Imac 27 High pitch noise

[civictyper10]

I received my Imac 27 I7 and after the initial setup, I notice that the computer was making an high pitch noise coming from the left corner, when I change the screen brightness to minimum or to maximum the noise disappears, if the screen brightness is between 40 to 90% the noise starts again, as I´m an electronic engineer, I decided to disassemble the imac to search the cause and I found it. The problem is caused by the coils from the led backlight board, see picture and youtube video for better understanding, if someone on this forum works as an electronic engineer at apple, please check it and address this issue to the development team of the circuit.

You should push the volume up to listen the high frequency noise coming from the coils in the video.
http://www.youtube.com/watch?v=_8MWUH9ZhL0

[Btom]

I couldn't hear any noise (too high a frequency for YouTube?), but a buzzing converter points to a stability problem of the screen LED power supply - a shame really.
Also, it would be nice to have better resolution picture.

Tom B.

[CubeHacker]

I can hear the noise. You either need to turn the volume up or get better speakers ;)

And unfortunately, many type of LCD screens have this problem. Its nothing new and not only limited to the iMacs.

[civictyper10]

How can apple keep on selling products like this with a price tag of 2000 euros, that´s what I paid for and with such quality problems, I can´t understand, I have a macbook pro, a ipod classic and a ipod shuffle no problems whatsoever, and those products were way cheaper than the Imac.

[Btom]

Nope, nothing here. Some static-like white noise, board handling noises, but no high pitch noise on my side (my computer is past its' prime, though). I can hear a buzzing noise on this (http://www.youtube.com/watch?v=jXyH1XGFFck&NR=1)YouTube piece though.

Tom B.

[civictyper10]

you should listen carefully, it´s not a buzz, it´s like a dog whistle


Nope, nothing here. Some static-like white noise, board handling noises, but no high pitch noise on my side (my computer is past its' prime, though). I can hear a buzzing noise on this (http://www.youtube.com/watch?v=jXyH1XGFFck&NR=1)YouTube piece though.

Tom B.

[Btom]

you should listen carefully, it´s not a buzz, it´s like a dog whistle

My computer is ~10 years old, but I know what mean.

Tom B.

[enginyr]

I have the same dog whistle type sound that I can only hear while 5 feet away in bed.

[Sargiel]

I have a white 24" C2D iMac (just over 3 years old now) and I have the same thing. If I have the brightness on anything but max then the noise is noticeable/increases.

[adammjenkins]

I am on my 3rd iMac with this same problem, only mine have been accompanied with a sporadic buzzing noise which is also associated with the screen brightness, which is more prominent if the computer is running a little hotter. I recently attempted to get a refund altogether just because I am tired of the headache and lugging this monster around, but get this: after 3 faulty machines (as diagnosed by an Apple Care senior advisor), the engineering department placed a necessity on this computer to be physically inspected by an Apple-certified technician. The closest Apple Retail Store is almost 2 hours from my home. So if I take it, come back home, and then have to make an entire other round trip to pick the thing back up, that's 8 hours of driving, gas, wear and tear on my car, plus managing to get the time off work to take this thing in AT MY EXPENSE. Somehow, this doesn't seem right.

I must say, though, I've had a great experience with Apple's phone tech support through Apple Care. However, once the case was handed over to Customer Relations, my entire experience turned sour. All the while through the technical support, I kept being told that "there should be no noises associated with adjusting the screen brightness." My ultimatum is to either a. make the drive as described above, b. Fex Ex it to them (AT MY EXPENSE), or c. live with the noise, worry about long-term failure, and sell the thing once Apple Care is up. I am so completely disgusted with this multiple-month long situation that I am opting for the latter choice.

