Blown psu - a7v8x-x

[rikgale]

Hi
I have just blown up my spare computer. I was swaping the mobo over from an
Abit KR7A to an Asus A7V8X-X. Pluged everything and made sure all was good,
turned on the PSU at the wall for the 1st time, turned it on at the back (i
never got to actually turn the machine on). The little green light on the
mobo came on for about 2 secs, followed by a loud buzzing noise from the PSU
and a then after about 1 sec of the buzz, there was a loud bang. This fused
the house as well as totally buggering the PSU (assume that it is buggered
as there was lot of smoke coming from it.) Then the little green light went
out! I have to admit at this point I was not looking and the green light to
see if it went out before or after the bang, I was looking at the PSU in
horror at that point.
What I am curious to know is the likelyhood of having damaged the rest of
the computer i.e. the cpu (XP1800) and the RAM (2x256 PC2100) and the Gfx
card (ATI 9600)?
Any opinions/help will be most welcome
Rik

CPU - XP1800
RAM - 2 x256
Mobo - KR7A / A7V8X-X
PSU - Some 300Watt thing I got about 3 years ago (meridian tech. corps.)

 

[Fred Aspect]

Hi
I have just blown up my spare computer. I was swaping the mobo over from an
Abit KR7A to an Asus A7V8X-X. Pluged everything and made sure all was good,
turned on the PSU at the wall for the 1st time, turned it on at the back (i
never got to actually turn the machine on). The little green light on the
mobo came on for about 2 secs, followed by a loud buzzing noise from the PSU
and a then after about 1 sec of the buzz, there was a loud bang. This fused
the house as well as totally buggering the PSU (assume that it is buggered
as there was lot of smoke coming from it.) Then the little green light went
out! I have to admit at this point I was not looking and the green light to
see if it went out before or after the bang, I was looking at the PSU in
horror at that point.
What I am curious to know is the likelyhood of having damaged the rest of
the computer i.e. the cpu (XP1800) and the RAM (2x256 PC2100) and the Gfx
card (ATI 9600)?
Any opinions/help will be most welcome
Rik

CPU - XP1800
RAM - 2 x256
Mobo - KR7A / A7V8X-X
PSU - Some 300Watt thing I got about 3 years ago (meridian tech. corps.)

Rik,

I'm sorry to hear abt that. I can only say that I have blown a PSU in
the past (on an Asus P2B mobo), and I just simply needed to replace it.
No harm was done to the board or components.
I guess it all boils down to the reason why the PSU blew. Hopefully
others more knowledgable can shed some light on this, but I would
suspect that the components will be in the same condition as they were
before the PSU blew.

Fred.

 

[Paul]

Hi
I have just blown up my spare computer. I was swaping the mobo over from an
Abit KR7A to an Asus A7V8X-X. Pluged everything and made sure all was good,
turned on the PSU at the wall for the 1st time, turned it on at the back (i
never got to actually turn the machine on). The little green light on the
mobo came on for about 2 secs, followed by a loud buzzing noise from the PSU
and a then after about 1 sec of the buzz, there was a loud bang. This fused
the house as well as totally buggering the PSU (assume that it is buggered
as there was lot of smoke coming from it.) Then the little green light went
out! I have to admit at this point I was not looking and the green light to
see if it went out before or after the bang, I was looking at the PSU in
horror at that point.
What I am curious to know is the likelyhood of having damaged the rest of
the computer i.e. the cpu (XP1800) and the RAM (2x256 PC2100) and the Gfx
card (ATI 9600)?
Any opinions/help will be most welcome
Rik

CPU - XP1800
RAM - 2 x256
Mobo - KR7A / A7V8X-X
PSU - Some 300Watt thing I got about 3 years ago (meridian tech. corps.)

"This fused the house..." - I guess that means there was no fuse
protection inside the PSU.

In terms of damage potential, there are no guarantees as to how
much or little damage was done. If, for example, the failure had
been from 120V to the DC outputs (rather unlikely), then destruction
could be pretty complete. Back in the dawn of home computing, a
guy dropped 120V into the chassis of his computer, and blew the
tops off all the chips on the motherboard. I've had one accident
in the lab with an expensive piece of test gear, and it only
cost me two ICs - and that was with 120V to instrument ground
(I owe the repair guy a case of beer for that one - he fixed it
with one day turnaround).

For any subsystem where there is intervening power conversion,
you get some cushioning. The processor has the Vcore circuit.
The RAM has the Vdimm regulator. There is a good chance both
your processor and RAM are OK. The disk drives feed directly
from the PSU, so no cushion for them. The video card has its
regulation circuitry right on the video card (low voltage
regulators to run video RAM and GPU) - so while the GPU and
video RAM might be saved, the regulation circuitry itself
sees whatever the PSU has to throw at it. The video card may
also use 3.3V directly, which would be a direct exposure (if
the video card has VIVO for example, that might run off
3.3V.)

