PSU Buzzing Randomly - Cooler Master V750

[roycsc89]

Hi there, sorry if this is in the wrong category. First time posting here

PSU Model: Cooler Master V750

The buzzing sounds like the youtube link here, made by someone else: Youtube

Symptoms

• - Buzz timing: Random, except for 1 case. Will elaborate later
  - Buzz volume: 2 types, soft buzz as the linked video, another louder version that is audible over conversation
  - Possible to even buzz when its just connected to the power source while turned on (the switch behind the PSU). Please note that the PSU is not connected to any parts of the PC. So I'm pretty confident that it is not due to PC hardware setup. Buzz will stop when the switch behind the PSU is turned off though.
  - Buzz will go into the loud version whenever I on my electric shower with water flow 100% of the time. It will also go back to soft version or become silent whenever the water flow is stopped.

I know its a long post, please bear with me

Wiring Layout

• - There are 2 wall sockets in my room. Socket A and B.
  - Socket A is where the water heater wiring seems to feed into.
  - Socket B is where the air conditioner feeds into. (At least I think it is as the wiring cover goes into the wall below the sockets for points A and B)
  - Surge protector using point A. Connected are 2 desktop 2 LED monitors. I dont think the devies are related though as it can buzz when everything else is disconnected.

Almost done. 1 last section 😀

Troubleshoot Findings

• - Air conditioning in the same room does not affect the PSU in on/off state.
  - No buzz for a 1 time test with 2 desktop and one 2100W vacuum cleaner turned on on the same surge protector
  - Same issue with sockets A and B with or without surge protector.
  - Don't think it's the PSU's fan as there are many instances where the fan is spinning and its silent.
  - Have already RMA and got a replacement unit and still having the same issue.
  - Both PSU are new. Noticed symptoms on the 1st day for both units of V750.
  - Second desktop with a cheap 300W PSU sharing the same surge protector is super silent at all times. I have already tested the PSU alone without anything sharing the power with same result.
  - Will buzz with the electric shower scenario with either socket A or B when the water flow is release, with the power for the shower unit on, of course. Just for clarification, water flow without power to the shower unit will not trigger the loud buzz.
  - Does not relate to PC hardware load.
  - Electric quality is decent, never had a blackout in half a year since I moved in.
  - No audio hum so I dont think its a ground loop issue. Not sure on this.

Just for emphasis, the buzzing will either be non-existent, soft or loud in totally random situations except for the electric shower scenario where it will 100% be loud.

Will really be glad if there is someone who knows what strings are the ghost pulling in my room.
Thanks 😀

Sincerely,
Desperately Confused

 

[ko888]

In that video it sounds like loud coil whine to me.

 

[roycsc89]

In that video it sounds like loud coil whine to me.

Oh is it? I'm not an expert at it but what I keep hear from you tube, I would say coil whines are much much higher pitch. Correct me if im wrong

The 1st unit was send back to china and the QA team reported no issue though. how sad. Hoping for more input

 

[westom]

Oh is it? I'm not an expert at it but what I keep hear from you tube, I would say coil whines are much much higher pitch. Correct me if im wrong

Each poiwer supply creates a unque high frequency so that 60 Hz is converted to zero Hz (rock solid and stable) DC voltages. That coil whine may be defined by the unique frequencies used in that particular PSU design.

Coil whine can change due to changing frequencies in a PSU, change of current, and numerous other reasons. It is a most likely but not only possibility.

 

[roycsc89]

Oh is it? I'm not an expert at it but what I keep hear from you tube, I would say coil whines are much much higher pitch. Correct me if im wrong

Each poiwer supply creates a unque high frequency so that 60 Hz is converted to zero Hz (rock solid and stable) DC voltages. That coil whine may be defined by the unique frequencies used in that particular PSU design.

Coil whine can change due to changing frequencies in a PSU, change of current, and numerous other reasons. It is a most likely but not only possibility.

Hi westom,

Thanks for your input.
So this means that it shouldn't supposed to buzz, no matter if the ac source is clean or not? (thats what i think so too)
As long as the voltage range fulfills the products requirement, it shouldn't buzz, is that correct?
So its nothing to do with my home wiring or electric water heater?

 

[westom]

So this means that it shouldn't supposed to buzz, no matter if the ac source is clean or not? (thats what i think so too)

We would wind coils. Then put them into a vacuum chamber. Then enter a varnish. The varnish should lock wires together so that magnetically induced vibrations did not move those wires. Still, sometimes one part of one wire would not stick. Unfortunately, sometimes a coil would vibrate (whine) because the varnish did not always stick to every part of every wire. It happens. You would think the vacuum causes varnish everywhere in the coil And still it sometimes does not stick every part of every wire together.

 

[roycsc89]

@westom,

Oh I see.. So its the luck of the draw...
But still it seems that this issue only happens in my house. And there are some people complaining many years using different brands of PSU on the internet and it all buzz in that house but not other people's home. I am unable to make it buzz at the retailers store.

Should I worry about it? I'm starting to think that either my electric heater wiring or house wiring is faulty or I am just overthinking @@
Please advice thanks ^_^

 

[westom]

Should I worry about it? I'm starting to think that either my electric heater wiring or house wiring is faulty or I am just overthinking @@
Please advice thanks ^_^

Buzzing would be frequency dependent. The frequency (AC line noise) to 'buzz' the wire in one house may not exist in another. Meanwhile, your replies were based on your observation that this buzz was from coils. If buzzing comes from something different, then the validity of that reply may change.

Buzzing coils are mostly a nuisance. In some cases (depending on which coils), a series mode filter on AC power might eliminate the noise frequency that is 'tuned' to that coils. Or a slight voltage change might cause the computers internal regulator to change frequency. To say more really requires more information. In most cases, it is a nuisance - not a human or hardware threat.

 

[roycsc89]

@westom

Thanks for the threat clarification. Now I feel better showering hahaha.

hmmm so all in all, what I can get is that I just picked an unlucky PSU with coil whine that unable to function silently with my home AC frequency... Funny that a cheap 300W PSU beats Cooler Master V750 in the noise department =_=

My landlord will be arranging an electrician to "pull" another wire for the electric shower, whatever he means by pulling. He says 100% will not buzz my PSU anymore. I shall wait and see the results either tomorrow or next week. Will keep you guys posted.

P.S. will edit first post, changing "water heater" to "electric shower" for comprehension accuracy