Maybe a little OT for uk.d-i-y, but my fellow regulars may have some ideas -
and I *am* trying to fix it myself!

Here's the problem . . .

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut down
before it's finished booting [2]

The symptoms are always the same. There's a crackle from the speakers, the
screens go blank, the power supply shuts down - but not completely. There is
a very quiet two-tone siren-type noise coming from somewhere in the region
of the motherboard. It has to be turned off at the mains before it shuts
down completely so that a re-start can be attempted.

In case it's relevant, I replaced the power supply a couple of months ago
because I was getting alarms saying that the 3.3v rail was running at 4
volts! [I wasn't sure whether that was really the case, or whether the
sensor was lying - but replaced the supply anyway, and that particular
problem went away]

Last night it had reached a state where it wouldn't complete the boot
process (symptoms as per [2]) - so I partially dismanted it, removed a
couple of bits I don't use these days (analog TV tuner and firewire board)
re-seated the memory boards, and blew all the dust off the motherboard.
After that, it ran quite well for a time - and worked all day today until
late afternoon, when it shut down again, and has gone back to failing before
it finishes booting. [I'm typing this on my laptop!]

Other than chucking it in a skip, has anyone got any ideas of the most
likely cause? I realise that it's a sort of "how long is a piece of string"
question, but someone just might have experienced the same symptoms, and
remember how they fixed it!


[1] Tower system - several years old - not state of the art - AMD 2600?
processor, 1GB of RAM, 120 GB HD, sound card, AGP graphics card driving 2
monitors - running Win XP Home SP2

[2] When this happens, it gets through the POST ok, puts up the Windows
screen with the scrolling horizontal dots, goes blank like it does just
before the cursor appears - but the cursor *doesn't* appear, it dies instead

TIA.
--
Cheers,
Roger
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Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Thu, 04 Feb 2010 20:06:05 +0000, Roger Mills wrote:

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut
down before it's finished booting [2]

The symptoms are always the same. There's a crackle from the speakers,
the screens go blank, the power supply shuts down - but not completely.
There is a very quiet two-tone siren-type noise coming from somewhere in
the region of the motherboard. It has to be turned off at the mains
before it shuts down completely so that a re-start can be attempted.

In case it's relevant, I replaced the power supply a couple of months
ago because I was getting alarms saying that the 3.3v rail was running
at 4 volts! [I wasn't sure whether that was really the case, or whether
the sensor was lying - but replaced the supply anyway, and that
particular problem went away]

TBH, it sounds as if the replacement PSU is failing. It's not entirely
clear if you had this problem BEFORE you replaced it, but I think that's
it.

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

"Roger Mills" wrote in message
...
Maybe a little OT for uk.d-i-y, but my fellow regulars may have some
ideas - and I *am* trying to fix it myself!

Here's the problem . . .

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut down
before it's finished booting [2]

The symptoms are always the same. There's a crackle from the speakers, the
screens go blank, the power supply shuts down - but not completely. There
is a very quiet two-tone siren-type noise coming from somewhere in the
region of the motherboard. It has to be turned off at the mains before it
shuts down completely so that a re-start can be attempted.

In case it's relevant, I replaced the power supply a couple of months ago
because I was getting alarms saying that the 3.3v rail was running at 4
volts! [I wasn't sure whether that was really the case, or whether the
sensor was lying - but replaced the supply anyway, and that particular
problem went away]

Last night it had reached a state where it wouldn't complete the boot
process (symptoms as per [2]) - so I partially dismanted it, removed a
couple of bits I don't use these days (analog TV tuner and firewire board)
re-seated the memory boards, and blew all the dust off the motherboard.
After that, it ran quite well for a time - and worked all day today until
late afternoon, when it shut down again, and has gone back to failing
before it finishes booting. [I'm typing this on my laptop!]

Other than chucking it in a skip, has anyone got any ideas of the most
likely cause? I realise that it's a sort of "how long is a piece of
string" question, but someone just might have experienced the same
symptoms, and remember how they fixed it!


[1] Tower system - several years old - not state of the art - AMD 2600?
processor, 1GB of RAM, 120 GB HD, sound card, AGP graphics card driving 2
monitors - running Win XP Home SP2

[2] When this happens, it gets through the POST ok, puts up the Windows
screen with the scrolling horizontal dots, goes blank like it does just
before the cursor appears - but the cursor *doesn't* appear, it dies
instead

TIA.
--
Cheers,
Roger

I would suspect power supply despite you having changed it. Possibly
previous problems have caused damage to the mobo.
You might try posting your original to uk.comp.homebuilt
There are some very knowledgeable and friendly folk there
Good luck,
Nick

On Thu, 04 Feb 2010 20:06:05 +0000, Roger Mills wrote:

Maybe a little OT for uk.d-i-y, but my fellow regulars may have some ideas -
and I *am* trying to fix it myself!

