MacBook Pro: Electrical "Hissing" sound

Question

Level 1

31 points

MacBook Pro: Electrical "Hissing" sound

My MacBook Pro is making a terrible hissing sound.
It's coming from under the keyboard, seems to be all over under the keyboard.
It sounds to me like it's a power regulator issue. The only was I can get it to stop is by using the Processor panel and turn off CPU2. As soon as I disable CPU2, the sound goes away. Turning CPU2 back on causes the hissing to return.

Is this a defective notebook, or is this "by design"?

Thank you

MacBook Pro 15" 2.0GHz, Mac OS X (10.4), 2GB Ram, 100GB 7200RPM HDD

Posted on Mar 2, 2006 9:10 PM

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Answer 1

Transeau Author

Level 1

31 points

Mar 9, 2006 11:07 AM in response to Transeau

Issue corrected.

After a nice letter to a few key people, Apple is aware of my issue and they are replacing my notebook. Though I do have to wait 2~3 weeks to get it, I don't mide waiting - I'm just happy that it will be replaced.

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Answer 2

Mar 13, 2006 5:56 PM in response to markm

My MacBook Pro seemed to be working fine (I have had it for about 2 weeks) but today I've been hearing the hissing/electronic noise. I read the posts between you and the person having the "hissing" problem. When you asked "Does the sound go away if you open PhotoBooth" I immediately opened PhotoBooth and the sound was gone. Why is this? As soon as I quit PhotoBooth, the sound came back on. Help. What do I do next?

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Answer 3

Transeau Author

Level 1

31 points

Mar 13, 2006 6:30 PM in response to sandionabeach

I'm no engineer, but I have a lot of experance with electionics...

My thoughts;
It seems to me that the noise is caused by an excess of power being generated to power a CPU that doesn't need it. The noise is the result of too much power being generated, and nowhere to go. When you open PhotoBooth, you are putting a load on the CPUs that cause them to start drawing more power. The Intel Pentium M (Core Duo et al) have an "enhanced" or "DeeperSleep" mode called "C1E" (C1 is the low power sleep state) While the CPUs are in the C1E mode, then are drawing almost no power.

Given that only some of the MBP's are having this issue, I feel that it may be caused by an open gound in the voltage regulation circut.

As I stated before, my replacement should be here April 8~10. The person that I was dealing with stated that they know about this issue - I hope the go public with it, and it's fix.

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Answer 4

Transeau Author

Level 1

31 points

Mar 13, 2006 9:33 PM in response to Bopchops

No need to be sorry!

To disable the second processor core, install the Developer Tools from the Mac OS X Installation DVD. Once installed, open the Preferance and open the Processor pane. You can select the option to show the control on the menu bar.

Then it's as simple as selecting 1 cpu or 2.

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Answer 5

Mar 15, 2006 5:52 PM in response to Transeau

Does anyone know if Apple came up with a patch for this problem. After waiting for a month for my MBP to arrive, I'd rather wait it out until Apple comes up with a solution rather than sending it back. Thanks in advance!

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Answer 6

Transeau Author

Level 1

31 points

Mar 15, 2006 8:07 PM in response to AppleAd4y

From what the Apple Exec that I am working with told me - Basicly, yes - they know of the problem and the current MBP's being shipped have corrected the problems.

I'll know for sure around April 10th.

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Answer 7

Mar 17, 2006 12:12 AM in response to Transeau

i got mine yesterday and it does have the noise.
How this people make a new computer, costing 2.500 dolars and dont try it!!!!
The noise is audible even in the apple store.
MacBook Pro 2.0 standard

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Answer 8

Mar 17, 2006 10:38 AM in response to dollystereo

The question is,

Has anyone actually received a replacement that that isn't hissing?

And another question...

Did you have to ship it back to them before they replaced it?

I have Apple Care Protection, should I just take it to an authorized vendor and get it replaced there?

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Answer 9

Transeau Author

Level 1

31 points

Mar 17, 2006 10:39 AM in response to Gilbeau

The reason that I sent a letter was that I paid $3000 for a new notebook, not a repaired notebook.

The Support Tech's response to my request was that I can send it in, and the will repair the defective speaker, but there is no problem with the hissing / whine sound. "That's a normal sound for the MacBook Pro."

I wasn't happy with that and I wanted it replaced.

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Answer 10

Mar 18, 2006 9:07 AM in response to raathempire

second question : yes, my MBP has been picked up two weeks ago.

First question : my replacement MBP is due to be delivered on March 28th.

Collateral reply : my MBP was exchanged because a hardware problem, not the whining issue. Though, the machine had the whine, the screen buzz, a left fan constantly on, and a strange "laser crossing" sound when I moved the screen back and forth around its latch axis.

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Answer 11

Mar 19, 2006 1:26 PM in response to raathempire

I have a stock configured 1.83 Macbook, and I am getting that electrical hiss out of the right speaker also. But, like others have said, it stops when I open a big program, like adobe lightroom, or, even weirder, when I scroll within a window using the touchpad, it will stop as long as im scrolling, once I stop, it comes back. Thing is 2 days old. I'm scared to put the gig of ram I have in.

And it is onl noticeable in a quiet room, but sit in a library cubicle with that noise for more than an hour, and you'll wonder why your have this horrible headache.

MacBook 1.83 Mac OS X (10.4.5) 300, 800 G3 ibook, G4 800 ibook, and G5 20" iMac, ipod video and 20g

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Answer 12

Transeau Author

Level 1

31 points

Mar 20, 2006 1:20 PM in response to Transeau

My replacement arrived today.

Audio quality (Defective Left Speaker?) is perfect now.

Hissing sound is still there, although the tone now changes when on A/C or on battery.

I think I'm going to sell it and wait for a major change in the product before buying another MacBook Pro.

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Answer 13

Mar 29, 2006 12:01 PM in response to Transeau

To disable the second processor core, install the
Developer Tools from the Mac OS X Installation DVD.

If you don't want to install the entire Developer Tools, you could just download the Apple Computer Hardware Understanding Development (CHUD) Tools at ftp://ftp.apple.com:21/developer/ToolChest/Testing_-_Debugging/Performance_tools/CHUD4.3.2.dmg

Once installed, go into System Preferences and you'll see a Processor Icon. For easy access, I clicked on Show Control In Menu Bar

Here's two snapshots of how it looks:
http://www.untenohana.com/archives/pictures/macbookpro/processordrop_down3-21-2006.jpg

http://www.untenohana.com/archives/pictures/macbookpro/onecore3-21-2006.jpg

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Answer 14

bayb735

Level 1

0 points

Apr 19, 2006 9:36 PM in response to Transeau

I'm having the same issue with my new MBP. I purchased it from the school bookstore and a week later exchanged it for a second one which has the same problem. I went to the Mac store to see if they could help me with the hissing. The guy at the genius bar told me that I received a MBP from one of the first shipments and the problem is in the first shipment of MBPs that came out. But, the hissing does go away when the camera is on. Either way...i'm still stuck with a hissing computer and have to deal with the bookstore since they sold it to me. Ask apple if they can send you a newer version. Hope this helps

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Answer 15

Apr 19, 2006 9:54 PM in response to Transeau

Pure speculation on the entire hissing issue, and I could be completely wrong, but 99% of the complaints about the hissing are from 'puters ordered direct from Apple. I purchased mine from an authorized reseller and have not experienced the issue...Not that it means anything, but as I stated; The majority of posts about hissing issues seem to have been ordered direct from Apple...

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MacBook Pro: Electrical "Hissing" sound