Death of my PC?

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I have a PC (over 5 years old) with MSI 6340 mobo and VIA KT133
chipset. Yesterday I was minding my own business happily using my PC
when I suddenly got the blue screen of death and the PC switched itself
off. I tried to reboot, but cannot even get as far as POST. The PSU
whirrs away as does the CPU fan. The green LED on the underside of my
HDD lights up, but otherwise activity is dead. On the front of the case
the LED lights for On state and amber for Standby/Sleep state are
simultaneously lit, when I power on. I can still power off by
depressing the ON button for a few seconds.

I'd like to think it was the PSU unit that was faulty, because that's a
cheap and easy replacement. But as powering on manages to energise both
fans and HDD LED, I have a horrible feeling that the CPU or mobo may
have blown. I can tell you that my CPU has never overheated nor have I
had any hardware problem in the past.I don't have a spare PSU to test
out. What does anyone think may be the likely cause. All suggestions
gratefully received.


Re: Death of my PC? wrote:

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Well, the first step is visual inspection. Ya gotta open it
up and look :-)

Do you have some thermal paste available ? You might need that,
so you can remove the heatsink and inspect the condition of
the processor. This web page gives an example of putting new
paste on the CPU. If there was a pad or phase change material
on the heatsink, I'd remove it and use some paste, as it may
be difficult to get good contact again when the heatsink
is reinstalled. And the heatsink can be rotated 180 degrees
by accident, so make sure the contact area on the bottom of
the heatsink, is centered over top of the CPU die, when you
put it back on.

This might not be exactly the right board, but it could be

At that vintage of board, the motherboard might not have
any protection against CPU overheat. If the heatsink/fan combo
were to fall off, because the clip broke, then the CPU might not
have any protection against overheat. Similarly, if the heatsink/fan
was clogged with dust, that might also have led to its demise.
Before disassembling anything, you can also take note of any
fans that have stopped spinning, like on your video card or

You would want to visually inspect the motherboard capacitors
(aluminum cylinders with a plastic sleeve on them, tops of
caps should be flat and should not bulge). Sometimes the tops
are OK, but when you look near the base, you see a brown stain
dried on the motherboard, and that is electrolyte that has
leaked and dried on. A failing cap will either cause the
quality of the Vcore voltage to the CPU to be degraded (leading
to the "high-low" alarm through the case speaker), or altogether
led to the destruction of the regulator circuit. In a case like that,
you may see a burnt MOSFET or the "donut with wire on it" could be
burnt as well.

The top of the cap has a cross or the letter K stamped in the
metal, and the purpose of the cutting of the metal, is to
form a pressure relief point, in case the cap wants to blow.
Capacitors can blow like a fire cracker, if they are stressed
the wrong way (and electrical engineering students like to
play that prank on one another, so everyone gets to see at
least one of them blow up).

If there is absolutely no visual evidence to go on (everything
is still in show room condition), you've pulled the heatsink/fan
and reapplied thermal paste (and the silicon die of the CPU is
not discolored), then the next step would be to try another
power supply. If you had a multimeter, you could try
testing the voltages as measured while the current power supply
is running. You can probe the top of the 20 pin connector and
compare the voltages seen, to an ATX power supply design spec.
(Pin side view of connector pinout is on page 29.)

If you don't own a multimeter, there is a danger you'd be
buying a power supply for nothing, and it could be that the
motherboard has failed in some invisible way.

It helps a lot, to have more than one computer, and be able
to borrow components from one, to test the other.

Another testing technique, is to remove components from the
motherboard, and use the beep error codes as an indicator of
health. To make the beep sound, the processor has to be
able to execute the BIOS. That means, if you just have a
motherboard, the processor with the heatsink/fan still installed
and working, and a power supply, that lot should be able to
beep the computer case speaker, and tell you there is no RAM
present. If that test fails, then at least you know it is
motherboard, CPU, or power supply, and you can then proceed
to disassemble the heatsink/fan for a look.

If you've never been inside a computer before, and you've lost
the manual, the very first thing you do, is make notes of
where all the wires go. On ribbon cable assemblies, there is
usually a red stripe on the pin 1 wire, and you also take note
of which way the red stripe goes.

Another rule for you, is to make sure power is removed from the
motherboard, before adding or removing components. The easiest
way to guarantee this, is to unplug the power supply, as there
is no mistaking the absence of power by following that rule.
Memory sticks can be damaged by adding or removing them when
the system still has power.


Re: Death of my PC?