Here's the problem . . .

Check the system's motherboard for *obviously* duff capacitors (bulging
cans, split tops, leaks etc.) as in:

http://www.capacitorlab.com/visible-...tors-small.jpg

.... IME failures can really stress a PSU and dramatically shorten its
life; it might be that your motherboard's the problem and responsible for
taking out the original PSU and now the replacement.

Other possibilties:

Failed cooling fan
Dust build-up resulting in overheating
Conductive debris on the boards (or trapped underneath) resulting
in intermittent short
Bad solder joint or connector

The first three can be dealt with via a visual inspection; wiggling
everything inside the machin can sometimes help reproduce the fault if
it's the latter.

cheers

Jules

In an earlier contribution to this discussion, Owain
wrote:
On 4 Feb, 20:06, "Roger Mills" wrote:
The symptoms are always the same. There's a crackle from the
speakers, the screens go blank, the power supply shuts down - but
not completely. There is a very quiet two-tone siren-type noise
coming from somewhere in the region of the motherboard.

Motherboard model?

Owain


It's an MSI MS-6712 or somesuch (KT4V series)
--
Cheers,
Roger
_______
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checked.

Roger Mills wrote:
Maybe a little OT for uk.d-i-y, but my fellow regulars may have some ideas -
and I *am* trying to fix it myself!

Here's the problem . . .

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut down
before it's finished booting [2]

The symptoms are always the same. There's a crackle from the speakers, the
screens go blank, the power supply shuts down - but not completely. There is
a very quiet two-tone siren-type noise coming from somewhere in the region
of the motherboard. It has to be turned off at the mains before it shuts
down completely so that a re-start can be attempted.

In case it's relevant, I replaced the power supply a couple of months ago
because I was getting alarms saying that the 3.3v rail was running at 4
volts! [I wasn't sure whether that was really the case, or whether the
sensor was lying - but replaced the supply anyway, and that particular
problem went away]

Last night it had reached a state where it wouldn't complete the boot
process (symptoms as per [2]) - so I partially dismanted it, removed a
couple of bits I don't use these days (analog TV tuner and firewire board)
re-seated the memory boards, and blew all the dust off the motherboard.
After that, it ran quite well for a time - and worked all day today until
late afternoon, when it shut down again, and has gone back to failing before
it finishes booting. [I'm typing this on my laptop!]

Other than chucking it in a skip, has anyone got any ideas of the most
likely cause? I realise that it's a sort of "how long is a piece of string"
question, but someone just might have experienced the same symptoms, and
remember how they fixed it!


[1] Tower system - several years old - not state of the art - AMD 2600?
processor, 1GB of RAM, 120 GB HD, sound card, AGP graphics card driving 2
monitors - running Win XP Home SP2

[2] When this happens, it gets through the POST ok, puts up the Windows
screen with the scrolling horizontal dots, goes blank like it does just
before the cursor appears - but the cursor *doesn't* appear, it dies instead

TIA.
I'd put money on either a duff PSU or the CPU overheating. Check the
heatsink (and grease and fan). The grease can dry up.

On 4 Feb, 20:06, "Roger Mills" wrote:
Maybe a little OT for uk.d-i-y, but my fellow regulars may have some ideas -
and I *am* trying to fix it myself!

Here's the problem . . .

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut down
before it's finished booting [2]

The symptoms are always the same. There's a crackle from the speakers, the
screens go blank, the power supply shuts down - but not completely. There is
a very quiet two-tone siren-type noise coming from somewhere in the region
of the motherboard. It has to be turned off at the mains before it shuts
down completely so that a re-start can be attempted.

In case it's relevant, I replaced the power supply a couple of months ago
because I was getting alarms saying that the 3.3v rail was running at 4
volts! [I wasn't sure whether that was really the case, or whether the
sensor was lying - but replaced the supply anyway, and that particular
problem went away]

Last night it had reached a state where it wouldn't complete the boot
process (symptoms as per [2]) - so I partially dismanted it, removed a
couple of bits I don't use these days (analog TV tuner and firewire board)
re-seated the memory boards, and blew all the dust off the motherboard.
After that, it ran quite well for a time - and worked all day today until
late afternoon, when it shut down again, and has gone back to failing before
it finishes booting. [I'm typing this on my laptop!]

Other than chucking it in a skip, has anyone got any ideas of the most
likely cause? I realise that it's a sort of "how long is a piece of string"
question, but someone just might have experienced the same symptoms, and
remember how they fixed it!