I wish anyone else trying to get their machine that have this issue repaired/replaced the best of luck. I certainly haven't had it. :mad:

[josebly]

Hi, i have simmilar problem on the imac 27 i7, but maybe lower frequency and all the time, independly of brigness.
noise seems to come from left lower corner.
attached you have a audio recording done with the imac internal microphone (just seeting a coin or simmilar on top of the microphone to amplify the noise on the computer case) and a plot of the audio spectrum. the freq of the noise is at 123Hz.

jl

I received my Imac 27 I7 and after the initial setup, I notice that the computer was making an high pitch noise coming from the left corner, when I change the screen brightness to minimum or to maximum the noise disappears, if the screen brightness is between 40 to 90% the noise starts again, as I´m an electronic engineer, I decided to disassemble the imac to search the cause and I found it. The problem is caused by the coils from the led backlight board, see picture and youtube video for better understanding, if someone on this forum works as an electronic engineer at apple, please check it and address this issue to the development team of the circuit.

You should push the volume up to listen the high frequency noise coming from the coils in the video.
http://www.youtube.com/watch?v=_8MWUH9ZhL0

[tonysan]

Hi to all!
I am new here, so hello to everybody!!
Well, I can totally hear the sound described above. It just hits my nerves.
My story about iMac 27'' goes like this:
I bought one a few weeks ago. But sometimes it turned on (you had to roll the dice or play lottery whether it was going to turn on or not - basically the screen didn't turn on, not the machine itself). It turned out to be a backlit (don't know if the spelling is right, but anyway..) problem +it had somekind of dead pixel, which could be seen even when the computer was turned off (!) - it looked like some sort of crystal thingy - misconstruction of the screen(??) don't reall know...(any ideas from you are totally welcome!) :)
Anyways, the seller (by the way I live in Greece) was kind enough to give me a new iMac. So I waited for 2 weeks and the new machine arrived, but...has these issues: 1. It makes a buzz noise from the upper left corner of the back of the machine when the brightness falls to minimum, 2. I CAN hear this high pitch noise when the brightness is between 30-90% or something (I want to puke in 15 minutes because of it, really), 3. 4 dead pixels (black) and the crystal thingy is back in te center and a bit downwards of the screen. And the most unlike event: I took it to the store (which is the also the official service center) the buzz noise stopped (what the hell..?), they couldn't hear the high pitch sound, and for the pixels I asked them how many is needed to get a replaement (and they didn't know!!).
The conclusion: I am the Anti-Christ(!) or a werewolf(!) or something and I can hear sounds with high frequency... :))
No serisoulsy, would it be my fault if I smash the computer or not??
Please, any suggestions?? One thing is for sure: I won't ever, ever going to buy a product by Apple - the most irresponsible company in our days.

Thanks for reading, hope to get some advice from you...
Looking forward,

Yours Antony

[civictyper10]

Hi Tony,

Sorry for the late reply, If you go to the store with the computer, it´s very difficult to hear the noise because there is so much sound frequencies around your ears, therefore you and the technician have to listen to it, in a quite room, to completely trace the noise coming from the iMac, otherwise the technician would think that you are crazy and won´t believe you.

I made some tests and I can say with 100% confidence that:

Buzz noise = to power supply
High frequency noise = Led backlight board

Best regards.

Hi to all!
I am new here, so hello to everybody!!
Well, I can totally hear the sound described above. It just hits my nerves.
My story about iMac 27'' goes like this:
I bought one a few weeks ago. But sometimes it turned on (you had to roll the dice or play lottery whether it was going to turn on or not - basically the screen didn't turn on, not the machine itself). It turned out to be a backlit (don't know if the spelling is right, but anyway..) problem +it had somekind of dead pixel, which could be seen even when the computer was turned off (!) - it looked like some sort of crystal thingy - misconstruction of the screen(??) don't reall know...(any ideas from you are totally welcome!) :)
Anyways, the seller (by the way I live in Greece) was kind enough to give me a new iMac. So I waited for 2 weeks and the new machine arrived, but...has these issues: 1. It makes a buzz noise from the upper left corner of the back of the machine when the brightness falls to minimum, 2. I CAN hear this high pitch noise when the brightness is between 30-90% or something (I want to puke in 15 minutes because of it, really), 3. 4 dead pixels (black) and the crystal thingy is back in te center and a bit downwards of the screen. And the most unlike event: I took it to the store (which is the also the official service center) the buzz noise stopped (what the hell..?), they couldn't hear the high pitch sound, and for the pixels I asked them how many is needed to get a replaement (and they didn't know!!).
The conclusion: I am the Anti-Christ(!) or a werewolf(!) or something and I can hear sounds with high frequency... :))
No serisoulsy, would it be my fault if I smash the computer or not??
Please, any suggestions?? One thing is for sure: I won't ever, ever going to buy a product by Apple - the most irresponsible company in our days.

