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  1. #1
    Mac Pro 2012 Random ďSnapĒ Sound
    Hi there,

    I know its probably a long shot, but I thought Iíd create this post just in case anyone might be able to help shed any light on this situation or if perhaps anyone else has come across this same problem before.

    For a few months now my Mac Pro has been producing a random snapping sound. It can sometimes occur just once or multiple times a day and isnít triggered by a specific thing. It is a one time ďsnapĒ and isnít like a sequence of snaps in a row if that makes sense. Its not necessarily a loud snap, but Iíd consider it louder than HDD clicking. If I had to guess, I think the problem might have started after an internal clean a few months ago with a vacuum cleaner and compressed air (the same way Iíve cleaned this and many other systems throughout my entire life so far, so would be very surprised if this has caused the issue).

    The operation of the Mac is as good as its ever been so I canít see any degradation in performance, increase in random kernel panics (I canít remember when I had one last) or anything that would clearly suggest there is something actually wrong.

    I have completely removed the drive bays (including super drives) and have gone as far as purchasing a brand new SSD to rule out possible signs of HDD failure to no avail. I have tried altering the fan speeds to see if that helps to identify any issues but this has not influenced the snapping sound in any way. I have gutted the PC and cleaned the components from top to bottom to rule out dirt and dust and I could not identify anything on any of the boards that might suggest damage. Besides the replacement SSD mentioned as a means of troubleshooting, there have been no other hardware changes since originally purchasing the Mac in 2012.

    For the next step, Iím trying a different power cable plugged into a different outlet for a few days to see if that rules out possible power issues.

    Though the next step might involve sticking a microphone in the case to try and locate the snap, I am actually at a loss for what to do next. Iím not 100% sure on this, but the snap appears to emanate from the front of the Mac.

    I appreciate any help I can get at this point.

    Kind Regards,
    Matt

  2. #2

    rachalmers's Avatar
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    Mac Pro 2012 Random ďSnapĒ Sound
    Quote Originally Posted by Nanco View Post
    Hi there,

    I know its probably a long shot, but I thought Iíd create this post just in case anyone might be able to help shed any light on this situation or if perhaps anyone else has come across this same problem before.

    For a few months now my Mac Pro has been producing a random snapping sound. It can sometimes occur just once or multiple times a day and isnít triggered by a specific thing. It is a one time ďsnapĒ and isnít like a sequence of snaps in a row if that makes sense. Its not necessarily a loud snap, but Iíd consider it louder than HDD clicking. If I had to guess, I think the problem might have started after an internal clean a few months ago with a vacuum cleaner and compressed air (the same way Iíve cleaned this and many other systems throughout my entire life so far, so would be very surprised if this has caused the issue).

    The operation of the Mac is as good as its ever been so I canít see any degradation in performance, increase in random kernel panics (I canít remember when I had one last) or anything that would clearly suggest there is something actually wrong.

    I have completely removed the drive bays (including super drives) and have gone as far as purchasing a brand new SSD to rule out possible signs of HDD failure to no avail. I have tried altering the fan speeds to see if that helps to identify any issues but this has not influenced the snapping sound in any way. I have gutted the PC and cleaned the components from top to bottom to rule out dirt and dust and I could not identify anything on any of the boards that might suggest damage. Besides the replacement SSD mentioned as a means of troubleshooting, there have been no other hardware changes since originally purchasing the Mac in 2012.

    For the next step, Iím trying a different power cable plugged into a different outlet for a few days to see if that rules out possible power issues.

    Though the next step might involve sticking a microphone in the case to try and locate the snap, I am actually at a loss for what to do next. Iím not 100% sure on this, but the snap appears to emanate from the front of the Mac.

    I appreciate any help I can get at this point.

    Kind Regards,
    Matt
    I know this. Itís the hard drive parking. Some drives have built in sleep mode on the drive. Itís not to do with the computer, just the drive.
    Now. When the drive wakes up... it proceeds, but when parking again... snap.
    Iím not sure if itís damaging the drive and you can get a bit of software that stops it. Overrides the drive code.
    Itís a Ďfeatureí of some drives. Not all.
    I got rid of mine in the end. Didnít want a failed drive in the middle of something

    But... with no hdd, it sounds like a capacitor discharge. And they are not just on the main board, but the power supply is the main culprit.