[1] Tower system - several years old - not state of the art - AMD 2600?
processor, 1GB of RAM, 120 GB HD, sound card, AGP graphics card driving 2
monitors - running Win XP Home SP2

[2] When this happens, it gets through the POST ok, puts up the Windows
screen with the scrolling horizontal dots, goes blank like it does just
before the cursor appears - but the cursor *doesn't* appear, it dies instead

TIA.
--
Cheers,
Roger
_______
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Clear out all dust - especially from the CPU

Re-seat the ram and graphics card

I'm not so sure that this will be a PSU or total motherboard issue if
the machine runs for a while before shutting down. This is normally
heat related.

dg

On 4 Feb, 21:17, Chris Bartram wrote:
Roger Mills wrote:
Maybe a little OT for uk.d-i-y, but my fellow regulars may have some ideas -
and I *am* trying to fix it myself!

Here's the problem . . .

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut down
before it's finished booting [2]

The symptoms are always the same. There's a crackle from the speakers, the
screens go blank, the power supply shuts down - but not completely. There is
a very quiet two-tone siren-type noise coming from somewhere in the region
of the motherboard. It has to be turned off at the mains before it shuts
down completely so that a re-start can be attempted.

In case it's relevant, I replaced the power supply a couple of months ago
because I was getting alarms saying that the 3.3v rail was running at 4
volts! [I wasn't sure whether that was really the case, or whether the
sensor was lying - but replaced the supply anyway, and that particular
problem went away]

Last night it had reached a state where it wouldn't complete the boot
process (symptoms as per [2]) - so I partially dismanted it, removed a
couple of bits I don't use these days (analog TV tuner and firewire board)
re-seated the memory boards, and blew all the dust off the motherboard.
After that, it ran quite well for a time - and worked all day today until
late afternoon, when it shut down again, and has gone back to failing before
it finishes booting. [I'm typing this on my laptop!]

Other than chucking it in a skip, has anyone got any ideas of the most
likely cause? I realise that it's a sort of "how long is a piece of string"
question, but someone just might have experienced the same symptoms, and
remember how they fixed it!

[1] Tower system - several years old - not state of the art - AMD 2600?
processor, 1GB of RAM, 120 GB HD, sound card, AGP graphics card driving 2
monitors - running Win XP Home SP2

[2] When this happens, it gets through the POST ok, puts up the Windows
screen with the scrolling horizontal dots, goes blank like it does just
before the cursor appears - but the cursor *doesn't* appear, it dies instead

TIA.

I'd put money on either a duff PSU or the CPU overheating. Check the
heatsink (and grease and fan). The grease can dry up.

I can't know remember what the tone pattern was but I was getting a
shutdown situation which was due to a poor contact situation in one of
the RAM boards. Re-seating them both cured it.

Rob

In an earlier contribution to this discussion, Bob Eager
wrote:
On Thu, 04 Feb 2010 20:06:05 +0000, Roger Mills wrote:

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut
down before it's finished booting [2]


TBH, it sounds as if the replacement PSU is failing. It's not entirely
clear if you had this problem BEFORE you replaced it, but I think
that's it.

No, I didn't have *this* problem before replacing the power supply. The
problem I did have was that MSI's monitoring program - PC Alert 4 - detected
that the 3.3v supply was too high, and went into alarm - a very loud
two-tone siren noise - but didn't actually shut down. Mind you, *I* shut it
down pretty smartish when this happened. This hasn't happened with the new
supply - and PC Alert 4 has always shown sensible values for all the supply
voltages.

I accept that they *may* be related, but the new problem is different in
that is *does* shut down, with absolutely no warning. The siren noise which
occurs after shutdown is a very subdued version of the alarm I got when PC
Alert4 detected that the 3.3v supply was too high.
--
Cheers,
Roger
_______
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Roger Mills
wibbled on Thursday 04 February 2010 20:06

Maybe a little OT for uk.d-i-y, but my fellow regulars may have some ideas
- and I *am* trying to fix it myself!

Here's the problem . . .

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut down
before it's finished booting [2]

Stupid question: are the fans (in particular the CPU fan running (and stay
running) correctly? Symptoms like this *could* be the overheat protection
kicking in.

Next thing I'd try is boot it off a memtest86+ image[1] (floppy, CD, USB,
whatever works for you) and see how long it manages that - and revealingly,
if the memtest flags any errors before the PC dies.

When it dies, have a sniff and feel around (ooh err) and see if anything is
running excessivly hot - in particular, PSU, CPU, main chipsets.

Just some thoughts - these things are always a stab in the dark...

--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

"Jules" wrote in message
news
On Thu, 04 Feb 2010 20:06:05 +0000, Roger Mills wrote:

Maybe a little OT for uk.d-i-y, but my fellow regulars may have some
ideas -
and I *am* trying to fix it myself!

Here's the problem . . .

Check the system's motherboard for *obviously* duff capacitors (bulging
cans, split tops, leaks etc.) as in:

http://www.capacitorlab.com/visible-...tors-small.jpg

... IME failures can really stress a PSU and dramatically shorten its
life; it might be that your motherboard's the problem and responsible for
taking out the original PSU and now the replacement.

