Can a faulty systemboard kill a psu?

[Ian R]

Hi

This might be one of those chicken/egg scenarios but thought I'd ask...

A friends PC wouldnt power up and the first thing I naturally suspected
would be the PSU.

I took out a fairly new 400w psu from a secondary system and took it over to
my friend.

Connected my PSU and it didnt bring his PC back to life. Oh well it was
worth a try.

Got home, put my PSU back into the tower it came from, switched on and my
goodness...

snap, crackle, pop, fizzle! Sparks literally flying out of the back of the
PSU.

I wonder if it could have been the faulty mobo in my friends system which
killed my PSU or just plain coincidence?

If theres a chance it was the mobo makes me wonder how we can test these
components without one killing the other?

Thanks for any info.

Ian

 

[Jan Alter]

Hi

This might be one of those chicken/egg scenarios but thought I'd ask...

A friends PC wouldnt power up and the first thing I naturally suspected
would be the PSU.

I took out a fairly new 400w psu from a secondary system and took it over
to my friend.

Connected my PSU and it didnt bring his PC back to life. Oh well it was
worth a try.

Got home, put my PSU back into the tower it came from, switched on and my
goodness...

snap, crackle, pop, fizzle! Sparks literally flying out of the back of the
PSU.

I wonder if it could have been the faulty mobo in my friends system which
killed my PSU or just plain coincidence?

If theres a chance it was the mobo makes me wonder how we can test these
components without one killing the other?

Thanks for any info.

Ian

Although I can't confirm your theory (suspecting it's certainly true) I once
had a questionable floppy drive in a system, whose PS had gone and I tried
the floppy in another system, hooking it up to the PS. Guess what? So it's
confirmed that single faulty components can short out others. I'm 99%
certain that that a faulty mb can also ruin a working PS, just as any other
faulty peripheral could.
There are clear ways to verify that a component is working without
having to do the switch test. One needs to have the knowledge to apply that
information and they are in business. An ohm meter is a good side kick

 

[John Doe]

Although I can't confirm your theory (suspecting it's certainly
true) I once had a questionable floppy drive in a system, whose PS
had gone and I tried the floppy in another system, hooking it up
to the PS. Guess what? So it's confirmed that single faulty
components can short out others. I'm 99% certain that that a
faulty mb can also ruin a working PS, just as any other faulty
peripheral could.

Right, but (for what it's worth) that might depend on how well the
power supply is made.

 

[Mike T.]

Hi

This might be one of those chicken/egg scenarios but thought I'd ask...

A friends PC wouldnt power up and the first thing I naturally suspected
would be the PSU.

I took out a fairly new 400w psu from a secondary system and took it over
to my friend.

Connected my PSU and it didnt bring his PC back to life. Oh well it was
worth a try.

Got home, put my PSU back into the tower it came from, switched on and my
goodness...

snap, crackle, pop, fizzle! Sparks literally flying out of the back of the
PSU.

I wonder if it could have been the faulty mobo in my friends system which
killed my PSU or just plain coincidence?

If theres a chance it was the mobo makes me wonder how we can test these
components without one killing the other?

Thanks for any info.

Ian

Anything's possible. The more likely scenario is that your 400w PSU was
just about dead and coincidentally died around the time it was re-installed.
If it really was the motherboard that killed the PSU, I'd suspect a short
between the motherboard and some other component. To test, I'd get a cheap
(really cheap, so if it does explode, who cares) PSU, and hook up that
motherboard, sitting outside of any PC case. -Dave

 

[Rod Speed]

Although I can't confirm your theory (suspecting it's certainly true)
I once had a questionable floppy drive in a system, whose PS had gone and I tried the floppy in
another system, hooking it up to the PS.
Guess what? So it's confirmed that single faulty components can short
out others. I'm 99% certain that that a faulty mb can also ruin a
working PS, just as any other faulty peripheral could.

A properly designed power supply should shut down when
anything overloads any of the rails. Thats part of the ATX spec.

Corse there are certainly badly designed power supplys that flout
the ATX spec and can kill stuff powered from them when they die.
That is also something that the ATX spec says that shouldnt be
allowed to happen by a separate shutdown mechanism.

There are clear ways to verify that a component is working without having to do the switch test.
One needs to have the knowledge to apply that information and they are in business. An ohm meter
is a good side kick

Thats not generally feasible with most motherboard faults.

The real way to test that situation is with a properly
designed power supply that will shut down properly
if the device thats powered by it has a fault.

 

[Rod Speed]

This might be one of those chicken/egg scenarios but thought I'd ask...

Tad radical.

A friends PC wouldnt power up and the first thing I naturally suspected would be the PSU.

I took out a fairly new 400w psu from a secondary system and took it over to my friend.

Connected my PSU and it didnt bring his PC back to life. Oh well it was worth a try.

Got home, put my PSU back into the tower it came from, switched on and my goodness...

snap, crackle, pop, fizzle! Sparks literally flying out of the back of the PSU.

I wonder if it could have been the faulty mobo in my friends system which killed my PSU or just
plain coincidence?

More likely to be a coincidence given that it
didnt happen with the system that wouldnt start.

If theres a chance it was the mobo makes me wonder how we can test these components without one
killing the other?

A properly designed power supply should shut down with
any motherboard fault. A badly designed power supply
can die if it trys to power a motherboard with a fault.