Question PSU whizzing while PC is off

[Angel Keidran]

My current PSU (Coolermaster MWE 750 80+ Gold modular) Is causing the PC to shutdown while gaming and is going to be replaced soon, but while i still can run the PC for normal usage i noted a thing: When the PC is fully shut down, a very annoying hissing/whizzing sound comes from the PSU itself, and since i can hear it while i'm in bed (kinda 1.50mt from the PC) is kinda loud...Is it normal? Could be dangerous for other hardware?

 

[Lutfij]

Not really, best tear down the system, breadboard and inspect each component to see if the noise is coming from the PSU or another part of the system. You should swap that PSU out ASAP, if the noise is indeed coming from the PSU while powered down but connected to the wall!

Also, why is the system still connected to the wall with the switch turned on? You should turn off the mains when the system isn't in use.

 

[Angel Keidran]

Not really, best tear down the system, breadboard and inspect each component to see if the noise is coming from the PSU or another part of the system. You should swap that PSU out ASAP, if the noise is indeed coming from the PSU while powered down but connected to the wall!

Also, why is the system still connected to the wall with the switch turned on? You should turn off the mains when the system isn't in use.

I don't have a main switch to where the PC is attached and i have stuff that needs to remain powered during the day...I tried to switch down the PSU, but the noise still comes out...I can unplug the PC when not in use, but keep doing do i was told it hurts teh PSU even more...Still this PSU will be switched in a month or so and i need it to work at least for normal usage...The only thing i have to be sure is that the PSU won't blow up in his last month of work...
EDIT: While powered, the PSU emits no noises apart for the fan and a veeeeeery soft buzzing sound (which i was told comes from some coil inside the PSU), but you must put your whole ear into the PSU to hear that...Don't know if means something or not, still when i power up the PC It goes up instantly and takes less than a minute to be ready to go...Only when gaming it shuts off or i get a green or grey screen, which i was told is caused by incorrect Voltage received by the GPU...