Other possibilties:

Failed cooling fan
Dust build-up resulting in overheating
Conductive debris on the boards (or trapped underneath) resulting
in intermittent short
Bad solder joint or connector

The first three can be dealt with via a visual inspection; wiggling
everything inside the machin can sometimes help reproduce the fault if
it's the latter.


Lots of good ideas in all the replies. I'd change the PSU as a matter of
course (they're cheap or you could get one from a scrap PC). Cleaning's
also an easy thing to do so do it. The only component failures which are
common are caps bursting or backup batteries corroding, caps you can see and
either remove or replace, batteries tend to leak crap all over the place and
trash the motherboard.

The other thing worth doing on an old system is checking for cracked solder
joints especially on the through-hole mini-fit junior power connectors (the
big white ones where the power goes into the motherboard), there can be a
fair stress on these and the industry went through a learning curve with
unleaded solder a little while back - re-flowing cracked joints on power
connectors is one of my favourite fixes as it gets you real super-hero
status. The symptoms are often as you describe, random shutdown without
warning. In your case you describe a partial shutdown as it sounds like at
least some of the rails are still up - that would fit with cracked joints
too. Don't bother looking in the first instance as you'll probably not see
a crack, just wiggle the connector and see if it fails, if it does you can
then either get the microscope out or just reach for the soldering iron.

In an earlier contribution to this discussion, Jules
wrote:

Check the system's motherboard for *obviously* duff capacitors
(bulging cans, split tops, leaks etc.) as in:

http://www.capacitorlab.com/visible-...tors-small.jpg


Thanks, I'll take it apart again, and have a closer look.

... IME failures can really stress a PSU and dramatically shorten its
life; it might be that your motherboard's the problem and responsible
for taking out the original PSU and now the replacement.

Other possibilties:

Failed cooling fan

No, PC Alert4 is reporting the CPU fan speed as just under 5000RPM, which is
normal

Dust build-up resulting in overheating

I've given everything a good blow out with an aerosol-based Air Duster

Conductive debris on the boards (or trapped underneath) resulting
in intermittent short

Nothing obvious, and it's had a good blow!

Bad solder joint or connector


Possibly - but it's worked for about 7 years!

The first three can be dealt with via a visual inspection; wiggling
everything inside the machin can sometimes help reproduce the fault if
it's the latter.


I'll have another go! Thanks for your comments.
--
Cheers,
Roger
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checked.

In an earlier contribution to this discussion, Cicero
wrote:

If the two-tone siren noise is regular it's remotely possible that
you're getting a heat related shutdown - just possible even during
booting. It's possible that the CPU heat sink and / or fan is clogged
or partly unseated.

On the few occasions that I've had such a heat related shutdown (set
in Bios) the speaker noise has been quite loud but it's still worth a
check on your CPU / fan / heatsink. It's just possible that the
internal speaker is also covered in sound-muffling detritus. Have a
look at the 'Mucky pictures thread in uk.comp.homebuilt for some idea
of what can happen.

I've given my system a good blow out with an air duster - so I don't think
there's any muffling left, or unscheduled insulation round the CPU and
heatsink.

I'm running a program called PC Alert4 - supplied by MSI with the
motherboard - which monitors things like supply voltages, CPU and system
temperatures, and CPU fan speed - and when the thing *does* work, these are
quite normal, with no hint of a problem. If PC Alert4 detects a problem, it
sounds the siren very loud - like it did when I had an over-voltage on the
3.3v rail, which caused me to change the power supply. So, if there *is* a
problem like that, it must be happening *very* suddenly - and shutting down
before PC Alert 4 detects it. With the current problem, the siren noise is
only audible *after* shutdown - and is then very feint - probably because
the power supply has more or less shut down, so there's not much urge
available to drive it.
--
Cheers,
Roger
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checked.

In an earlier contribution to this discussion, Chris Bartram
wrote:

I'd put money on either a duff PSU or the CPU overheating. Check the
heatsink (and grease and fan). The grease can dry up.

I will check that but - as reported in other posts - the monitoring program
(PC Alert4) is reporting quite normal CPU temperatures and fan speeds when
the thing *does* condescend to work.
--
Cheers,
Roger
_______
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checked.

In article , Bob Eager
scribeth thus
On Thu, 04 Feb 2010 20:06:05 +0000, Roger Mills wrote:

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut
down before it's finished booting [2]

The symptoms are always the same. There's a crackle from the speakers,
the screens go blank, the power supply shuts down - but not completely.
There is a very quiet two-tone siren-type noise coming from somewhere in
the region of the motherboard. It has to be turned off at the mains
before it shuts down completely so that a re-start can be attempted.