"Paul" wrote:
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I wouldn't have the OP tinker with the CPU/HSF at all.  He/she stated that
the board has never overheated, and at this stage there is no expectation at
improving the dead board by chnging the TIM.


Re: Death of my PC?

Paul wrote:
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Thanks for your comprehensive response. However I can't get use beep
error codes as POST is never reached. I don't have a multimeter
otherwise I could have checked output voltages coming from PSU. I have
been inside a computer before, and am familiar with all the major
components although I have never mucked around with the CPU. I don't
have the knowledge to diagnose whether a component has failed, other
than to substitute similar components for the suspect one/s, and of
course I have no spare components, so I'm stymied there.

If I take the machine down to a shop to have the fault diagnosed, here
in the UK it would cost me far more than what the machine is worth, so
that looks out of the question. I can try a few simple things like
removing the CMOS battery for a few minutes and then replacing it. It's
even possible that the VGA card may be faulty, which is something you
did not mention. I will look for leaking electrolyte, but apart from a
little gathering dust, the inside appears pretty ok to me on first

As for the CPU I've never had an overheating problem, not even in the
recent past. I use Sandra to give  me a temp reading and the temp never
rises abobe 45 deg C, so i'm not convinced that I need to muck about
with CPU silver paste. The heatsink/fan combo has not fallen off.

Regrettably it looks like I'm going to need a new machine , unless my
few simple tests work a miracle. Isn't 5 1/4 years a bit soon for major
components to blow? My previous machine lasted over 10 years without a

Re: Death of my PC? wrote:

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OK, you can try this. Remove the RAM. Remove the video card.
Remove any PCI cards. Try just processor+heatsink/fan, the motherboard,
and the power supply. Can you get a beep code that way ? If it
doesn't beep, then one of the three items is defective. That
is as close as I can get, without having you use a multimeter
to check the voltages from the PSU.

In terms of probabilities, the power supply is the most likely
offender. At least with the cheap power supplies in circulation
these days.

There was a huge batch of bad capacitors, and maybe your motherboard
was before that batch was used. Millions of bad capacitors were
shipped, and many motherboards fell victim to premature capacitor
failure. If the motherboard was manufactured before or after that
incident, then the motherboard should be pretty reliable.

This guy makes a living replacing bad capacitors: /

There were even class action suits raised due to the bad caps: /

The power supply is the weakest link. Disk drives would probably
be next on my list, but your problem is not likely to be the
disk, because you'd still be able to get into the BIOS.
Processors also tend to be pretty reliable. So, if you do
your test with the motherboard, processor, power supply, and
there is no response, then the power supply would be
swapped first. If still no joy, I'd swap out the motherboard
second. Followed by replacing the processor third. Now,
when swapping the motherboard, you'd have an opportunity to
visually inspect the processor, and then you may find visible
signs of a processor problem.

As for design life, engineers can specify components for a
computer, where the intent is for the computer to last for
10 years. But for the most part, computers compete on price at
the low end of the market, so design life falls victim to
economics. The manufacturer only wishes to avoid excessive
warranty claims, so that is as long as the stuff has to last.

The internal computer case temperature plays a part in
determining the life of the components. At high temperatures,
for example, electrolytic capacitors have a life measured in
thousands of hours. At lower temperatures, they can last for
years. So if the objective is to have the stuff last
longer, then good cooling should help. A computer that is
"too quiet" ventilation-wise, may be heading for an early
grave (comparatively speaking). My personal wish, is that
all power supplies came with a knob that the user can adjust,
as I find the fans on my power supplies are too slow for
their own good.


Re: Death of my PC?

Can't be the disk drives because they only are read after the POST, and
I can't reach POST. I don't suspect my HDD for a moment. It's not the
capacitors. Had a look now and they are all fine, no leaks and nice
unblown flat tops. Don't think it's ram. I put a new module in January,
and never had any problem since. Reckon it's CPU or mobo at the moment
(or possibly PSU). I notice thee latter is makink a slight screeching
noise when powering up since the problem started.

Re: Death of my PC? wrote:
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When I had a similar problem earlier this year, it was recommended I
pull the power cord and remove the battery and leave it for some time.

After 20 minutes all was well.


Re: Death of my PC?> wrote:
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I had one of those boards that ended up dying due to bad capacitors on the
mainboard.  If you open up your case, look around the CPU for the green
cylinders; if they have bulging tops or are leaking, that would be a likely
culprit.  Sometimes I could coax it into working by flicking the switch on
the PSU instead of the front case switch, but eventually it died completely.

I ended up getting a new board and CPU from ebay, for fairly cheap that used
the same memory as a replacement, and that is what I am still using today.


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