PSU(or not?) problem!

[Minas]

Hello guys I am new to this forum,been watching for some time and I really admire your work!

 

Well,I know enough things about PC hardware and I have built up some systems myself but I am no expert.This time , I have come across a problem for the first time and I am really confused!

 

Ok so here it is,I have an old PC over here with a 300W PSU,problem is,PC starts fine but the PSU 5 seconds after boot starts to make a very strange noise,whining like its going to explode.At first I thought it was the PSU but no!I changed it with mine (corsair 430W) and this system forced my PSU to do the same sound also!

Now I am a little bit puzzled and I dont know what the problem is.

 

Any help guys?

 

Thanks in advance,

Minas.

[KenB]

Hi and welcome to ExTS

 

Are you sure that it is the PSU making the noise ?

Do you have case fans that could be the cause?

 

Suggest that you strip the motherboard of all cards and connections ( even the hard drive and DVD drive )

Leave only the 20(4) way power connection fitted.

 

Switch on.

 

Does the system still make the strange noises?

 

if not - add the RAM.

try again.

 

Add the other cards / connections one at a time - try switching on after each.

 

Make sure you leave the system long enough to be sure that the card / connection just added is not the cause.

[Minas]

Hey Ken thank you very much for your answer!I am sure that the noise is coming from the PSU.

Tried to only leave my motherboard plugged in with 20(4) power connector and still the same things happens.It also happens when I put another PSU.Problem must rely on the motherboard?

[KenB]

Problem must rely on the motherboard?

That would be my conclusion too - but never heard of this before ???

 

If you put the 430Watt back - is it still OK ?

[Minas]

Yes Ken 430Watt seems to work fine on my PC after that incident.I have never faced such a problem.

Might be a posssibility if some mobo cap is broken and asking for power so it makes the psu fan spin like crazy to give power or not?

 

Thanks for your help Ken.

[KenB]

It does sound as if something is trying to draw a lot of power - but I would have thought that a Corsair would have tripped out before getting over-loaded.

 

I can't see a blown capacitor drawing that much power ??????? Very odd.

Have you checked the capacitors for raised caps / discolouration / etc ?

[Plastic Nev]

Hi, can you be absolutely sure it is the PSU making the noise? High pitched whine noises can be very difficult to trace the cause, as above certain frequencies, our human direction senses get lost and can't sometimes pinpoint the exact location of the sound.

 

As an experiment, turn off the power to the monitor. Strangely enough, the monitors own inverter power system which generates the high voltage to make the backlight work, can give similar high pitched whines.

 

Nev.