MP 6,1 Mac Pro 6,1 (2013) - Power supply - Buzzing sounds

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
Hello,

I have owned a Mac Pro 5,1 before and could hear some buzzing sounds from it. At that time I concluded that it had to come from the power supply. I'm pretty sure it wasn't coil whine from the GPU.

Now I have a Mac Pro 6,1 and can hear some buzzing sounds as well. I stuck my iPhone down to the trashcan and recorded the sound :)


Anyone with the same kind of noise?
 

philgxxd

macrumors regular
Feb 11, 2017
231
184
Malaga, Spain
No but it sounds to me like electrolyte capacitors going bad in an switching power supply making these kind of high pitch sounds.
 

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
possibly a problem with the electricity supplier?
Can you elaborate a bit? It shouldn't be a problem with the electricity supplier or I at least don't have any other problems that could indicate that something is wrong.
- - Post merged: - -

No but it sounds to me like electrolyte capacitors going bad in an switching power supply making these kind of high pitch sounds.
I really don't hope so. I understand the whole coil whine thing and problems in laptops and so on, but this sound has nothing to do with gaming and really overloading the GPU :(
 
Last edited:

xtrem

macrumors member
Apr 22, 2009
49
1
@MikkelAD Did you find an answer?

My 6,1 has a sound like there is old school hard drive inside, writing/reading. Nothing to do with high CPU usage and not a constant sound.
And I hear it even when then fan is 100%, so I don't think it is a noice from the fan either..
 

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
@MikkelAD Did you find an answer?

My 6,1 has a sound like there is old school hard drive inside, writing/reading. Nothing to do with high CPU usage and not a constant sound.
And I hear it even when then fan is 100%, so I don't think it is a noice from the fan either..
I tried different things and sadly without luck. I asked 4-5 other people that live in the same country(I live in Denmark) and they didn't experience the same thing. Considering that I had the same problem with the Mac Pro 5,1 I have concluded that it must be some kind of noise on the power lines in the house I'm living in at the moment.

I'm planning on taking the computer to a family member's house one day and test it...
 

uller6

macrumors 6502
May 14, 2010
304
200
I had similar noise issues with my 6,1 quad core before I sold it. When I first had the machine, high CPU loads would cause coil whine from the power supply. I think Apple fixed this behavior with 10.12, but then I started to get bad coil whine from SSD writes. I always had my machine connected to a UPS so in my case I don't think it had anything to do with dirty power.
 

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
I'm planning on taking the computer to a family member's house one day and test it...
Sadly that didn't work, so I think "dirty power" can be excluded.

No but it sounds to me like electrolyte capacitors going bad in an switching power supply making these kind of high pitch sounds.
I took the chance and invested a little money and quite some time. I examined the power supply board:

Power supply board.jpg


I thought to myself that maybe the two capacitors marked with red could be the "problem". I found some new ones with the same specs but a better quality and the project became real:

IMG_0354.JPG


IMG_0355.JPG
IMG_0353.JPG


3 hours later and sadly my effort didn't solve anything. The exact same high pitch noise is present. I have a pretty good hearing and the Mac Pro is about 1m away from me. Some would say "place the computer further away" and that is a solution, but I think the machine is beautiful and want it placed on my desk. I'm planning on keeping this baby for a while 🙂

I have thought about buying a new power supply board since it isn't that expensive, but honestly I don't think it will solve the problem or at least forever. One thing I'm pretty frustrated about is that only very few people have reported something similar. I would really like to know if it's a production error, an age related thing or many people just don't hear it when they are close to the machine because they got all kinds of other equipment that make noise.

At this point I think I must give up 😔 Oh well, at least I gave it a good try...
 
Last edited:

MisterAndrew

macrumors 68000
Sep 15, 2015
1,975
1,523
Portland, Ore.
It would be interesting to know what causes it. All three 6,1s I've had make the sounds a little. My quad-core/D300 (2016 build date) was the most quiet. It would almost never make sounds, but occasionally you could hear it if you put your ear up close. My 6-core/D500 (2014 build date) is the most noisy. Sounds like little birds chirping coming from the power supply area. You can't hear it more than a foot or two away though so it's not that annoying. My 8-core/D700 (2017 build date) makes some noises too. Interestingly, when I temporarily put an SSD into the quad-core from a MacBook Pro it got really noisy. Soon after that the SSD bit the dust. That was after I put it into an OWC Envoy Pro enclosure which corrupted it. So you might want to switch SSDs to see if it helps.
 

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
It would be interesting to know what causes it. All three 6,1s I've had make the sounds a little. My quad-core/D300 (2016 build date) was the most quiet. It would almost never make sounds, but occasionally you could hear it if you put your ear up close. My 6-core/D500 (2014 build date) is the most noisy. Sounds like little birds chirping coming from the power supply area. You can't hear it more than a foot or two away though so it's not that annoying. My 8-core/D700 (2017 build date) makes some noises too. Interestingly, when I temporarily put an SSD into the quad-core from a MacBook Pro it got really noisy. Soon after that the SSD bit the dust. That was after I put it into an OWC Envoy Pro enclosure which corrupted it. So you might want to switch SSDs to see if it helps.
That is definitely some very interesting observations and with three machines I can't imagine someone with more experience :)

Since you have different configurations with different manufacture dates I think we can conclude that the possibility is present with all Mac Pro 2013.

This is the sound that I'm talking about which is recorded with my iPhone placed down in the top of the computer:


I'm glad that your can hear it too, but it still surpises me that so few seems to "know" about it or can simply hear it.

I think my machine is from early 2015 and I bought it used. It was very minimal used and I don't use it for professionel work. I simply use it a my personal computer.

