front of the
case, or press the reset button, to let the computer boot up again.
Problem last night was this wouldn't work. The power light at the on
off switch at the front was still showing as on, the fans were still
turning. I was forced to switch off at the wall. Strange thing was
though, that after switching back on at the wall, the computer
returned to the previous state, as in, light on at the on off switch
at the front and the fans turning. So I switched off at the wall
again and left for a few hours, but again same problem after turning
on.

How can this happen?

I don't mind sorting this out myself if I know where to look. Could
it be that the CPU is crackered? HD? When I switch on at the wall I
don't hear the hard drive but this may be because the CPU isn't
churning. I guess I'm really wondering how to stop the computer
returning to an 'on' state so I can at least try to let everything try
to boot up again from scratch.

Any help really appreciated.

Thanks
Click to expand...


Hardware failure of some type

Open the machine up and check all connections...

unplug and replug devices and cables etc.

also pull out the power supply and shake it and smell it.

if you hear a rattle or is it smells burned then it;s probably bad

(try a different power supply if you are not sure)


after that remove non essential H/W etc
 
What PSU make/model/ratings?


Having to unplug the PSU from AC power shows it had shut
itself off either from it's own failure or a failure of
connected components. What remains is to determine which is
the cause. Is anything under warranty still? If not you
might pull the PSU and leaving unplugged for awhile, open
and inspect it (failed capacitors being most likely).

A basic inspection of all system internals is also prudent,
especially capacitors on the motherboard and video card, and
checking that all cards are fully inserted into their
respective slots including memory, video, etc. Also check
whether the video card fan spins freely or if it might've
seized and allowed video card to overheat.

Since you are a gamer/were-gaming
Click to expand...

I'd say "were gaming" is more appropriate, I'm not a gamer by any
means, that was the first time I'd played any type of game on the PC
for about 12 months.
 
Somewhere on the interweb "kony" typed:
What PSU make/model/ratings?





Having to unplug the PSU from AC power shows it had shut
itself off either from it's own failure or a failure of
connected components. What remains is to determine which is
the cause. Is anything under warranty still? If not you
might pull the PSU and leaving unplugged for awhile, open
and inspect it (failed capacitors being most likely).

A basic inspection of all system internals is also prudent,
especially capacitors on the motherboard and video card, and
checking that all cards are fully inserted into their
respective slots including memory, video, etc. Also check
whether the video card fan spins freely or if it might've
seized and allowed video card to overheat.

Since you are a gamer/were-gaming it seems a bit more likely
(than otherwise) the stress on the video card could have
damaged it (if there were some problem with it already), you
might pull the video card and see how the system reacts,
substituting some other video card if possible... even an
ancient PCI video card would suffice
Click to expand...

No need to substitute, the mobo has integrated graphics, pulling the video
card should let it boot up using on-board. Of course, if he's using on-board
(GeForce 6150) then he can't "pull the graphics card". It's a reasonable
mobo, my money's on PSU or serious dust buildup/fan/CPU failure.
 
Somewhere on the interweb "davy" typed:
First thing to do is to disconnect all USB devices, because any faulty
USB devices will affect boot up.

The first goal is to get bios POST... Power On Self test 'known as
bios boot', this you will get and be able to get into bios screen if
so wished with just the CPU, RAM and Graphic card only... the rest
inc. the hard drive can be unhooked.

The hard drive does not come into play until after the bios boot up,
it then gives a bleep saying all is ok handing the control over to
the CPU, only now does the hard drive come into play.

If you are not getting the bios to 'boot' nothing else will happen...
so we are looking at a duff bios battery, faulty power supply, faulty
video card, faulty mobo usually due to bad caps.... or the CPU itself,
this is the very last option to consider after all other options have
been exhausted, as damage can easily be done as it's not a matter of
removing it and refitting.

As a guess I would say either the bios battery
Click to expand...

??????

I have seen a lot of mobos with flat BIOS batteries before and they *never*
behave as this machine is. They always boot into BIOS and say something like
"New CPU fitted" or "CMOS not loaded" or they boot into the OS but show a
date years ago and look for drivers for anything that was previously
disabled in BIOS.
 
First thing to do is to disconnect all USB devices, because any faulty
USB devices will affect boot up

The first goal is to get bios POST... Power On Self test 'known as bios
boot', this you will get and be able to get into bios screen if so
wished with just the CPU, RAM and Graphic card only... the rest inc. the
hard drive can be unhooked.

The hard drive does not come into play until after the bios boot up, it
then gives a bleep saying all is ok handing the control over to the CPU,
only now does the hard drive come into play.