Thanks for reading, hope to get some advice from you...
Looking forward,

Yours Antony

[tonysan]

Hi Tony,

Sorry for the late reply, If you go to the store with the computer, it´s very difficult to hear the noise because there is so much sound frequencies around your ears, therefore you and the technician have to listen to it, in a quite room, to completely trace the noise coming from the iMac, otherwise the technician would think that you are crazy and won´t believe you.

I made some tests and I can say with 100% confidence that:

Buzz noise = to power supply
High frequency noise = Led backlight board

Best regards.

Hi again!!
Thanks a lot for your reply. I appreciate it more than you can imagine.
The funny thing is this:
The technician told me that he fixed - changed both the power supply chip(?) (from inside) and the backlight supply, and guess what: 1. the buzz noise remains exactly the same, 2. the high pitch noise remains the same. It is as if he didn't repair anything..
Any ideas? For example is he lying?? Or the machine is so ********* up (trully sorry for the language, but the whole situation is really annoying) that I need to return my money or give me a replacement?
Thank you for once more,

Yours

Antony

P.S. Here are 2 videos that I recorded with the buzzing noise:

http://rapidshare.com/files/398851435/iMAcBuzzNoise.rar.html

Feel free to check it out

Thank you again

[WardC]

I just got a 27" i7 iMac today and mine is exhibiting this issue. The machine is running VERY hot, and it's emitting a very high frequency squeal sound (like an electronic squeal but loud). When I turn the screen brightness to 50% then the sound goes away. It is the loudest when the screen brightness is between 80% - 90%. I can still hear the noise at full brightness but it's not as loud, still unbearable...but with the screen that bright I get a severe headache. I can't run the machine at anything but 50% to 60% brightness or this loud squeal is too annoying to deal with. I think maybe this has to do with the LCD overheating or something, I mean the machine is really, really hot.

[Btom]

I just got a 27" i7 iMac today and mine is exhibiting this issue. The machine is running VERY hot, and it's emitting a very high frequency squeal sound (like an electronic squeal but loud). When I turn the screen brightness to 50% then the sound goes away. It is the loudest when the screen brightness is between 80% - 90%. I can still hear the noise at full brightness but it's not as loud, still unbearable...but with the screen that bright I get a severe headache. I can't run the machine at anything but 50% to 60% brightness or this loud squeal is too annoying to deal with. I think maybe this has to do with the LCD overheating or something, I mean the machine is really, really hot.

Back to the shop, get refund, buy yourself another one a few days later...

Tom B.

[Michaelgtrusa]

Is Apple headed for legal trouble?

[WardC]

Back to the shop, get refund, buy yourself another one a few days later...

Tom B.

I am taking it back to the Apple Store tomorrow. I just hope they will give me a full refund and not charge me a $219.90 restocking fee (my receipt says that I will have this exact restocking fee on returns).

Does anybody know Apple's policy on this? If I can prove that it's defective can I get a full refund? I've now decided I don't want to put up with this and I'd rather not exchange for another iMac, I've decided I'd rather keep my old monitor and probably get a Mac Pro. So will I have to pay the steep restocking fee on return?

[dwarnecke11]

I am taking it back to the Apple Store tomorrow. I just hope they will give me a full refund and not charge me a $219.90 restocking fee (my receipt says that I will have this exact restocking fee on returns).

Does anybody know Apple's policy on this? If I can prove that it's defective can I get a full refund? I've now decided I don't want to put up with this and I'd rather not exchange for another iMac, I've decided I'd rather keep my old monitor and probably get a Mac Pro. So will I have to pay the steep restocking fee on return?

I took my flickering yellow i5 back within 10 days and I got every cent back. IIRC, if it is defective, they won't charge a restocking fee.

[toolbox]

I ordered mine better not have these problems, its a CTO unit.

