Buzzing noise in iMac(2013) when running on UPS.

Hello,
This is my first iMac 21inch late 2013 model bought 4 days back, Everything seems just fine except one thing - I have a UPS (600VA) Connected to the iMac, when power goes out the system runs on UPS...while running on UPS, I can hear mild buzzing sound coming out of the iMac..I guess from bottom or through speaker hole in the back, buzzing sound is mild but can be heard from distance (4-5 feet) in silent environment. When power comes back...buzzing sound goes away.
I am not sure if the sound is coming from fan or any other hardware..but it is either coming from bottom of the screen or through speaker holes.
What could be the reason? It happens only while it is running on UPS backup.

My first guess would be cheap mike (or...lights, camera noise, etc.) I think you have to spend at least $150 to avoid buzz. If you can't reshoot, try the audio filters in FCP or SoundTrack. They are extensive so I don't think you would need to buy any other program. The ST user's manual lists the filters and what they do.

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Noisy power supply when running of UPS?... follow up post.

Ned/The hatter your input here would be most appreciated along with anyone else using a UPS with your mac pro. Please read on...
Having just concluded a rather detailed any lengthy post over in the power mac g5 forum with regards to loud buzzing noise from the power supply running of battery backup.
I recemmend reviewing the link below for the full and i think interesting read...
Linked here: http://discussions.apple.com/thread.jspa?threadID=665537&tstart=0
To sum it up it concluded that my model of UPS (Belkin) produces a simulated sine wave. I am unsure of technicals here, but this then makes the power supply in powermac G5's make a nasty electrical noise as the unit works to sort it out. What is ideal is a pure sine wave i understand.
The reason for my post was that i was concerned the noise was a sign of harm being done to my mac. No one has said either way yet that this noise is either just a nuisance and it something thats got to be lived or that its actually harming my machine.
Anyhow it turns out that the RS series from APC also makes the G5 powermac make a noise. And i am aware that Ned along with some others use the APC RS series with there mac pro's. What i am looking to find out is... Do you have a noise from your power supplys when running on battery backup with your new shiney mac pro's?
The APC smart ups series however does not make the powermac G5 make a noise this has been confirmed by several users. I guess this is because these models produce pure wave sine.
As you can see this has all got very complicated and over my head.
The reason for me coming into this forum and asking about noisy power supplys when using certain UPS is because shortly i will be switching to a Mac pro. And if the power supplys in these are different and dont make a noise when running under battery with certain APC Rs's and the new Dual form belkin units then i wont return my current belkin model in exchange for a APC smart ups. I will just live it for a short time whilst i own my G5 and just hope it wont do any damage if and when we have a power outage.
Thank you to anyone that can guide or assist me with this dilemma. Cheers Pob

Pobster,
Switching power supplies (such as those used in computers) do not require a "pure" analog sine wave input; they are more than capable of running on PWM/stepped sine wave input. The noise from the power supply when running on power from a PWM output UPS does not indicate that damage is being done to your machine; it's a harmless side effect.
Some equipment will be damaged if powered via PWM input; items with compressors (refrigerators, air conditioners) definitely fall into this category, as well as some medical equipment and telecom equipment.
I live in an area with notoriously dirty power; a UPS is critical in my case (I'd argue that it is critical in any case, however). I've ran my equipment on UPSs for many years, and the price has dropped significantly. I've got one APC SmartUPS with pure sine wave output which was purchased for me by a client, but most of my equipment is running on UPS with PWM output. It's not uncommon for me to have 20-30 power events in a given day - most of them transient voltage drops or spikes; I've still got an old Sun Sparc 10 file server that's still chugging along.
A couple of interesting articles for your perusal:
http://www.macosxhints.com/article.php?story=20051009043816537
http://en.wikipedia.org/wiki/Pulse-width_modulation
A quick google will turn up lots more information on the topic. APC used to have a white paper on their site which talked about this very topic.
Most manufacturers provide connected equipment insurance - tripp lite, for example, provides $250,000(US) coverage. I've never known anyone who actually needed to use this coverage - I certainly haven't .
In brief: A UPS with PWM output will not harm your computer; switching power supplies are more than capable of handling this. If the noise bothers you, look for a UPS with "pure sine wave" output - you will pay more for this feature; it's an aesthetic choice in this case.