In case it's relevant, I replaced the power supply a couple of months
ago because I was getting alarms saying that the 3.3v rail was running
at 4 volts! [I wasn't sure whether that was really the case, or whether
the sensor was lying - but replaced the supply anyway, and that
particular problem went away]

TBH, it sounds as if the replacement PSU is failing. It's not entirely
clear if you had this problem BEFORE you replaced it, but I think that's
it.


Second that PSU's are about the number one PC problem area.

Check also that the processor is seated properly on the heatsink and
look for any bulging caps..
--
Tony Sayer

In message , Roger Mills
writes
In an earlier contribution to this discussion, Bob Eager
wrote:
On Thu, 04 Feb 2010 20:06:05 +0000, Roger Mills wrote:

Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut
down before it's finished booting [2]


TBH, it sounds as if the replacement PSU is failing. It's not entirely
clear if you had this problem BEFORE you replaced it, but I think
that's it.

No, I didn't have *this* problem before replacing the power supply. The
problem I did have was that MSI's monitoring program - PC Alert 4 - detected
that the 3.3v supply was too high, and went into alarm - a very loud
two-tone siren noise - but didn't actually shut down. Mind you, *I* shut it
down pretty smartish when this happened. This hasn't happened with the new
supply - and PC Alert 4 has always shown sensible values for all the supply
voltages.

I accept that they *may* be related, but the new problem is different in
that is *does* shut down, with absolutely no warning. The siren noise which
occurs after shutdown is a very subdued version of the alarm I got when PC
Alert4 detected that the 3.3v supply was too high.

What's a new PSU going to cost, £25?

Swap it out and try it


--
geoff

http://www.capacitorlab.com/visible-...tors-small.jpg
Thanks, I'll take it apart again, and have a closer look.

I'll second this as a strong possibility - also check out badcaps.net
for more pics.

Your machine sounds like it's acting like my previous machine did,
failing gradually and progressively more often over time - it turns
out I had a single slightly bulged capacitor, and you had to look
hard to notice it - the stamped "cross" on the top was just a tiny
bit more convex than the others...

It drove me mad for about 18 months trying to figure out what the
hell it might be - trying to exclude all possibility of it being a
software / bad RAM issue etc.

The mode of failure seems to vary from what you're seeing to just
refusing to switch on at all any more - which is what happened to
at least one of my colleagues with a machine of that vintage - a
quick glance confirmed my suspicion that it was capacitor failure.

In message , Roger Mills
writes
The symptoms are always the same. There's a crackle from the speakers, the
screens go blank, the power supply shuts down - but not completely. There is
a very quiet two-tone siren-type noise coming from somewhere in the region
of the motherboard.
The two tone siren usually indicates something (the CPU most likely) is
overheating.

As soon as it restarts can you access the BIOS and check the PC Health
status for the CPU temperatures etc?

Given the age of it, I'd suspect the CPU fan is clogged with dust and
likely the VRM capacitors on the motherboard are stuffed. Possibly the
new PSU is also failing and I'd check *all* the power connections to the
motherboard are properly fitted.

--
Clint Sharp

In article ,
Roger Mills wrote:
Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut
down before it's finished booting [2]

[snip]

You don't say what the motherboard is. I had just this with an Asus one.
Basically, it decided the main processor was getting too hot (it wasn't)
and shut things down. It had a prog supplied with the motherboard software
which showed the temperature of various things and fan speeds etc too. And
that told of the non existent overheating. I never found out how the
temperature was measured (a sensor in the chip or elsewhere?) but tried
cleaning and reseating the chip. Which appeared to work for a short time,
but back came the fault. Replaced the motherboard but kept the main
processor and memory and it's been fine ever since. Of course it could
also have been a software fault in the BIOS.

--
*When you've seen one shopping centre you've seen a mall*

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
scribeth thus
In article ,
Roger Mills wrote:
Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut
down before it's finished booting [2]

[snip]

You don't say what the motherboard is. I had just this with an Asus one.
Basically, it decided the main processor was getting too hot (it wasn't)
and shut things down. It had a prog supplied with the motherboard software
which showed the temperature of various things and fan speeds etc too. And
that told of the non existent overheating. I never found out how the
temperature was measured (a sensor in the chip or elsewhere?)

Its right underneath the chip usually, sort of springing up a little
bit on long "ish" leads...


but tried
cleaning and reseating the chip. Which appeared to work for a short time,
but back came the fault. Replaced the motherboard but kept the main
processor and memory and it's been fine ever since. Of course it could
also have been a software fault in the BIOS.

Course now you may have the change the whole lot depending on the mother
board requirements. We've got this problem in that you can't find IDE
drives with large capacities there're all SATA...
--
Tony Sayer

On 04/02/10 21:14, Roger Mills wrote:
In an earlier contribution to this discussion, Owain
wrote:
On 4 Feb, 20:06, "Roger Mills" wrote:
The symptoms are always the same. There's a crackle from the
speakers, the screens go blank, the power supply shuts down - but
not completely. There is a very quiet two-tone siren-type noise
coming from somewhere in the region of the motherboard.