[Btom]

I am taking it back to the Apple Store tomorrow. I just hope they will give me a full refund and not charge me a $219.90 restocking fee (my receipt says that I will have this exact restocking fee on returns).

Does anybody know Apple's policy on this? If I can prove that it's defective can I get a full refund? I've now decided I don't want to put up with this and I'd rather not exchange for another iMac, I've decided I'd rather keep my old monitor and probably get a Mac Pro. So will I have to pay the steep restocking fee on return?

If they charge restocking fee on a FAULTY unit, I'd call it a new (crooked) business model and call Apple directly.

Tom B.

[dexthageek]

I have had my 27'' i7 for just over a week, no buzzing sound (thank god) and mine is a refurb :)

[WardC]

I took the 27" iMac back to the Apple Store this morning. They gave me a full refund ($2,340.40 - including tax)...I opted for the Apple Gift Card refund which I am going to use on the purchase of a Mac Pro from the Apple Store website. At least they gave me a full refund!! I don't have to put up with this noisy machine anymore. It was the "dog whistle" sound, very loud extremely high pitched whine coming from the LED screen.

[dirkvidor]

I pulled out the plug at the rear once shut down, apparently this resets the fan and power setting or something. Any way this worked for me!

No more high pitch noise, I think mine was associated with the fans.

Regards

[amiralmuminin]

Has anyone had any success getting a technician to acknowledge this or any other sound-related backlight issue? I'm on my 3rd iMac. The first had the buzz when the display was dimmed, so I swapped it for one with the same problem. I packed that one up and exchanged it for a 3rd machine with this dog whistle that is infinitely more annoying than the buzz.

The "geniuses" at the Apple store have not been very helpful. They insisted they've never heard of this problem, and refused to offer me another replacement. After taking notes that were suspiciously different than the problem I described, the "genius" checked the computer in overnight to try and recreate the sound. Sure enough, three of their "geniuses" couldn't duplicate the sound in 24 hours...I was able to do so 15 minutes after bringing the machine back home.

The last technician I spoke to kept trying to tell me that since I've been through three machines, that the problem was environmental, or the sound was normal and I just had really acute hearing. I then had to explain for maybe the fourth or fifth time that the other two did not whistle like this, and if I would have known I'd be stuck with this whistling computer, I would have never brought the first one back. I don't think I should have to be longing for a less-annoying, yet still defective computer just to avoid this customer-service-hell they've put me through. And if it's just the natural hiss of the bulbs I'm hearing, why don't I hear them at 100% brightness...genius!? Finally, the technician said that all he could do at this point was refund my money...which I would gladly accept, only I'd be out $300 in rebates.

If anyone got one of these inept, converse-wearing hipsters to hear the whistle...please, let me know how you did so. Your help would be greatly appreciated.

[Iamthinking]

I am on my 3rd iMac with this same problem, only mine have been accompanied with a sporadic buzzing noise which is also associated with the screen brightness, which is more prominent if the computer is running a little hotter. I recently attempted to get a refund altogether just because I am tired of the headache and lugging this monster around, but get this: after 3 faulty machines (as diagnosed by an Apple Care senior advisor), the engineering department placed a necessity on this computer to be physically inspected by an Apple-certified technician. The closest Apple Retail Store is almost 2 hours from my home. So if I take it, come back home, and then have to make an entire other round trip to pick the thing back up, that's 8 hours of driving, gas, wear and tear on my car, plus managing to get the time off work to take this thing in AT MY EXPENSE. Somehow, this doesn't seem right.

I must say, though, I've had a great experience with Apple's phone tech support through Apple Care. However, once the case was handed over to Customer Relations, my entire experience turned sour. All the while through the technical support, I kept being told that "there should be no noises associated with adjusting the screen brightness." My ultimatum is to either a. make the drive as described above, b. Fex Ex it to them (AT MY EXPENSE), or c. live with the noise, worry about long-term failure, and sell the thing once Apple Care is up. I am so completely disgusted with this multiple-month long situation that I am opting for the latter choice.