If you are not getting the bios to 'boot' nothing else will happen...
so we are looking at a duff bios battery, faulty power supply, faulty
video card, faulty mobo usually due to bad caps.... or the CPU itself,
this is the very last option to consider after all other options have
been exhausted, as damage can easily be done as it's not a matter of
removing it and refitting.

As I guess I would say either the bios battery or the power supply, any
of the above are worthy of trying by substitution, sometimes removing
and refitting the video card works strange wonders.

Davy
Click to expand...

Thanks Davy I will try a few tests in the order that you suggest, and
report back.
 
Thanks Davy I will try a few tests in the order that you suggest, and
report back.
Click to expand...


Dead battery won't shut the machine off like it did.
Hard drive isn't a factor either, just unplug it for now.

Odds are the PSU is dying and the system should not be
operated until you can independantly test the PSU - because
with it not putting out stable power, your parts are getting
who-knows-what quality of power.
 
Somewhere on the interweb "kony" typed:








No need to substitute, the mobo has integrated graphics, pulling the video
card should let it boot up using on-board. Of course, if he's using on-board
(GeForce 6150) then he can't "pull the graphics card". It's a reasonable
mobo, my money's on PSU or serious dust buildup/fan/CPU failure.
Click to expand...

Hi Shaun, thanks for your post. I pulled out the graphics card and I
have plugged the monitor in to the on board video. Still same
problem, as in, the power is automatically on when switched on at the
mains or at the back of the PSU. So I guess that rules out graphics
card. I checked graphic card fan and it rotates fine, as do all other
fans in the desktop. So out of interest when you say PSU, I'm trying
to understand what might cause the power to always be on. Is it that
the PSU is ignoring the toggle on / off switch ? On a previous test I
unhooked the toggle on /off switch cable at the motherboard. Is it a
common problem that PSU's fail on 'modern' machines? My last computer
before it was replaced last year by this desktop was 8 years old and
didn't have a problem with PSU.

About dust build - I did notice a bit of dust inside the desktop, on
the fans particularly, so I gave most things a quick clean. I'm
interested where else might cause problems with dust.

I took the heat sinc off the CPU to check for any obvious heat damage
and it looks OK.


 
First of all thanks for your post here's a response to your suggested
tests.
First thing to do is to disconnect all USB devices, because any faulty
USB devices will affect boot up
Done.

The first goal is to get bios POST... Power On Self test 'known as bios
boot', this you will get and be able to get into bios screen if so
wished with just the CPU, RAM and Graphic card only... the rest inc. the
hard drive can be unhooked.
Done.

The hard drive does not come into play until after the bios boot up, it
then gives a bleep saying all is ok handing the control over to the CPU,
only now does the hard drive come into play.
Click to expand...
If you are not getting the bios to 'boot' nothing else will happen...
so we are looking at a duff bios battery, faulty power supply, faulty
video card, faulty mobo usually due to bad caps.... or the CPU itself,
this is the very last option to consider after all other options have
been exhausted, as damage can easily be done as it's not a matter of
removing it and refitting.
Click to expand...

I unhooked graphic card, plugging monitor in to onboard video and had
same problem. (I didn't unhook the HD but that doesn't spin anyway so
it's not getting as far as HD). I have 2 x 512mb ram so I also took
one out at a time to test each one. I checked CPU by taking off the
heat sinc and found no obvious signs of damange. All fans seem to be
rotating OK. All these tests and still same problem. BIOS doesn't
come up, and no signal to the monitor. And as soon as I switch power
on to the PC it's as if the power is immediately on, as in, I don't
need to push the toggle on/off button at the front to start.

So is the onus on fault PSU? Suggest buying a replacement PSU and
testing again?
 
Somewhere on the interweb "Dundonald" typed:
Hi Shaun, thanks for your post. I pulled out the graphics card and I
have plugged the monitor in to the on board video. Still same
problem, as in, the power is automatically on when switched on at the
mains or at the back of the PSU. So I guess that rules out graphics
card. I checked graphic card fan and it rotates fine, as do all other
fans in the desktop. So out of interest when you say PSU, I'm trying
to understand what might cause the power to always be on. Is it that
the PSU is ignoring the toggle on / off switch ? On a previous test I
unhooked the toggle on /off switch cable at the motherboard. Is it a
common problem that PSU's fail on 'modern' machines? My last computer
before it was replaced last year by this desktop was 8 years old and
didn't have a problem with PSU.
Click to expand...

Ahh, the old days! An 8 year old computer probably sucked less than a
quarter of the power that this one does, the PSU was never stressed.

