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iMac (4K, 21.5", SSD, 2017) making wierd noise? Help!

S

swealpha

macrumors regular
Original poster
Feb 5, 2017
106
17
Hello!

My new iMac has started making some wierd noise, I got it 1 week ago and I didnt noticed this until today.

I dont hear it always, it comes and goes sometimes. I think when scrolling.


It reminds of a 2.5" 5,400rpm HDD noise when working.


My system details:
iMac 4k
3,4 GHz Intel Core i5
16 GB 2400 MHz DDR4
Radeon Pro 560 4 GB
APPLE SSD 250GB (SM0256L)



What do you guys think it could be?



Thank you!

(This is my first iMac, I had a macbook pro mid 2014 ssd before this.)

Alternative with better microphone: https://instaud.io/1Rlf
 
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Do you guys think it could be worth to buy a UPS? Maybe it will help to remove the coil whine?

I live in Sweden so the electricity-standard should be kinda ok.. but i dunno, maybe it is not.
 
swealpha said:
Do you guys think it could be worth to buy a UPS? Maybe it will help to remove the coil whine?

I live in Sweden so the electricity-standard should be kinda ok.. but i dunno, maybe it is not.
Click to expand...
You could try your Mac in a different outlet and see if it goes away? Sometimes the electrical fixtures go bad. I’ve experienced it more than once where I live now. Had a can light fixture that would blow through bulbs in a day.
 
swealpha said:
Do you guys think it could be worth to buy a UPS? Maybe it will help to remove the coil whine?
Click to expand...

The coil whine is not from your power line. It is from the computer's own switching power supply. Some internal component wasn't glued or soldered down properly.

Cool story: In a land and time far far far away, I was a summer intern working on a switching power supply running a large motor. The boss's power supply controller was all analog - and the device shrieked constantly. I replaced the controller with an all digital one run by a microprocessor. With a constant motor load, there was now total silence, even though the supply was switching away at 20KHz. With a varying load, a 1KHz SHRIEK!!! filled the lab - my software recomputed the 20KHz duty cycle every millisecond. Conclusion: Coil whine comes from the magnetic components in the power supply having changes in their magnetic fields.
 
This is how it sounds from the back of the iMac.

In the begining and in the end of the audio-file you can hear how it sounds when the microphone is not so close to the imac.

https://instaud.io/1Rlf

This makes me so angry. Because i think this is because i have customized my iMac.
Why do apple not sell iMacs with 16GB ram from stock?

OOhh..
 
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haruhiko said:
I don't think RAM has anything to do with noise.
Click to expand...
Ofcourse not, but if some guy at the applestore opens up the imac from the factory and then tries to install RAM. I think i will not get chocked if he manages to brake something up.
 
swealpha said:
Broken fan I think.
Sometimes I dont hear that sound even due the fan is spinning in high speed.

Wierd, will send this crap 2500USD back. Grr
Click to expand...
Check the fans by increasing the RPM through some app, like fan controller or iStat Menus. If the sound happens at the higher speed then you at least know it is the fans. Also, keep in mind that this Mac does run pretty hot and there will be much more noticeable fan noise than in pre-4k models. (you have only one fan to cool both CPU and GPU) If this is not the cause, higher RPM, then exchange to Apple. See if they can do express replacement where they send you a device and once received you send the defective one back to them.
 
jgelin said:
Check the fans by increasing the RPM through some app, like fan controller or iStat Menus. If the sound happens at the higher speed then you at least know it is the fans. Also, keep in mind that this Mac does run pretty hot and there will be much more noticeable fan noise than in pre-4k models. (you have only one fan to cool both CPU and GPU) If this is not the cause, higher RPM, then exchange to Apple. See if they can do express replacement where they send you a device and once received you send the defective one back to them.
Click to expand...

Thank you for your answer. I am already using smcfancontrol. :) :) Tested.
It is not a normal fan noise, this is something else. Low freq noise or something. (Link: https://instaud.io/1Rlf)

And I don't feel like it is getting to hot if i compare with my mid 2014 MBP.
Running 2x 4k videos from Youtube using Chrome v.64. After 30min, fan speed 1200 rpm and 59C.
So it is very good imo.

My idea is to order a new iMac with the same configuration and send this one back for refund when i get the other one.

- Do you guys think it could be the SSD that makes this wierd noise?
Because I dont think it is the fan.
 
I contacted apple and they asked me what OS i had and if i could reset the SMC etc.

I dont think this sh*it has nothing to do with the ugly coil-whine noise.

I am sooo disappointed at apple.

My plan is to return and order a new one, will i get the same ugly noise again maybe i could try to fix it using some SMC etc, maybe UPS.

Thank you for listening to me :D
 
vddobrev said:
I listened to the recording, and this is a fan noise. Remove your fan control software and see what happens.
Click to expand...

But even when i set my fan speed to maximum or medium that ugly noise is in the background always.

Thank you for your tips.
 
swealpha said:
But even when i set my fan speed to maximum or medium that ugly noise is in the background always.

Thank you for your tips.
Click to expand...
OK, but just remove your fan control software and let the system control it so that you can rule it out. From your system spec, it looks like the fan is the only moving part. All I hear in the recording is a vibrating sound that seems to originate from a moving part, and to me this is not coil whine.
 
vddobrev said:
OK, but just remove your fan control software and let the system control it so that you can rule it out. From your system spec, it looks like the fan is the only moving part. All I hear in the recording is a vibrating sound that seems to originate from a moving part, and to me this is not coil whine.
Click to expand...
This makes me think about, what happens if i take a backup from this harddisk and install it on the new one. I hope i will not get the error with me lol.

Maybe best idea to reinstall the system.

Because, yes i uninstalled the fan controllers but i have no idea if it is 100% uninstalled or 99,9%

Thank you for your tips!!!
 
vddobrev said:
Here is an idea - start in single user mode (Command-S) or recovery mode (Command-R) and let it sit like this for some time, do you hear the noise?
Click to expand...

I will try this, let say i dont hear it in this mode. What can I do then? Reinstall OS? Thank you
 
Do you have 3-pin or 2-pin wall plugs in Sweden?
If it's just 2-pin, could the "hot" and "neutral" be swapped around?
If you plug the iMac into a different outlet elsewhere in the house, does it still make the sound?
 
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Fishrrman said:
Do you have 3-pin or 2-pin wall plugs in Sweden?
If it's just 2-pin, could the "hot" and "neutral" be swapped around?
If you plug the iMac into a different outlet elsewhere in the house, does it still make the sound?
Click to expand...

3-pin. It has started to make this wierd noise again lol, gaaah.
 
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swealpha said:
3-pin. It has started to make this wierd noise again lol, gaaah.
Click to expand...
Noting new in this video, still same vibrating sound. Can you concentrate on the conditions that cause this noise vs no noise? For example:

- leave the computer idle - does it make the noise?
- stress CPU - does it make the noise?
- stress GPU - does it make the noise?
- stress CPU + GPU - does it make the noise?
- turn off WiFi - does it make the noise?
- turn off Bluetooth - does it make the noise?
- turn off WiFi + Bluetooth - does it make the noise?
[doublepost=1520292684][/doublepost]In all honesty, there is nothing productive about this thread. It is confirmed the machine makes noise that you are not comfortable with. What is it that you want to achieve? Your machine is brand new, I do not suppose you will start repairing it yourself, even if we find out what/when makes the noise. Why not just return it and get another one.
 
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