I wish anyone else trying to get their machine that have this issue repaired/replaced the best of luck. I certainly haven't had it. :mad:

Hey Adam I share your pain. Had pretty much the same experience, except that I didn't have to go quite as far for the "Certified Apple Tech" to check it (We have a couple of these guys on campus where I work- they sometimes call me for advise on some problems that stump them <g>)

-Most of my problems on the replacement notsomerry-go-round related to the crappy displays on the 21.5" model. It wasn't until I gave up on the 21.5" and upgraded to the 27" that I got to experience the dog whistle "feature".

But man, that customer relations dept. - what a joke. I had a lady screaming and swearing at me (and calling me a liar, I might add) as I was trying my best to calm her down. WTF?

I have the whistle "noted on my file", and when I have another 2 months to waste trying to get a decent iMAC (probably next summer) they hopefully will have a record of the fact I noticed the issue right away. Guess I'll used the old "car with squeaky brakes" fix for now - crank up the radio and try to ignore the high pitch dog whistle - at least the screen is much better ! :-)


-Iamthinking

[candy.man]

I have a (new) 21.5" iMac with high frequency noise problem. I called Apple support and they said its due to static buildup. He advised me to do a couple resets and it worked. No more annoying dog whistle. thank god!

First, a hard reset where I shut down the computer and unplugged everything from back: power cord, ethernet cable, etc. Wait a minute, then plug it back in and turn on.

Second, reset the parameter RAM. This one is tricky. Shut down iMac. When power is off, press and hold Command, Option, P and R keys at same time. Then hit power button. Hold all four keys until you hear the second startup sound. Detailed instructions posted here:

http://support.apple.com/kb/ht1379

Good luck

[candy.man]

Now I just need to remove the sound from my head..

[amiralmuminin]

I finally got a "genius" to hear the whistle; he offered a replacement and I agreed. You'd think after 3 crappy machines, I would have learned my lesson. The one I'm on now has a dog whistle more pronounced than the last and a bunch of other issues as well. The machine makes a ticking sound when powered off (that's right, OFF), the bluetooth file transfer is incredibly slow (not sure if this is a hardware problem), the machine refuses to go to sleep automatically (this either), and, perhaps worst of all, it's got the ugly yellow tinge--most apparent in the bottom left hand corner.

I packed the bad boy up and took it all the way back to the retail store, thinking that the problems would be easy enough to demonstrate. I spoke to two geniuses, mostly about the tinge (while the other stuff is annoying, I edit photo/video professionally...I wanted them to just fix the tinge on this machine so that I could move on with my work and my life). The first "genius" told me that the newer models had a firmware update that solved the tinge problem (turns out this is not true). I tried to demonstrate the problem, and it wasn't working out--the "genius" couldn't see the subtle variation. He called another technician out to take a look and what followed was the most ridiculous corporate display I've witnessed in all my years as a consumer. I pulled up gray-barred test pages that clearly illustrated the nasty tinge across the bottom half, and watched two adult men pretend that they didn't see what I was talking about. I got one of them to concede that there could be a slight variation, but he claimed that it disappeared when he was looking at the screen perpendicularly (which is funny, because the only time I notice the tinge is when I look at the screen perpendicularly).

The genius told me that the machine would pass all their spec tests, and that he couldn't exchange or return it without charging me a restocking fee. He said if I did decide to exchange it, it would be a gamble, and that the new machine could have problems that I considered even worse (yeah tell me about it). Then he told me that I should feel lucky that I don't have any dead pixels or other anomalies. WTF?

I didn't even bother mentioning the other problems. I took my machine and left. The return date has come and gone and I think I'm stuck with this machine...my 3rd replacement and by far the worst iMac I've brought home in this horrible horrible experience.

Don't buy this model and, if you can avoid it, don't buy Apple products.

[PellePirat]

I to is VERY dissapointed about this issue.

I just got an iMac 27" with the high pitch whine.

It got repaired, the LED board got changed, and i got i back with the same whine :-S

Im returning the machine for a refund, which is very sad, since i really like the machine. I guess i must settle with my 3 year old 24" with almost no bleeding on the screen....sigh...