One other thing I suggest that you try; Disconnect the reset switch from the
mobo. It's flukey I know but sometimes they stick in the closed position....
About dust build - I did notice a bit of dust inside the desktop, on
the fans particularly, so I gave most things a quick clean. I'm
interested where else might cause problems with dust.
Click to expand...

Usually in/around the RAM and the power MOSFETs. It gets pushed in and
around that area by the CPU fan. Doesn't hurt, if you can afford it, to
spray the whole mobo with CO cleaner and let it run off and evaporate.
Concentrate on any areas where there are ICs with small pins/legs that are
dust-clogged too. Do that with the RAM and cards removed and spray into the
slots too. It's "fixed" machines for me before.
I took the heat sinc off the CPU to check for any obvious heat damage
and it looks OK.
Click to expand...

Cool. <g>

Good luck,
 
Somewhere on the interweb "Dundonald" typed:





Ahh, the old days! An 8 year old computer probably sucked less than a
quarter of the power that this one does, the PSU was never stressed.
Click to expand...

Good point.
One other thing I suggest that you try; Disconnect the reset switch from the
mobo. It's flukey I know but sometimes they stick in the closed position....
Click to expand...

Aye as a previous test I unhooked the cables at the motherboard and
last night I also took the front facia off of the case and toggled the
switch manually. Still the same problem :(
Usually in/around the RAM and the power MOSFETs. It gets pushed in and
around that area by the CPU fan. Doesn't hurt, if you can afford it, to
spray the whole mobo with CO cleaner and let it run off and evaporate.
Concentrate on any areas where there are ICs with small pins/legs that are
dust-clogged too. Do that with the RAM and cards removed and spray into the
slots too. It's "fixed" machines for me before.


Cool. <g>

Good luck,
Click to expand...

ta. I'm going to try out a new PSU tonight I think, see if that fixes
the problem.
 
Somewhere on the interweb "davy" typed:








??????

I have seen a lot of mobos with flat BIOS batteries before and they *never*
behave as this machine is. They always boot into BIOS and say something like
"New CPU fitted" or "CMOS not loaded" or they boot into the OS but show a
date years ago and look for drivers for anything that was previously
disabled in BIOS.
Click to expand...

OK Update everyone.

I finally got a bit of time to get out and buy a PSU. So I installed
the PSU and this sorted the problem with the unit not switching on /
off properly i.e. when I switch off at the back of the PSU or unplug
the mains then switch on at mains or back on at the back of the PSU
the computer is no longer immediately on, I have to push the power
on / off switch to switch it one, which is good.

HOWEVER - after pressing the switch and turning power on, the same
problem as before, as in no BIOS boot. SO I unplugged everything from
the motherboard bar the main power cable and the fan cables. The
monitor keyboard and mouse cables were connected at the back. So no
CD drive, no floppy, no HD, no nothing connected to motherboard. I
Switch on, and still, same problem. So, what is the problem:

1. flat battery on the motherboard?
2. motherboard dead?
3. CPU dead?

There are no visible signs of failure on the motherboard or on the CPU
if I take off the heat sinc and fan.

So what can I do next? Any ideas please ...
 
OK Update everyone.

I finally got a bit of time to get out and buy a PSU. So I installed
the PSU and this sorted the problem with the unit not switching on /
off properly i.e. when I switch off at the back of the PSU or unplug
the mains then switch on at mains or back on at the back of the PSU
the computer is no longer immediately on, I have to push the power
on / off switch to switch it one, which is good.

HOWEVER - after pressing the switch and turning power on, the same
problem as before, as in no BIOS boot. SO I unplugged everything from
the motherboard bar the main power cable and the fan cables. The
monitor keyboard and mouse cables were connected at the back. So no
CD drive, no floppy, no HD, no nothing connected to motherboard.
Click to expand...


.... but you still have the processor, heatsink/fan, 1 memory
module, and the video card, right? I mean try using the
integrated video, and try putting the one memory module in
different slots though actually you could probabl be lazy at
first and just leave all memory in at this point, later
removing all but one... but essentially if the PSU failed it
might have damaged something else so ultimately all parts
are suspect since the replacement PSU hasn't resolved the
problem - though it does seem like the prior PSU wasn't
working properly. I still suspect the video card some since
the problem happened when beginning to game.

I
Switch on, and still, same problem. So, what is the problem:

1. flat battery on the motherboard?
2. motherboard dead?
3. CPU dead?

There are no visible signs of failure on the motherboard or on the CPU
if I take off the heat sinc and fan.

So what can I do next? Any ideas please ...
Click to expand...

Is the new PSU a known quality unit capable of enough power
for your combination of parts?

Try clearing CMOS with AC power disconnected. I mean doing
it again even if you had already, and do this after having
removed the video card.
 
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