PSU making small buzzing

[Dalli]

Hi, as the title says my coolermaster mwe 550w 80+ bronze does make a veeeery low buzzing (?) sound when the pc is off, but I have to be really close to it and no surrounding noise.

Is this a commun psu thing or it happens sometimes and its ok or something is not right or I am in a grave danger (hope not  ).

Looking for you answers thanks in advance.

[Guest]

Normal.

 

[Praesi]

12 minutes ago, jonnyGURU said:

Normal.

 

Its normal the PSU makes noise when the PC is off? 

Not in my World.

[Guest]

13 minutes ago, Praesi said:

Its normal the PSU makes noise when the PC is off? 

Not in my World.

In your world are you unplugging the PC after you turn it off?  Are you using an old school AT power supply or do you flip the switch on the back of your PSU off after you shut down the PC?

 

An ATX PC that is "off" is still on.  It's plugged in and getting power, the +5VSB is live, which means the USB ports and RAM are still receiving power.  Therefore, the PSU must maintain the bus power.

 

 

[Mark Kaine]

20 minutes ago, Praesi said:

Its normal the PSU makes noise when the PC is off? 

Not in my World.

yep.......  what the heck is up with some PSUs someone else said they would smell like burned plastic and that would be fine!

 

 

that said maybe it's nothing to worry about I think @jonnyGURU knows a thing or two about PSUs...

Does it stop after a while though because that seems seriously weird.

 

ps: I have a PS3 that does the same, could that be also PSU? I always thought it's a condensator going bad..  

[Praesi]

1 minute ago, jonnyGURU said:

In your world are you unplugging the PC after you turn it off?  Are you using an old school AT power supply or do you flip the switch on the back of your PSU off after you shut down the PC?

 

An ATX PC that is "off" is still on.  It's plugged in and getting power, the +5VSB is live, which means the USB ports and RAM are still receiving power.  Therefore, the PSU must maintain the bus power.

 

 

None of my PSU´s as long i remember made any kind of noise when i turned the PC off.

Not the Gaming PC´s, not the Workstations. So if this is "normal", its actual new to me.

[Mark Kaine]

3 minutes ago, jonnyGURU said:

In your world are you unplugging the PC after you turn it off?  Are you using an old school AT power supply or do you flip the switch on the back of your PSU off after you shut down the PC?

 

An ATX PC that is "off" is still on.  It's plugged in and getting power, the +5VSB is live, which means the USB ports and RAM are still receiving power.  Therefore, the PSU must maintain the bus power.

 

 

ah! no my USB is off when I turn the PC off, seriously just a slight buzzing would annoy me so much lol... (it's a bios settings to power the USBs apparently which I learned recently)

[quan289]

33 minutes ago, Praesi said:

None of my PSU´s as long i remember made any kind of noise when i turned the PC off.

Not the Gaming PC´s, not the Workstations. So if this is "normal", its actual new to me.

Since the +5VSB rail is live when the PC is off, electricity is still passing through the windings in the PSU like the PFC coil and the 5VSB transformer. When electricity passes through them, it will vibrate - sometimes at an audible frequency which can come and go depending on the load; e.g. in this case, having multiples of USB devices plugged in. One unit can be very loud and can be heard 5 feet away, where another unit of the same model can be heard only if you press your ears against the PSU with minimal background noise (like the OP). And of course, you may not hear anything at all because it out of the frequency range that humans can hear.

[Guest]

1 hour ago, Mark Kaine said:

ah! no my USB is off when I turn the PC off, seriously just a slight buzzing would annoy me so much lol... (it's a bios settings to power the USBs apparently which I learned recently)

Right.. but you can't shut off +5VSB to your RAM.

 

[Dalli]

I mean if jonnyGURU himself said its normal then it is !

5 hours ago, Mark Kaine said:

ah! no my USB is off when I turn the PC off, seriously just a slight buzzing would annoy me so much lol... (it's a bios settings to power the USBs apparently which I learned recently)

yeah I have disabled powering my USBs from the bios (but they are still plugged-in idk if that matters) besides as jonny said it should be the RAM.

thanks again.