    Sent from my iPhone using Mac-Forums

  3. #3

    pigoo3's Avatar
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    Two thoughts:

    1. Could be the beginning of the power supply going bad (partial failure)...but usually you don't hear that many "SNAPS" before a PS dies...usually it's one BIG POP...followed by some stinky smoke.
    2. Here's a crazy idea...maybe your Mac Pro is acting like a bug-zapper.

    Maybe the occasional bug (spider, moth, fly, ant, mosquito, etc.) is getting in there...finding something highly charged...and getting ZAPPED!

    - Nick
    - Too many "beachballs", read this: Beachballs
    - Computer seems slower than it used to? Read this for some slow computer tips: Speedup
    - Almost full hard drive? Some solutions. Out of Space
    - Apple Battery Info. Battery

  4. #4

    rachalmers's Avatar
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    Hmm. So what else is on the same power circuit as the Mac? A fridge, stove, aircon or something else thatís switching on/off. A cloths iron?
    Something thatís developed arcing in its switching. The resulting arc surge will be heard in the speaker as the EMF hits it.
    and wonít do your Mac any good either.
    Doesnít even have to be the same plug, just near enough is all it needs.



    Sent from my iPad using Mac-Forums

  5. #5
    Quote Originally Posted by rachalmers View Post
    But... with no hdd, it sounds like a capacitor discharge. And they are not just on the main board, but the power supply is the main culprit.
    I actually had the power supply open just a couple of days ago and didnít notice any bulging capacitors or points of interest. I havenít heard any sounds coming from the power supply itself, though I could swap it with the one from my backup system for a few days to help with troubleshooting. Thanks for the suggestion!

    Quote Originally Posted by pigoo3 View Post
    Here's a crazy idea...maybe your Mac Pro is acting like a bug-zapper.
    Haha! If that is the case, then the poor victims are incredibly courteous as not to make a mess inside my computer. Unless theyíre disintegrated on impact then I donít think this is the cause sadly. Great suggestion though!

    Quote Originally Posted by rachalmers View Post
    So what else is on the same power circuit as the Mac?
    The Mac is usually plugged into a power strip that is shared with some of my outboard gear, preamps, speakers etc. This strip is then plugged into the outlet.

    My area is audio engineering so I have to be attentive to noise isolation and ensuring my gear is properly powered at all times. I havenít noticed any interference in other gear that shares this power strip, however as of today I have bypassed that altogether and plugged the Mac directly into the outlet with a different power cable. So far, so good (touch wood) but it is still early days. Iíll only know for sure after a few days if this really has narrowed the problem down.

    As for interference from other appliances in the building, I cannot say for sure without doing a full audit. As far as Iím aware, there are no other things interfering with the electrics right now as it would most likely be audible through the speakers first.

  6. #6

    pigoo3's Avatar
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    Quote Originally Posted by Nanco View Post
    The Mac is usually plugged into a power strip that is shared with some of my outboard gear, preamps, speakers etc. This strip is then plugged into the outlet.

    My area is audio engineering so I have to be attentive to noise isolation and ensuring my gear is properly powered at all times. I haven’t noticed any interference in other gear that shares this power strip, however as of today I have bypassed that altogether and plugged the Mac directly into the outlet with a different power cable. So far, so good (touch wood) but it is still early days. I’ll only know for sure after a few days if this really has narrowed the problem down.
    Is it possible the snap or pop is coming thru the Mac Pro's speaker...in reaction to something to do with your audio equipment...or like member rachaimers mentioned, something electrical on the same circuit (and coming thru the Mac Pro's speaker)?

    - Nick
    - Too many "beachballs", read this: Beachballs
    - Computer seems slower than it used to? Read this for some slow computer tips: Speedup
    - Almost full hard drive? Some solutions. Out of Space
    - Apple Battery Info. Battery

  7. #7
    Quote Originally Posted by pigoo3 View Post
    Is it possible the snap or pop is coming thru the Mac Pro's speaker...in reaction to something to do with your audio equipment...or like member rachaimers mentioned, something electrical on the same circuit (and coming thru the Mac Pro's speaker)?