Motherboard model?

Owain


It's an MSI MS-6712 or somesuch (KT4V series)

That looks to be about the right age to have capacitor rot. There was a
batch of duff capacitors at about that time. Look for bulging/leaking
capacitors, particularly near the processor socket.

Check the mobo manual, what does it say about the two-tone beeps?


--
Bernard Peek

"Roger Mills" wrote in message
...
In an earlier contribution to this discussion, Jules
wrote:

Bad solder joint or connector

Possibly - but it's worked for about 7 years!


Don't let that trick you, solder cracks are progressive. They're caused by
a combination of mechanical stress and thermal cycling (which is mechanical
stress as well I guess).

In article ,
tony sayer wrote:
I never found out how the
temperature was measured (a sensor in the chip or elsewhere?)

Its right underneath the chip usually, sort of springing up a little
bit on long "ish" leads...

Nothing like that on mine.

--
*I'm already visualizing the duct tape over your mouth

Dave Plowman London SW
To e-mail, change noise into sound.

In an earlier contribution to this discussion, John Rumm
wrote:
Roger Mills wrote:

It's an MSI MS-6712 or somesuch (KT4V series)

IME, random resets in recent years have most often been the result of
dodgy caps - often in the power conditioning parts of the motherboard.
These can also have knock on effects for the PSU creating mutually
induced problems.

I've had a close look at the caps, and can't *see* anything untoward - but
that doesn't necessarily mean they're ok.

(If you want a new motherboard to try, drop me a line - I have just
acquired a bunch of similar spec MSI boards after doing some upgrades
for clients - yours for the cost of postage).


That's a very generous offer - thanks! I'll give it some urgent thought -
but may opt for an upgrade anyway, since the whole thing's getting a bit
long in the tooth by computer standards.
--
Cheers,
Roger
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wrote:
Roger Mills wrote:

It's an MSI MS-6712 or somesuch (KT4V series)


Anyone know how to remove the heatsink from the processor? It's held on with
some sort of clip which fits in a deep groove across the middle - but I
can't work out how to undo it, and don't want to use too much brute force
and ignorance!
--
Cheers,
Roger
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On Fri, 5 Feb 2010 22:13:04 -0000, Roger Mills wrote:

Anyone know how to remove the heatsink from the processor? It's held on
with some sort of clip which fits in a deep groove across the middle -
but I can't work out how to undo it, and don't want to use too much
brute force and ignorance!

There will (should!) be a little handle/lever at one end of the clip,
ease that away from the heatsink and it should release tension in the
clip, which will then unhook at each end.

--
Cheers
Dave.

In article , Roger Mills
writes
wrote:
Roger Mills wrote:

It's an MSI MS-6712 or somesuch (KT4V series)


Anyone know how to remove the heatsink from the processor? It's held on with
some sort of clip which fits in a deep groove across the middle - but I
can't work out how to undo it, and don't want to use too much brute force
and ignorance!

Ignore the slot in the middle, that's just to pass the leaf spring part
of the clamp. The clip pulls down under the force of the leaf spring in
the middle with rectangular holes in the end pieces engaging on nipples
moulded into the processor socket. One end of the clip will be plain,
the other will have either a thumb tab to apply pressure to release the
clip or a small tab in which you insert a flat bladed screwdriver to do
same. Push down and move the tab to release it from the nipple on the
base.

Note the way the heatsink goes on for replacement.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

In article , Dave Plowman (News)
scribeth thus
In article ,
tony sayer wrote:
I never found out how the
temperature was measured (a sensor in the chip or elsewhere?)

Its right underneath the chip usually, sort of springing up a little
bit on long "ish" leads...

Nothing like that on mine.

Must be doing it another way or prolly don't actually do it. Three
boards here have got them..
--
Tony Sayer

In article ,
tony sayer wrote:
In article , Dave Plowman (News)
scribeth thus
In article ,
tony sayer wrote:
I never found out how the
temperature was measured (a sensor in the chip or elsewhere?)

Its right underneath the chip usually, sort of springing up a little
bit on long "ish" leads...

Nothing like that on mine.

Must be doing it another way or prolly don't actually do it. Three
boards here have got them..

I've got two desktops here - and of course had the original faulty
motherboard. All Asus with Athlon processors. None of them have any
obvious sensor under the processor or anywhere near it. All will read out
the various microprocessor temperatures and fan speeds etc in the BIOS or
by using PC Probe on the desktop. And the faulty board would sometimes
shut down just after startup before the processor had a chance to get even
remotely warm. With the BIOS showing it overheating. I assumed therefore
the sensor was in the processor. But the same processor in a new
motherboard has been fine. So I enquired no further. ;-)

--
*Why is the third hand on the watch called a second hand?