Buzzing Noise from (IMAC 27-INCH,MID 2010)

I have noticed this buzzing noise (like crackling electricity of sorts) comign from the left side of the machine out of the cooling vent. I bought my IMAC in 2010 and have not had any problems with it until now. I noticed the "noise" a couple of months back and it would show up here and there every once in a while, it was not annoying, so I let it be. Until this last time, when the noise was loud and annoying, I could not just forget about it. I am under warranty and called into Apple to see what can be done for this problem. I was told to take it into my nearest Apple store to get it looked at, since over the phone they could not do anything about it.
I took it in May 11tt, 2012 and the guys at the Genius Bar were stumped? They had no clue and it was the first time the two gentelmen that helped me heard of this kind of problem! Since there is no moving parts on that side of the computer they escalated the problem "query" to apple engineering and was told it would take a week for a response. Thus far, I have not been updated on my problem or contacted as to the status of my problem. Its been 12 days and will be contacting them to see whats up!
Will update if problem is resolved!
Has anyone had this type of problem?? Any advice would be apprciated!! Thank you

This might seem a strange answer, but it has fixed this fault on my 27" two year old iMac (at least for a few days now, will be monitoring).
I had this very fault suddenly develop last week.   It was consistent, the noise increased with screen brightness, but was also present with the screen asleep.
I looked at every forum on the subject, became almost convinced my fans weren't controlling properly as well.
I decided it was the switched mode power supply, discussed repair options with my local Apple Store.
Checked the household mains voltage - I'm in the UK, it was slightly low at 236v AC, but thats acceptable.
Then ....
We have a garden full of water features and LED lighting.
I just decided to check all our power junction boxes that supply power to various pumps and lighting.
I found one of the boxes full of water, with the Live, Neutral and Earth, and the 12v DC cables all under water and shorted together.   The terminals were all corroded and burnt.
Yet, I had no faults present in the garden, everything was running normally.   And the RCD breaker had not tripped.
I repaired the box, fitted new terminals and rewired the box.
And since I did that, my Mac has cured itself.
I've had it running for hours to get hot, no noise, gone completely.
And the mains voltage now measures 242v AC (should be a nominal 240).
The RCD did not trip because, with all the cables shorted in water, there would no out of balance condition to initiate a trip.
So, I can only assume that arcing or the short was causing some harmonics on our mains supply that was been picked up by the coils in the Mac power supply.
The 12v DC supply in the junction box was also supplied by a switched mode supply.   I dont understand why something didnt blow in the garden, but it didnt.
I'm monitoring the Mac as the solution just seems unrelated.
Oh, and I noticed our Intruder Alarm panel was humming loudly and now it isn't.
So, I would suggest anyone with this issue takes note of any unusual humming or buzzing in any other electrical item within the house, or outside.   It may indicate you have an issue elsewhere.
Even any loose mains plugs in equiment could be causing a slight arcing on the contacts, causing noise on the mains that may be getting picked up.
Coming from an interest in high-end analogue Hi-Fi, amplifiers always performed better with a dedicated, clean, mains supply, usually from a 40 amp rated cable fed direct from your electricity meter to supply your Hi-Fi.
The amplifiers would exhibit less noise and a cleaner sound with more detail.   And the transformers in the power supply were a lot quieter too.
And what do we have today - ethernet tranducers plugged into household sockets, superimposing high frequency signals onto the household wiring.
They would cause havoc with top-end amplifiers, I'm sure.
I hope this is the solution, saves me an expensive repair.
I've never had any problems with the six Macs I've owned in the last 12 years.

Mac Pro 2010 and Lion: buzzing noise from CPU board when idle

Hi all,
I have a 2010 Mac Pro with the 3.2 GHz quad core. I recently installed Lion and now whenever the CPU load falls below a certain threshold (approx. 10-20%) something on the CPU board starts to make a buzzing noise. It sounds like a capacitor or coil. Sometimes it is nearly impossible to hear but most of the time it is quite annoying.
Removing the CPU board and putting it back in, solved it yesterday. But after waking up the system this morning, the buzz was back again.
Also, this does not happen when running Snow Leopard or Windows in Bootcamp.
Does anyone experience the same issue?
Best,
b.lam

Then I would do a clean Lion install. Hopefully you saved the installer DMG.
How to create an OS X Lion installation disc MacFixIt
Carbon Copy Cloner 3.4.1
Using Cloning as a Backup Strategy
Protocol Upgrading to Mac OS X Lion
RoaringApps Mac OS X Lion Application Compatibility
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This is the only problem I've ever had with my Mac and it is consistent. After running Google Earth for about 10-15 minutes the screen freezes and I have to force shutdown and reboot to rectify the problem.
I did some temperature measurements at the vent in the back and noticed a considerable temperature rise when running Google Earth. I think my graphics card is getting a serious workout and may go into thermal overload.
Has anyone else experienced this?

