21.5'' iMac - Screen Noise

Everyones ears are different. For me, raising the brightness increased the frequency, but it is still audible. It just is not as annoying at that frequency.

My 21.5-inch iMac seems to be from week 45, and it whistles. It's a VERY quiet whistle though. It's the kind of very high frequency noise that Plasma TVs make. Maybe it's normal?

I am near Dallas when I bought my 21.5" iMac, not sure what week my iMac was made, but it has the same symptoms. Top 2 brightness levels, sound is gone/weak. Go down near half and sound gets louder and extremely annoying. I noticed this the second day. If there is no firmware fix soon, I'm taking it back.

I called Apple support. They said to reboot with the DvD in drive, problem still persists. Sound goes completely away on one of the first 6 brightness notches, moving higher from there it starts up and gets worse except a little quieter at the 2 brightest notches.

The person on the phone said this is the first that she has heard of this. I am using the upgraded 21.5 iMac, the one with the ATI Radeon HD 4670 graphics card. Are other people having the same issue with the 9400M video card? Please respond if you are.

I am also thinking this might be some kind of burn in process, as a few hours ago for the first 5 brightness notches I heard nothing at all, and now it is the first 6 notches.

I called apple support several days ago- told the tech that I had an order for a 21.5 iMac in my saved apple store cart and was waiting to place the order because of all the posts in this thread about the LCD noise. At first he said that he was unaware of the problem, but then checked his "knowledge database" After a few minutes he said that apple has issued a "capture" on all new iMacs with this problem, meaning they want to send all returned products somewhere to be stripped down and examined. I told him that at this pont I will hold my order until I get the "all clear" from either apple (with an official announcement that the problem that they refuse to publically acknowledge has been fixed) or people on this forum who are satisfied with the product.

Zeta9
I had the 9400M video card and was having the same problem. I got a new one with the upgraded 4670 video card and had the same issue. I am waiting on a third replacement. Hopefully this will be the one. I hear the noise at lower brightness levels and not so much at the highest setting.

Sorry to hear that Jeremy. I have also tried changing the screen resolution, and plugging the power cord directly into the wall, and there is no change. If I don't hear back from apple soon I will have to return it to best buy.

If your new iMac was bought online from the Apple Store and customised, what's the procedure for exchanging it?

Will Apple send you out a replacement unit and will they collect your defective (whistling) one?

Alternatively, perhaps you can drive your defective (whistling) iMac to a physical Apple store, and leave it with them. Then use the Apple Store online to get a replacement unit ordered and delivered straight to your home?

I took my 21.5" back to best buy. Tested the one on the floor, and had the geeksquad unbox a new in their install room where it was quite. Same exact thing on both of them. Drove to apple store. Just finished setting it up. Same exact thing, with different serial number sequence, and this one has a dead pixel straight in center of the screen as well. There are 16 notches for brightness from 0-5, no noise. 15-16, little noise. 6-14, annoying noise. Of course, this is where most people are going to set their brightness level to, somewhere between 6-14.

Thought I was going crazy, asked my wife to check. She heard the noise easily. Anyone who has good ears/eyes had better think twice or 3 times before buying a 21.5".

Is there anyone reporting noise from a 27" model?

Same issues on 27inch model. Have the 3rd one at home.

Best regards,
Steve

Steve, your other 2 - 27" models, did they have the brightness noise too or just the other issue?

And it appears my dead pixel was just a lazy pixel. Time will tell.

Actually at the beginning I wasn't aware that both issues were really different. But now as I had them both I can say the following:
1st and 2nd model: Screenbuzz when brightness decreases issue. I didn't notice the high pitch noise issue I have now on the upper brightness levels.
http://discussions.apple.com/thread.jspa?threadID=2219880&tstart=0
After long calls with Apple and my reseller I got a 3rd model without the screenbuzz issue. My reseller had trouble finding a new one as almost all the iMacs they got had the screenbuzz issue.

3rd model:
Now I have the really disturbing high pitch noise issue described in this topic. I can hear it really well between 50%-90% brightness level. I will give my reseller a call this monday to see what we can arrange.

Steve

steve_lux wrote:
Apple told me they are working on a firmware update now.

Is that true? Did they really tell you that? If this problem can simply be fixed via a firmware/software update I'll be very happy.

My iMac hardware seems perfect. It's just that **** whistling noise. It's such a small imperfection, yet such a huge annoyance. I really hope software can magically make it disappear.

Sounds confusing now, but at the beginning I thought this thread and http://discussions.apple.com/thread.jspa?threadID=2219880&tstart=0 were related. As I experienced both issues now, I can tell they manifest in different ways.
Both problems generate some screen noise, a high pitch noise vs a buzzing electric sound. The first issue arises at upper brightness levels (expect at 100% for me) and the second problem occured at lower brightness levels.
Apple told me that they were working on an update for the screenbuzz issue: http://discussions.apple.com/thread.jspa?threadID=2219880&tstart=0. But on the other hand I don't know if the technician really understood the difference between both problems. My reseller told me they were awaiting some parts to fix the issue. Why would they order parts if Apple would release a firmware update? Honestly I don't know... Therefore I would not consider the firmware update too seriously until Apple releases a more official statement.

Glad I found this out, was just about to order the 27 inch. Looks like I'll keep my old imac a while longer. Common Apple, are you doing any quality control on these machines. At the cost your charging this is downright unprofessional!