The loud bang from the PSU is likely the main 470 microfarad
cap(s) blowing. The sizzling could have been arc-over around
the caps, rectifier failure at switch-on, any number of
things - the PSU is toast, so dig a big hole in the back
yard for it. If you throw it in the garbage, cut the output
leads off it, so some genius doesn't try to "recycle" it.
Or write "kaboom" in marker pen on the casing

The big question is, how do you go about safely testing
the remaining pieces ? I don't have a good answer for
that, as whenever new parts meet old parts, there is
risk. A minimal check for each piece of gear, would be
to use an ohmmeter between each rail feeding a piece of
hardware. On a disk drive, you would "ohm" between +5 and +12,
+5 and GND, +12 and GND, in each case looking for a dead
short. This is just to avoid shorting out the new power
supply. There is still a risk that some I/O signals are
damaged, so no amount of testing will remove all the
risk.

If the new power supply you buy is fully featured with
protection mechanisms, you could always just connect the
whole computer to the new PSU and see what happens. I
don't think the damage could get much worse than it already
is, as long as the new power supply is fully protected (and
you are quick with the power switch, in the event that
something spectacular happens). If the whole computer will
not function, I would get a new motherboard, reuse processor
and RAM, experiment with the video card and monitor, change
video card if it won't drive out a signal, plug in the old
disk and CD and give them a try.

HTH,
Paul

 

[Zeneca]

Probably most of the componens will be unharmed.... but have a look on the
fixing of the mobo, to avoid any short circuit that could damage the PSU
again.

 

[rikgale]

"This fused the house..." - I guess that means there was no fuse
protection inside the PSU.

In terms of damage potential, there are no guarantees as to how
much or little damage was done. If, for example, the failure had
been from 120V to the DC outputs (rather unlikely), then destruction
could be pretty complete. Back in the dawn of home computing, a
guy dropped 120V into the chassis of his computer, and blew the
tops off all the chips on the motherboard. I've had one accident
in the lab with an expensive piece of test gear, and it only
cost me two ICs - and that was with 120V to instrument ground
(I owe the repair guy a case of beer for that one - he fixed it
with one day turnaround).

For any subsystem where there is intervening power conversion,
you get some cushioning. The processor has the Vcore circuit.
The RAM has the Vdimm regulator. There is a good chance both
your processor and RAM are OK. The disk drives feed directly
from the PSU, so no cushion for them. The video card has its
regulation circuitry right on the video card (low voltage
regulators to run video RAM and GPU) - so while the GPU and
video RAM might be saved, the regulation circuitry itself
sees whatever the PSU has to throw at it. The video card may
also use 3.3V directly, which would be a direct exposure (if
the video card has VIVO for example, that might run off
3.3V.)

The loud bang from the PSU is likely the main 470 microfarad
cap(s) blowing. The sizzling could have been arc-over around
the caps, rectifier failure at switch-on, any number of
things - the PSU is toast, so dig a big hole in the back
yard for it. If you throw it in the garbage, cut the output
leads off it, so some genius doesn't try to "recycle" it.
Or write "kaboom" in marker pen on the casing

The big question is, how do you go about safely testing
the remaining pieces ? I don't have a good answer for
that, as whenever new parts meet old parts, there is
risk. A minimal check for each piece of gear, would be
to use an ohmmeter between each rail feeding a piece of
hardware. On a disk drive, you would "ohm" between +5 and +12,
+5 and GND, +12 and GND, in each case looking for a dead
short. This is just to avoid shorting out the new power
supply. There is still a risk that some I/O signals are
damaged, so no amount of testing will remove all the
risk.

If the new power supply you buy is fully featured with
protection mechanisms, you could always just connect the
whole computer to the new PSU and see what happens. I
don't think the damage could get much worse than it already
is, as long as the new power supply is fully protected (and
you are quick with the power switch, in the event that
something spectacular happens). If the whole computer will
not function, I would get a new motherboard, reuse processor
and RAM, experiment with the video card and monitor, change
video card if it won't drive out a signal, plug in the old
disk and CD and give them a try.

HTH,
Paul

Many thanx, Paul, Zeneca and Fred

I'm going back to my parents place at the weekend as I know that there is a
spare PSU there. I also have my old mobo to test things out on as well.
I pretty much guessed that the PSU was toast from the moment it went bang.
As for the harddrive I am not too fussed as that was full of errors and on
its last legs anyways, which was why it was in my spare/test machine. I can
test the RAM, CPU and Gfx card in the older mobo, when I find somemore
thermal grease. What is going to annoy me is blowing up with DVD-Rom and
CDRW.

I'll try and remember to post back after the holiday weekend (UK) and let
you know how it goes

Thanx again

Rik