Hi dicoll
I can think of two thing that might cause the issue you describe:
_The first is how much ram is installed in your iMac?_
If your system is running low on available ram and paging out to the HD, when your running Google Earth it will cause the program to hesitate and or freeze. Try using the Activity Monitor, to monitor your ram usage and also to check for a failed process.
http://docs.info.apple.com/article.html?artnum=107918
_The second is what you describe as a thermal issue!_
To monitor temp's and fan speeds for a thermal issues there is the iStatPro widget. (Note the temp. for the GPU Diode)
http://www.apple.com/downloads/dashboard/status/istatpro.html
And then for monitoring and adjust the fan speeds there is smcFanControl Application.
http://www.macupdate.com/info.php/id/23049
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Noisy power supply when running of UPS? Is this normal?

Iv recently purchased a belkin 1500VA UPS, which in the near future i was looking to use on MAC Pro (once iv actually ordered and received it) The price was to good to miss, as it was currently on offer at misco and quite heavely reduced. So i went ahead thinking it would be a good idea to have for my G5 anyway. Everything setup a treat and the built OSX controls are fine but when the unit is on battery backup. Sleeping or in normal usage the actually G5's power supply makes a buzzing electrical sound from the power supply? I have read about this a little else-wear but no one has yet confirmed if this is normal/acceptable for a G5 to do this. Or the that the noise is the sign of a dodgy/faulty power supply.
I am aware the UPS also makes a noise when running in backup mode. But the UPS and the tower are some distance apart so i can quite easily identify that the noise is coming from the G5.
Any user experiences or advice on this would be much appreciate. I dont want to burn my power supply out. I still love my G5 very much. Cheers in advance for anyones assistance. Pob

Thankyou everyone for all of your responces. I think we're getting to the bottom of things now. It would appear that when in battery back up mode my UPS is generating a square wave which my powermac is not liking at all. And the power supply is working to put this right. Weather the work the power supply is doing and the noise generated is a sign of harm to my computer is still some what unclear. But it does not seem like a good noise as it is not normal.
It is also interesting that maclover has no problems using an APC smart ups that produces sine wave. So this points to square wave being the saurce of problems. Thankyou maclover for also pointing out that other very useful thread that concludes the smart ups range seems to be the way to go. Even tho a little more money i would prefer to have no noise! And be sure im not harming my Mac.
Malcolm Rayfield - I am under the impression my UPS does no produce a sine wave. And you saying that the noise is the input filter sorting it out does make sense. I am going to contact Belking and Apple tomorrow and hopefully either way confirm that this noise is a bad thing or just something iv got to live with.
DaddyPaycheck - My belkin model number is F6C1500EITW-RK. Quite a new model i think, dual form, 1500VA. Very pleased with all the features. This model does have AVR too (Automatic Voltage Regulation) But it would appear from what everyone has said along with some other findings about the web that this unit produces square wave! I guess yours is Sine wave hence you not having any problems.
I will probably end up returning this unit and buying an APC SUA1500i. As its been confirmed in this thread and the other thread that was linked to as producing a nice sine wave which is what i want. Again thank you everyone. Pob

24" iMac pauses when running

I have a 24" iMac 3.06 GHz Intel Core 2 Duo with 4 GB of RAM running Mac OS X 10.6.5 and when I'm running a movie in VLC player, music in iTunes, etc, it will pause for approx 2-10 seconds and then resume running.
Any thought of what it may be? Any hints on where to start looking for the problem? I've run everything in Disk Utility to check the disk thinking the hard drive was failing...
Help?