    - Nick
    The sound is handled by an Apogee Ensemble interface via firewire which then sends the audio to my external speaker set up. This is the default I/O device so the internal Mac speaker is not actually used besides for the startup chime.

    After isolating the Mac from the power strip yesterday, all was well until about midnight when I had two snaps within the space of about 10 minutes of each other. Nobody else was around at that time and no other electrical appliances were in use in the building to my knowledge.

    Today Iíve gone one step further and basically unplugged everything apart from the essentials (mouse, keyboard, one screen) and Iím also powering the screen independently from my outboard equipment. The main outboard power cable is unplugged and the switch turned off. Within the first maybe 10 minutes of the machine being turned on, I had about two or three snaps.

    Iím not completely ruling it out, but Iím not entirely convinced that the problem is anything to do with what is going on outside of the Mac at this stage. The next thing Iím probably going to do is inspect the fans including the graphics cards and maybe try disconnecting one at a time to see if that helps to locate the snapping source.

    I donít know if its at all possible to give an accurate answer, but how long should I leave the Mac turned on with one of its fans removed? Obviously temperatures will be affected, but considering the random nature of this snap, Iím not sure that I would want to have a fan removed all day waiting for the snap to occur if there is sign of it damaging the computer in any way.

    On a side note, the power supply fan appears to be emitting a low whirring sound (the pitch is roughly 40hz at around 600-650 RPM). Funnily enough I donít recall this fan being so noticeable even when idle and under no major load (I've just lived with it for a while). Could this be linked with my problem or just something entirely different? Is it worth investing in a replacement?

    Thank you both for your help so far. I'm determined to get to the bottom of this.

  8. #8

    pigoo3's Avatar
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    Quote Originally Posted by Nanco View Post
    The sound is handled by an Apogee Ensemble interface via firewire which then sends the audio to my external speaker set up. This is the default I/O device so the internal Mac speaker is not actually used besides for the startup chime.
    I only mentioned the "Mac Pro's speaker" since I didn't 100% know if you had external speakers connected. My point was...could the snapping/popping noise be coming thru whatever speaker is being used by your Mac Pro...due to some sort of electrical surge/noise on the home wiring. Sounds like you're saying no.

    Quote Originally Posted by Nanco View Post
    I don’t know if its at all possible to give an accurate answer, but how long should I leave the Mac turned on with one of its fans removed? Obviously temperatures will be affected...
    I wouldn't fool around with the computers cooling system. Finding out the source of the snapping/popping isn't worth possibly damaging the computer (bad return on investment).

    I would stick to more traditional & creative ways to try to troubleshoot & isolate things. I think disconnecting everything external is a great start...and personally I would pay close attention to the power supply area for the snapping/popping sounds.

    But of course trying to more closely isolate where the popping/snapping is coming from is the most important...since that will allow to to focus much more on a specific area of the computer...and only consider the parts in that area that might be making the sound.

    I don't know where you have your Mac Pro located. But if it's on the floor next to you...might be better to place it on your desktop...or on a chair or table right next to you (same height)...so when the sound happens...when you hear it...you can better determine what part of the Mac Pro case the sound is coming from.

    - Nick
    - Too many "beachballs", read this: Beachballs
    - Computer seems slower than it used to? Read this for some slow computer tips: Speedup
    - Almost full hard drive? Some solutions. Out of Space
    - Apple Battery Info. Battery

  9. #9

    rachalmers's Avatar
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    Interesting problem.:-) Lets see. Do you still get the sound if the computer is somewhere else? I mean, unless you live in a one room apartment. Put it in another room.
    Is there any ozone smell generated with the snap? (Electrical)
    How loud is it? You can hear it across the Room? Across the street?
    A wireless transmitter near you? Ham radio type thingy. They can cause mayhem if the antenna isnít tuned properly. I once had a bare speaker sitting on a window sill not connected to anything, and the neighbours ham radio transmissions were coming through it, until I told him.
    Which is why I mentioned it a few posts back. A speaker doesnít have to be connected to anything to be able to pick up emf, if itís a traditional moving coil speaker. Piezo of course doesnít do it. Your audio equipment wonít pick up that stuff because itís almost certainly shielded and earthed perhaps. I donít think Iíve ever seen a computer with shielding.
    Do you have it plugged into a surge protector? Even better a battery standby. A UP, an uninterruptible power supply.
    Letís face it, the only thing that can create a snap like you describe is metal moving. Expansion/contraction, or something electrical discharging. If your speaker is disconnected will you hear it. If so... itís one of those two. The case or some part of it heating up and snapping as it cracks into place, or something arcing. In which case you will smell the ozone. Unless you are a smoker then of course youíll be lucky to smell anything!



