[SOLVED] New PSU making slight buzzing/crackling type of noise

rounakr94

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Today while I was cleaing the back of the PC, I hear very very faint hissing type of noise from inside the psu.
I thought it was the power cable issue so I changed it out to a Corsair UK flat type cable but still I hear a very very faint hissing.

The psu switch is flipped off and the sound still comes. It only goes away if I pull the power plug entirely.
The sound can be heard only if I put my ears against the exhaust of the psu.

Note: The PSU switch is off but mains power is on and the cable is connected. Only PSU is connected and all other appliances in the vicinity are off. PSU is connected to the UPS which is also brand new APC 1100Va unit.
 

Crowii

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But should coil whine be there if PSU switch is off?
Plus its not exactly like a whine, more like a hiss but very faint and I need to get my ear on the exhaust grill to hear it.
Residual power. The capacitors are still holding a charge, although there's usually some type of resistor to dissipate it. Same reason you get told not to work on the guts of PSUs if you don't know what you're doing, you'll just be zapped with a good amount of volts.

Going back to phone chargers, you will also here it from them for a couple seconds after plugging them out.
 
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Crowii

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From the description, just sounds like coil whine to me. Pretty normal. Shouldn't pose an issue in damn near all cases.

If you have keen ears and a quiet room, then you can hear it from some phone chargers as well.
 

rounakr94

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From the description, just sounds like coil whine to me. Pretty normal. Shouldn't pose an issue in damn near all cases.

If you have keen ears and a quiet room, then you can hear it from some phone chargers as well.
But should coil whine be there if PSU switch is off?
Plus its not exactly like a whine, more like a hiss but very faint and I need to get my ear on the exhaust grill to hear it.
 

Crowii

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But should coil whine be there if PSU switch is off?
Plus its not exactly like a whine, more like a hiss but very faint and I need to get my ear on the exhaust grill to hear it.
Residual power. The capacitors are still holding a charge, although there's usually some type of resistor to dissipate it. Same reason you get told not to work on the guts of PSUs if you don't know what you're doing, you'll just be zapped with a good amount of volts.

Going back to phone chargers, you will also here it from them for a couple seconds after plugging them out.
 
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But should coil whine be there if PSU switch is off?
Plus its not exactly like a whine, more like a hiss but very faint and I need to get my ear on the exhaust grill to hear it.
There's a snake in the PSU.

As long as the caps in the PSU are still charged, there's still power. Wait to see if the noise goes away after overnight.

Your UPS doesn't come into play because an offline/line-interactive UPS is passive until there is no mains power. Otherwise, it's just passing through mains power.
 
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rounakr94

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There's a snake in the PSU.

As long as the caps in the PSU are still charged, there's still power. Wait to see if the noise goes away after overnight.

Your UPS doesn't come into play because an offline/line-interactive UPS is passive until there is no mains power. Otherwise, it's just passing through mains power.
Shiet, must be a micro snake.
Noise indeed goes away if PSU is off for sometime and doesn't come back on immediately until the pc is switched on.
It starts its sound when pc is turned on and then repeats the cycle.
So why does hissing stop when the cable is disconnected? Is it because ground is also disconnected at the same time and the charge has no where to go?

But One thing is certain for sure, the Lockdown increased my OCD by 10x \(゚ー゚\)
 
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rounakr94

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Oh and another thing that I forgot to say is that the sound goes away instantly when I turn off the ups/mains power but it doesn't go away if I turn off the switch on the back of the psu. Is this a whine of some sort?

Here is a video from YouTube with similar sound albeit a bit louder than mine. Incidentally this is also on a Focus Series PSU which is the OEM of my Antec PSU.
View: https://youtu.be/W6ozCZZxg1E

Here is another similar sound coming from a Corsair Ax1200i:
View: https://youtu.be/dMRZIEXhds8
 
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Oh and another thing that I forgot to say is that the sound goes away instantly when I turn off the ups/mains power but it doesn't go away if I turn off the switch on the back of the psu.
Ah... Then the switch on the PSU may be faulty. The switch on the back should do the same thing as unplugging the PSU or turning off the UPS. It should kill all power to the PSU. Ground is present even if you turn off the UPS, so it shouldn't be a ground issue.
 
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rounakr94

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Ah... Then the switch on the PSU may be faulty. The switch on the back should do the same thing as unplugging the PSU or turning off the UPS. It should kill all power to the PSU. Ground is present even if you turn off the UPS, so it shouldn't be a ground issue.
The switch is okay. The sound is now not there even after PC is turned on and shutdown,looks like it was some sort of stray capacitive charge. Hope its okay to use the PSU like this as all else works fine.
 

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