Hi Scott,
I'm interested to know where you managed to obtain ASD from - as it is not available to the general public...
Anyhow. The fact that your Mac is crashing when any OS is run indicates a hardware issue. My first sugestion would be to boot the mac into target disk mode, and check the panic logs located in /Library/logs. This may give you a starting point as to the hardware component causing the crash.
Secondly, I sugest swapping out the RAM modules and attempting to boot again. In many cases RAM can die suddenly and leave you in this sort of situation.
Failing that the machine will need to come apart for further isolation troubleshooting. If your a keen DIYer you can do this but I would highly recommend taking it to your nearest Apple store or AASP.
HTH

IMac Panic when running ASD

I have a late 2009 27" iMac. A couple of days ago it started locking up giving the grey screen with the "You must restart your computer" dialog in the center.
I had the correct ASD and when I run diagnostics in EFI mode the system shows absolutely no problems. I even ran a loop for 10 hours.
When I try ASD in OS mode I get a panic as it boots up. I am seeing the panic whenever an OS is run. My system runs Snow Leopard on the internal drive. A friend of mine runs Lion. I tried just booting up on a clone of his boot drive and I got a panic and now with the ASD in OS mode I get a panic.
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Thanks.

Hi Scott,
I'm interested to know where you managed to obtain ASD from - as it is not available to the general public...
Anyhow. The fact that your Mac is crashing when any OS is run indicates a hardware issue. My first sugestion would be to boot the mac into target disk mode, and check the panic logs located in /Library/logs. This may give you a starting point as to the hardware component causing the crash.
Secondly, I sugest swapping out the RAM modules and attempting to boot again. In many cases RAM can die suddenly and leave you in this sort of situation.
Failing that the machine will need to come apart for further isolation troubleshooting. If your a keen DIYer you can do this but I would highly recommend taking it to your nearest Apple store or AASP.
HTH

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When my Laptop (HP Pavilion g6 with Windows 8 (grrr)) is running there is always a loud noise of what I assume is the cooling system..... I dont know for sure. Every now and again it revs up and is a bit noisier. It is very irritating and I have wondered if there is anything that can be done about this. it only stops when I turn off the laptop. Any suggestions ? Can I get rid of it ? What might it be ?

Hi,
It could be a problem with your Fans if they are blocked up with dust this will make them less effective and could cause them to have to work a little bit harder. You could try using a can of compressed air to attempt to clear the fans of dust to do this see this Hp article. You may also want to try the other steps in the article to see if they work
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Re: GE72 2QF buzzing noise from CPU area when idle

Quote from: gilbert1019 on 14-July-15, 07:07:03You can disable "INTEL Speedstep" feature in BIOS and see if that would make the symptom disappear.
Sorry, I confused sides. It is actually coming from GPU area...

Quote from: mycenae on Yesterday at 03:11:26You could use MSI burnrecovery software to create a recovery media(USB or a few slices of disc) and reinstall your system. At that time, you can choose where to store recove...

New imac and a buzzing noise - is it normal because it's irritating?

Hello peeps,
I got my new imac delivered today. Most things are fab, but I'm a bit disappointed with a buzzing noise that only happens when I reduce the brightness of the screen using the slider in the display icon under system preferences. If I keep it at optimum brightness the buzzing doesn't happen. Is there any way of darkening the screen another way?
I'm finding it big and too bright initially as I'm not used to a 24" screen. Is this something that happens or should I send it back?
Anyone care to try theirs and see for me? I would really appreciate this as it's really bothering me and I don't want to complain if I don't have to.
imac Mac OS X (10.4.7)
imac Mac OS X (10.4.7)

Welcome to Discussions
Try using: Shades from Charcoal Design be sure to download the "Intel" version. Shades gives you brightness control all the way down to a black screen, great for working in a dimmly lit room.
http://www.charcoaldesign.co.uk/shades
It's only my opinion, but I find that text images stay sharper at the lower levels using Shades!
Dennis
17" iMac Intel Core Duo 1.5GB Ram Mac OS X (10.4.9) Maxtor 300GB FireWire Creative Inspire 2.1 2G Nano

The strap of my bag broke when my laptop was in it, now it is making a buzzing noise all the time and sometimes get a bit warm. I have warranty with protection plan, how do I fix it?

The strap of my bag broke when my laptop was in it, now it is making a buzzing noise all the time when I am using it. I have warranty with protection plan, how do I fix it?

Take it in and have it assessed. They do not have to know about the bag incident unless the explicitly ask for the specific details (like when you are being questioned by a TSA screener, LEO, etc.). As far as you know, the noise started up and it is getting warm. With luck it is just an unbalanced fan that needs replacement.