Just a question for OP. You guys reckon that

http://www.kaisertech.co.uk/acatalog/Products__Servisol_Plastic_Seal_60_65_Conformal_Coating_476.html

could solve the issue? You often spray PSUs with plastic coat to eliminate high pitch vibrating.

It could be worth a shot?

I was hoping OP could answer this with his electronic background.

Thanks a bunch

[urartu]

hi civictyper10, have you (or anybody else in this forum), succeeded eliminating the dog whistle sound by changing the led backlight board?

there are different reports out there - some with success, such as this one:

http://gullycat.wordpress.com/2011/01/13/buzzing-high-pitched-noise-2010-imac-27/

some without success, like tonysan here:

http://forums.macrumors.com/showpost.php?p=10133479&postcount=14

any comment is welcome!

thanks!

[littlebunnynose]

Saw this thread when my iMac started having problems. Now that it's been fixed (again), I thought I'd share my experiences. Kinda long but please bear with me.

In mid-December 2011, the Seagate 1TB HD failed in my late 2009 27" 2.8 GHz Intel Core i7 iMac. Besides a bad HD, the Apple store technician tested and diagnosed other problems; namely, a bad power supply unit and bad internal cords. The parts were replaced ([sigh] yes, another Seagate 1TB HD was installed) and, just before 2012 began, I got the iMac back home. As soon as it powered on, a buzzing sounded from the left back side. Whenever the monitor's brightness was increased, the buzzing noise increased in volume. At maximum brightness, the noise was louder than the nearby stereo radio set at speaking voice volume. I forget where I read (maybe on the Apple support forum?) the suggestion to remove the power supply cord and then re-plug it in, which for one guy helped resolve his buzzing noise. So I tried it and much to my horror and disgust, the iMac would not power on. This failure to power on happened only a few hours after the repaired iMac was home. Finally after about an hour of trying, the iMac powered on. But then over the next few days the buzzing noise worsened.

Since in initially coming to the Genius Bar and then picking up my iMac I had met with bad experiences ((1) the "genius" who confirmed that the HD was failing and suggested I take the iMac home to try to salvage my data also managed, in repacking the iMac in its box, to leave the power cord behind the Genius Bar counter (and of course none of the geniuses called my cell phone to inform me that they had it), which necessitated another round-trip to the Apple store; (2) the store threw away my iMac box, with Styrofoam inserts; and then (3) the store manager insisted I never brought in the iMac with its box because, he said, it was store policy that OEM boxes were not accepted with Apple products brought in for repairs. (The "genius" who did the intake told me to leave the mouse, keyboard and power supply cord at home when I next dropped off the iMac; he never said anything about leaving the box home too.) If the manager (and I recognized him as formerly being a store "genius") had had the sense to apologize instead of telling me that "we will be civil" and then to imply I was a liar in insisting I brought my iMac in its box, I would not be writing this screed. Worse, he compounded his bad customer service by threatening to ban me from the store when I suggested in passing to a woman, waiting with her boxed 27" iMac by the store entrance, that she not bring her iMac in its box for repairs because the box will be thrown out like mine was), I decided to go to a non-Apple store authorized repair shop. Surprisingly this shop was closer to my home than the Apple store (found its information on the Apple website). The second repair shop technician diagnosed not only a bad power supply unit (remember, the bad one had just been installed by an Apple store tech), he also determined that the buzzing was coming from a defective LED backlight board. Those parts were replaced and now my iMac is once again back home, safe and quiet.

Oh, and in removing the display glass from the iMac's monitor, the Apple store tech left dirt specks under the glass. So of course in processing my RAW and JPEG files, I found myself trying to remove those specks until I realized that a Photoshop brush was not going to make them go away. Anyway and much to my delight, the second repair shop made sure to wipe the brown specks from the glass.

Truly it is wonderful to find a non-Apple store authorized repair shop that not only listens to its customers and treats them with respect, but also does good and prompt repair work. Thank you, macVolks of Concord, California.

[pionata]

My iMac started to make that unbearable hi-pitch whine sound as well (had it for 1 year).

There is no way to work with this, extremely disappointing.

Days will be wasted again to get this fix, that is if I don't fall on a bunch of incompetents.