    Sent from my iPad using Mac-Forums

  10. #10
    Quote Originally Posted by pigoo3 View Post
    I don't know where you have your Mac Pro located. But if it's on the floor next to you...might be better to place it on your desktop...or on a chair or table right next to you (same height)...so when the sound happens...when you hear it...you can better determine what part of the Mac Pro case the sound is coming from.
    Iíve done this now and I fear it might have raised more questions than solutions. That said, my Mac has been good for the past 24 hours and I have only had one instance of the snap which I think is actually coming from the graphics card (possibly the fan?). I noticed when I loaded a game that the fan began to speed up and its almost as if the snap occurred at each stage of the fan speeding up. When it reached a consistent speed, I didnít hear any further snaps.

    Iíll be keeping an eye on things over the weekend and will post if I notice this snap coming from anywhere else in the Mac. With what I noticed so far, I can confidently say that I didnít notice anything visual to accompany the snap like arcing or lights.

    I do have some further questions about the graphics card/s in my Mac, however I might create a separate thread for that later as not to go too far off topic. I did notice some things about the power supply and the fan (I mentioned the latter in my last post).


    Quote Originally Posted by rachalmers View Post
    Interesting problem.:-) Lets see. (snip)
    I have a Mac Pro 2008 model that I use as a backup and for extra storage. Iíve since learned that I canít simply swap out the power supply from this Mac to my 2012 one, however one thing I noticed was just how quiet the actual power supply was in comparison to the one in my 2012 Mac Pro. Here is a short video to hopefully better explain the sounds coming from the fan and the back of the power supply:

    PSU Fan Hum and PSU Buzz.mp4 - Google Drive

    I swapped the power plug from the 2008 Mac and plugged it into my 2012 Mac (same outlet and same plug with nothing else external plugged into the mac). The 2012 power supply was still quite noisy. I also tried plugging into a surge protector strip and Furman power conditioner, neither of which affected the noise.

    The higher pitched noise is not as noticeable when the Mac is under my desk, however Iím actually curious if this sound is considered normal or if its the sign of a failing power supply. It doesnít appear to be interfering with my outboard equipment, so I can only assume this sound is isolated to the Mac and is not caused by anything external (especially considering my other Mac is silent in comparison). I also have no idea how long this noise has been present as it is drowned quite well under the desk and especially with whatever is coming through my speakers drowning it even further.

    I havenít experienced any other signs of possible power supply failure, however what do you think? I have not noticed any smells coming from the Mac or around the power supply area (non-smoker, my sense of smell is very good. I can smell food from over a mile away), but the low fan hum is definitely noticeable when the side is on and the case is under the desk. Could the fan be on its way out also?

    In case I do need a new power supply (do they even exist?), I would be interested in where I can get one from or if non-Apple branded power supplies exist (like Newertech or similar). Preferably UK/EU based if possible.

    Once again, many thanks for all the help so far.

  11. #11
    I thought I’d just give a quick update on the situation.

    Firstly, I removed both graphics cards from the Mac and did some tests by running just one at a time to see if there were any differences. Firstly, I noticed that there were no differences performance wise (under heavy load and idle), however one of them was running considerably hotter than the other.

    The cooler card seemed to run fine however I noticed that the warmer card “snapped” a bit (due to rise/fall in temperatures perhaps?), therefore I’m assuming that this card may be the source of the problem.

    I used to originally use 4 screens however I have been using 3 for about a year now, therefore I won’t have any use for the second graphics card anymore. I’ll check the thermal contacts and do some more testing when I have time, but for now I’m proud to confirm that I have a snap free Mac.

    The problem (?) with the PSU still persists, however I’ll create a new thread for that as not to go to far off topic.

  12. #12

    chscag's Avatar
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    You can continue with this thread if you have any further problems that include the power supply. This way we will have a history of all that occured in one place.

    Thanks.

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