IMac 20" Core Duo - Buzzes When Running on APC BX900 Back-UPS

I pulled the plug on my APC BX900 UPS to test it, and all went fine (it showed 53 minutes remaining). I noticed though that during the 2 minutes I had the plug out of the wall (and the UPS battery was powering the iMac), I heard a buzzing coming from the iMac (sounded like it was from near the top left rear corner somewhere). As soon as I put the UPS plug back in the wall, and it switched to line power, the buzzing stopped. I suspect this may be due to the modified sine-wave that is produced when running from battery, and that the buzzing is associated with power supply components in the iMac. But, should I be concerned that during the (hopefully) few times this thing might kick into battery backup mode it's going to fry my iMac? I see very few confirmed reports of any such damage, and yes, I know a Smart-UPS (with sine wave output) would be preferrable, but if what I described is acceptable, and just purely a nuisance, I'll live with it. On the other hand, I don't want to melt this thing down trying to protect it. Thanks!
Mark

Thanks Eric. I'm not quite ready to assume the UPS is defective, although I agree it's a possibility. I have had other users in other forums report the same or similar buzzing, so I am inclined to believe my scenario is not unique. Then again, all of us "buzzers" may have defective UPS's.
I do have an APC BX1000 on another machine here at home (a Gateway PC), and I could swap them . . . what a maze of wires, etc, though. I'd prefer to avoid that too, but that might be my best course of action. Thanks again.
Mark

I have an iMac 2013 running OSX 10.9.4. I want to use Carbon Copy Cloner to backup user files to an external hard drive. Then I want to remove iPhoto libraries from iMac. What will happen to the iPhoto libraries that I back up when I run backup in a

I have an iMac 2013 running OSX 10.9.4. I want to use Carbon Copy Cloner to backup user files to an external hard drive to free up space on my iMack Hard drive.
So, say I make the backup today, delete iphoto libraries from my iMac, and then backup my iMac in a week. What happens to the iphoto libraries that are on the external backup drive now that I am backing up the iMac where they no longer exist?
I will have them backed up to a separate second external drive as well.
I'm just very cautious about removing them from the hard drive.
Thanks for helping and understanding my crazy caution!

I'd like to store my Aperture /IMovie Libraries on an external hard drive.
That is fine and recommended.. use the fastest disk you can afford.. ie Thunderbolt>USB3>FW800>USB2.
In addition, I'd like to partition the external hard drive so that Time Machine can use it to both back up my IMac and the external library drives.
Let me be clear.. you want to partition the one disk.. use it for TM and move your files to the external disk.. and then backup to the same disk.. You can do it.. but that is not a backup.. that is an experiment in how long you can get away with running files and backups on the same disk before you lose everything.. like Russian Roulette.. pull the trigger enough times and laws of probability will do you in.
You must have backups on a different disk .. otherwise it is pointless.
Can I set up a RAID 5 format for redundancy?
No.. you can buy special USB and Thunderbolt external drives that support RAID..
BUT that is still not a backup.. let me show why.. you make a silly move and corrupt your file in aperture.. it is not that rare.
Raid will corrupt all copies of the files.. it is replicated across all disks.
Delete a photo it is deleted across all disks.. you have no recovery.
Alway, always consider RAID system one disk.. backup onto another disk.. and if the photos or movies are at all important to you.. ie your family .. make another copy and store in a relatives house.. There is no such thing as too much redundancy.

Why does my iMac temperature go up when running games through Windows using BootCamp?

Hey guys,
These are my current specs: iMac 27 inch, intel i7 quad core 3.5 ghz, 16gb ram and 1tb sata hardrive with nvidia gtx 780m.
Ive installed windows on my mac and have discovered that when running games the temperature is much higher. For the same game on Windows i've had my CPU run at 80-81 C on roughly all cores and my GPU temp went up to 85 C. On mavericks same game runs at temps of 58 C for CPU and 71 C for GPU. However on mavericks the frames rates are lower even when running same settings as on windows.
I tend to think that mavericks is somehow limiting my hardware in order to keep the temperature down whereas on windows on my mac I can really feel the kick of the system yet the temperature goes really high. Is there any way to sort this out?

gpu driver optimising is much more used in windows it give better fps but less stability and as you notice more heat and more noise as the fans work harder
lower the eye candy and resolution is a cure

Buzzing noise in iMac(2013) when running on UPS.

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