Dave Plowman London SW
To e-mail, change noise into sound.

On Feb 5, 10:20*am, tony sayer wrote:
In article , Dave Plowman (News)
scribeth thus

In article ,
* Roger Mills wrote:
Ever since last Friday evening, my main desktop computer[1] has been
shutting itself down without warning. This can happen after it's been
running for a few hours - often when left unattended - or it can shut
down before it's finished booting [2]

[snip]

You don't say what the motherboard is. I had just this with an Asus one.
Basically, it decided the main processor was getting too hot (it wasn't)
and shut things down. It had a prog supplied with the motherboard software
which showed the temperature of various things and fan speeds etc too. And
that told of the non existent overheating. I never found out how the
temperature was measured (a sensor in the chip or elsewhere?)

Its *right underneath the chip usually, sort of springing up a little
bit on long "ish" leads...

Chip temperature is determined by measuring the voltage across an on-
chip reference diode.

MBQ

In article
,
Man at B&Q wrote:
Its right underneath the chip usually, sort of springing up a little
bit on long "ish" leads...

Chip temperature is determined by measuring the voltage across an on-
chip reference diode.

Right - that makes sense. But didn't explain the fault on my motherboard
since the same chip is working fine on the new one. I did re-flow the
solder to the socket with no improvement. So it could have been perhaps a
software thingie - or broken track.

--
*Any connection between your reality and mine is purely coincidental

Dave Plowman London SW
To e-mail, change noise into sound.

In an earlier contribution to this discussion, John Rumm
wrote:
fred wrote:
In article , Roger Mills
writes
wrote:
Roger Mills wrote:

It's an MSI MS-6712 or somesuch (KT4V series)


Anyone know how to remove the heatsink from the processor? It's held
on with
some sort of clip which fits in a deep groove across the middle -
but I can't work out how to undo it, and don't want to use too much
brute force and ignorance!

Ignore the slot in the middle, that's just to pass the leaf spring
part of the clamp. The clip pulls down under the force of the leaf spring
in the middle with rectangular holes in the end pieces engaging on
nipples moulded into the processor socket. One end of the clip will
be plain, the other will have either a thumb tab to apply pressure to
release
the clip or a small tab in which you insert a flat bladed
screwdriver to do same. Push down and move the tab to release it
from the nipple on the base. Note the way the heatsink goes on for
replacement.

Some don't have a tab but just have a recess where the tip of a flat
bladed screwdriver can be inserted. You then use a bit of downward and
lateral pressure to pop the clip of the lugs on the side of the
socket.

Ah, that's the one - simple when you know how! Thanks.

Not sure it's done me much good though. I removed the heatsink,
re-distributed the conductive paste, replaced the heatsink and switched on.
[No monitor connected, so I can't see exactly what it's doing - but wanted
to see how long it would run for] After about 4 minutes - by which time it
would barely have finished loading all the start-up processes - it switched
itself off with the usual very quiet two-tone siren (which I've discoved is
a little speaker attached to the chassis connected by a thin wire to the
motherboard).

I felt all round the heatsink as soon as it happened, and it was very cool.
So if it *is* an over-temperature alarm of some sort, the sensor is pretty
certainly lying!
--
Cheers,
Roger
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checked.

In article ,
Roger Mills wrote:
Not sure it's done me much good though. I removed the heatsink,
re-distributed the conductive paste, replaced the heatsink and switched
on. [No monitor connected, so I can't see exactly what it's doing - but
wanted to see how long it would run for] After about 4 minutes - by
which time it would barely have finished loading all the start-up
processes - it switched itself off with the usual very quiet two-tone
siren (which I've discoved is a little speaker attached to the chassis
connected by a thin wire to the motherboard).

I felt all round the heatsink as soon as it happened, and it was very
cool. So if it *is* an over-temperature alarm of some sort, the sensor
is pretty certainly lying!

Does your machine give the temperatures etc in the BIOS setup pages? If so
go to these at startup - on mine you press 'delete' just after switch on
and see what it says. It will update the temp as it increases.
I also have PC Probe which does the same on the desktop. But that may be
an Asus specific prog. Although I'd expect other makers to have similar.

--
*Do infants enjoy infancy as much as adults enjoy adultery?

Dave Plowman London SW
To e-mail, change noise into sound.

In an earlier contribution to this discussion, Dave Plowman (News)
wrote:

Does your machine give the temperatures etc in the BIOS setup pages?
If so go to these at startup - on mine you press 'delete' just after
switch on and see what it says. It will update the temp as it
increases.

Yes, according the booklet which came with the motherboard, you can set a
critical CPU temperature, but I don't know whether it's enabled or not.
There's also a PC Health Check page which displays temperatures, voltages,
fan speeds, etc. The system is in bits at the moment, but I may put it back
together and have a look at that later - assuming it will run for long
enough to do so!