Something tells me that the power supply maybe "wears" over time but then again I think it would be weird considering the minimal use of mine.
Anyone can write "ac" in terminal and see "powered on time" and mine shows "3854 hours" which is quite low?

I have a difficult time letting this go since I want to keep this computer. In my mind it isn't likely that the noise would come from a SSD or the GPU's(since the sound is present all the time and therefor under very easy load)

Since a new power supply board isn't that expensive I took the chance and ordered from china via eBay. I live in Denmark so it will probably take 2-3 weeks before arrivel and especially in these covid-19 times.

I will of course come back with my results when I have installed the new power supply board!
 

edanuff

macrumors 6502
Oct 30, 2008
325
81
I believe that sound is called “coil whine”. I had an nMP that produced that noise and was able to get it exchanged back when it was under warranty. Not sure what caused it.
 

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
I believe that sound is called “coil whine”. I had an nMP that produced that noise and was able to get it exchanged back when it was under warranty. Not sure what caused it.
Yes, "coil whine" is most likely the expression people will use about such a sound. In most cases though it's about the GPU making noise in some gaming machines when it's being pushed and producing a ton of FPS.

Since this is a Mac Pro with D300's and the sound already is present on the desktop(practically zero load) I have concluded that it can't be the GPU's.

Therefore it must be the PSU hence why I have bought a new power supply board. There is of course a chance that it won't solve anything and at that point 2020 will be even more sad than it already has been!
 

KeesMacPro

macrumors 6502
Nov 7, 2019
254
56
I found some new ones with the same specs but a better quality
You bought the RollsRoyce of the capacitors...
Nichicon is very reliable and may work for decades without failure.
It's a pity it didn't solve anything.

From my own experience I assume the noise comes from the usual suspects:
-the transformer
-the diodes
-the coils

If you could test the PSU (under load) externally, with some extension cables soldered, you could identify the sources, but this may not be practically doable...
If you can, you'll find the components easily, and could replace them for a better quality one, or (depending on the heat it generates!!) desolder and mold the noisy components into epoxy (synthetic resin) and solder them on the PCB again..

I hope the new replacement PSU solves the issue.
 
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MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
You bought the RollsRoyce of the capacitors...
Nichicon is very reliable and may work for decades without failure.
It's a pity it didn't solve anything.

From my own experience I assume the noise comes from the usual suspects:
-the transformer
-the diodes
-the coils

If you could test the PSU (under load) externally, with some extension cables soldered, you could identify the sources, but this may not be practically doable...
If you can, you'll find the components easily, and could replace them for a better quality one, or (depending on the heat it generates!!) desolder and mold the noisy components into epoxy (synthetic resin) and solder them on the PCB again..

I hope the new replacement PSU solves the issue.
Reporting back!

I received the power supply earlier than expected. Apparently it was shipped with DHL Express. I could first get to the project today and the results was sadly disappointing. Replacing the power supply didn't solve anything 🙁
I guess that is more or less 170USD down the drain...

I simply can't imagine that either the SSD or the GPU's are making any noise 🧐 Something tells me that all Mac Pro 2013 models more or less have this "problem". It seems like I'm just really sensitive to those sounds.

On the bright side I got a new power supply and changed the thermal paste on both GPU's in the proces.

Oh well, the project was fun and I had to try :)
 
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MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
Interesting. So it remains a mystery. I guess you could buy another Mac Pro to see if you can find one that is more quiet.
From your description it seems I'm not the only one who can hear something, so I guess there is really nothing to do. It's not a high sound but I must be a bit sensitive to it + I'm sitting really close to the Mac Pro.

I don't use this Mac Pro for professionel work and I don't need a really powerfull computer for my everyday tasks. I just happen to be a little interested in technology and Apple. The Mac Pro 2013 appealed more to me than eg. a Mac Mini :)
 

xtrem

macrumors member
Apr 22, 2009
49
1
I have already tried to switch SSD (apple original vs Samsung 980 EVO). Sound is still there...
 

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
I searched around the internet about "SSD noise" and saw this explanation:


I really didn't think that a SSD had any potential noise connected to it. My plan is to remove the SSD and try boot from an external drive via USB and see if that does anything.

I have already tried to switch SSD (apple original vs Samsung 980 EVO). Sound is still there...
That does not sound promising. It seems like it isn't even worth it for me trying to change the SSD after your experience...

At this point it seems that the sound most likely is comming from some capasitors from the motherboard which of course is a lost cause 🙁
 

xtrem

macrumors member
Apr 22, 2009
49
1
I’ve tried with an external samsung 840 in usb housing. No difference.

but in the dell article it also mentions connected usb-accessories. Anyone tried without any cables (or minimal)?

without Ethernet? Im using dual ethernet cables.

I’m also thinking motherboard....
 

MikkelAD

macrumors regular
Original poster
Feb 17, 2018
152
10
I’ve tried with an external samsung 840 in usb housing. No difference.

but in the dell article it also mentions connected usb-accessories. Anyone tried without any cables (or minimal)?

without Ethernet? Im using dual ethernet cables.

I’m also thinking motherboard....
Just reporting back for the few interested :)

I did the final tests today. I took the standard SSD out and tried to boot from another drive connected by USB. To me the noise was more or less the same 🙁

I did some further testing after the standard SSD was installed again. Interestingly enough using "Blackmagic Disk Speed Test" resultet in even more noise than I'm used to and the noise came back to "normal" as soon as the test stopped.

To me this indicates that when the SSD demand more power during extensive read/write the motherboard will deliver and therefor more noise!

At this point the conclusion must be that in most cases noise from a Mac Pro 6,1 must come from the fan(which is obviously fine and expected) and the motherboard when eg. the SSD demand more power(which for me is irritating)

Hopefully this will spare a few people for frustrations in the future...
 
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