I also have PC Probe which does the same on the desktop. But that may
be an Asus specific prog. Although I'd expect other makers to have
similar.

There's a software program called PC Alert4 which does the same - and sounds
a loud alarm if any of the monitored parameters go outside their set limits.
I've had that on the screen all the time during the recent problems - and
it's not shown anything unusual, or produced any alarms - the PC just stops
dead with no warning! The CPU temperatures displayed are actually quite a
low lower than they used to be before I fitted a new CPU fan a year or so
ago - so it seems unlikely that the problems are due to having a lower
temperature set in the BIOS - because this would have caused problems before
the new fan was fitted.
--
Cheers,
Roger
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checked.

In article , Dave Plowman (News)
scribeth thus
In article ,
tony sayer wrote:
In article , Dave Plowman (News)
scribeth thus
In article ,
tony sayer wrote:
I never found out how the
temperature was measured (a sensor in the chip or elsewhere?)

Its right underneath the chip usually, sort of springing up a little
bit on long "ish" leads...

Nothing like that on mine.

Must be doing it another way or prolly don't actually do it. Three
boards here have got them..

I've got two desktops here - and of course had the original faulty
motherboard. All Asus with Athlon processors. None of them have any
obvious sensor under the processor or anywhere near it. All will read out
the various microprocessor temperatures and fan speeds etc in the BIOS or
by using PC Probe on the desktop. And the faulty board would sometimes
shut down just after startup before the processor had a chance to get even
remotely warm. With the BIOS showing it overheating. I assumed therefore
the sensor was in the processor. But the same processor in a new
motherboard has been fine. So I enquired no further. ;-)


The ones I looked at are indeed quite old, thats why there're doing not
a lot at the moment;!. The on chop diode sensor sounds a very good way
of doing that job...
--
Tony Sayer

In message
, Man
at B&Q writes
Chip temperature is determined by measuring the voltage across an on-
chip reference diode.
Not always.

MBQ



--
Clint Sharp

On Feb 7, 10:05*am, "Dave Plowman (News)"
wrote:
In article ,
* *Roger Mills wrote:

Not sure it's done me much good though. I removed the heatsink,
re-distributed the conductive paste, replaced the heatsink and switched
on. [No monitor connected, so I can't see exactly what it's doing - but
wanted to see how long it would run for] After about 4 minutes - by
which time it would barely have finished loading all the start-up
processes - it switched itself off with the usual very quiet two-tone
siren (which I've discoved is a little speaker attached to the chassis
connected by a thin wire to the motherboard).
I felt all round the heatsink as soon as it happened, and it was very
cool. So if it *is* an over-temperature alarm of some sort, the sensor
is pretty certainly lying!

Does your machine give the temperatures etc in the BIOS setup pages? If so
go to these at startup - on mine you press 'delete' just after switch on
and see what it says. It will update the temp as it increases.
*I also have PC Probe which does the same on the desktop. But that may be
an Asus specific prog. Although I'd expect other makers to have similar.


Download speedfan http://www.almico.com/speedfan.php It's worked on
all the machines I've tried it on.

MBQ

On Feb 7, 11:34*am, "Roger Mills" wrote:
In an earlier contribution to this discussion, Dave Plowman (News)

wrote:

Does your machine give the temperatures etc in the BIOS setup pages?
If so go to these at startup - on mine you press 'delete' just after
switch on and see what it says. It will update the temp as it
increases.

Yes, according the booklet which came with the motherboard, you can set a
critical CPU temperature, but I don't know whether it's enabled or not.

Are you sure the BIOS settings are not corrupted due to a flat
battery?

Have you tried resetting to defaults for the temp monitoring stuff?

MBQ

In article
,
Man at B&Q wrote:
On Feb 7, 11:34 am, "Roger Mills" wrote:
In an earlier contribution to this discussion, Dave Plowman (News)

wrote:

Does your machine give the temperatures etc in the BIOS setup pages?
If so go to these at startup - on mine you press 'delete' just after
switch on and see what it says. It will update the temp as it
increases.

Yes, according the booklet which came with the motherboard, you can
set a critical CPU temperature, but I don't know whether it's enabled
or not.

Are you sure the BIOS settings are not corrupted due to a flat
battery?

Have you tried resetting to defaults for the temp monitoring stuff?

Mine shows both the target and actual temp in the BIOS page. So presumably
the target would be wrong if the BIOS memory was suspect?

MBQ

--
*If you try to fail, and succeed, which have you done?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Clint Sharp wrote:
In message
, Man
at B&Q writes
Chip temperature is determined by measuring the voltage across an on-
chip reference diode.

Not always.

It does seem the logical way, given it's the temperature of the innards -
not the heatsink - that really matters.

--
*Succeed, in spite of management *

Dave Plowman London SW
To e-mail, change noise into sound.