Powerbook hums when lowering brightness

I have a new Powerbook from Oct 2005.
When it lowers brightness due to powersaving or if I lower the brightness manually the Powerbook starts to hum. Not always but many times.
I've called the Support an send it to Apple. Now it is back and the problem remains.

Further details:
27' iMac mid-2010
3.2 GHz Intel Core i3
8 GB 1333 MHz DDR3
ATI Radeon HD 5670 512 MB
OS X 10.9.1 (13B42)

Similar Messages

T400 LED LCD (Samsung) buzzing when lowering brightness

Hi,
my LCD screen was recently replaced.
Just now, when lowering the display brightness, starting at 2 below max, my Samsung LED Screen omits a buzzing noise. It gets louder the more i lower the brightness. It is only really audible when i listen to it, so it is not that disturbing, however i would like to know if this is normal behavior?
I know from LCD TVs that some buzzing coming from the backlight inverter is normal, however, i am pretty sure my old LG screen was dead silent - even on lowest brightness.
Is my inverter going downhill or is it normal? Would appreciate other experiences. If someone would be so kind and check, put your ear to the left display hinge and lower brightness to 0.
Thanks.
Thinkpad T400 (Windows 7 Ultimate x64)

Guess i will have a service center to listen to it then. Since i do not use the lowest settings at all usually, it does not bother me that much. But if this indicates that the inverter may at one point break i might as well have this fixed.
Thinkpad T400 (Windows 7 Ultimate x64)

IMac screen blacks out when lowering brightness?

iMac 27" mid-2010
If I lower brightness, after a short while screen cuts out - computer works fine in background.
When I am on highest brightness - everything is fine...
Does anyone know what is happening here?

Further details:
27' iMac mid-2010
3.2 GHz Intel Core i3
8 GB 1333 MHz DDR3
ATI Radeon HD 5670 512 MB
OS X 10.9.1 (13B42)

27" screenbuzz when decrease brightness

27" screenbuzz when decrease brightness
This only happens when HD reaches +47 degrees celcius or +116 degrees Fahrenheit.
I first noticed this when I was transfering my picturs from my network drive to the iMacs HD. This where about 50Gb of data and just before the screensaver jumps in the screen brightness gets auto ajust to a less brighter setting. This is when I first noticed the noise or electrical buzz.
Please can anyone check if they are having the same issue. Because I'de realy like to know if this is a hardware problem or maybe just a software and fan setting/threshold related issue.
Kindregards NotoriousT

I returned my i5 tonight at the local Apple Store. 4 days old. They wanted to keep it for additional diagnostics for a couple of days, I wasn't up for that.
The Genius couldn't hear the noise since the store was so noisy; I could barely hear it sitting right next next to it and knowing what it sounded like.
I told him I'd accept a replacement if I could unbox it in a quiet area and listen to it to see if it had the whine. He said they didn't have the time to help me with that, and I told him I would not chance taking another whiney iMac home with me just to be back in a few days witht he same complaint.
Seems that for $2K you could get that type of cooperation. That was a disappointment.
So we agreed to disagree, and ultimately they agreed to a refund with no restocking fee. And I will be waiting and watching these boards for indications that the 1.0 bugs are worked out of them, then perhaps make another purchase at that time...
Interestingly, as I was wandering through the store to leave, I started chatting with a salesperson who offered to help me. I explained the day's events and mentioned the whine and he lowered the brightness on one of the C2D 27" iMacs on the floor and said, "You're right, this one whines, too."
My point exactly...

Powerbook freezes when I connect maxtor firewire drive

Ever since I installed tiger and upgraded to v 10.4.6 my G4 powerbook freezes when I connect a Maxtor firewire drive. I also recently installed Final Cut Pro Studio v 5.1. The maxtor drive mounts fine on another PB OS X 10.1.2. A Lacie firewire drive mounts fine on both computers. I can't figure it out. The powerbook with tiger crashes on startup when the maxtor firewire drive is attached or when it's just turned on. Does anyone have any solutions??

Welcome to the Apple discussion forums.
This isn't a guaranteed fix, however, did you update to 10.4.6 via software update or the combo installer? There have been some odd happenings recently when people have updated via the software update function. If you did the upgrade that way, you might try clearing your system and kernal caches (I use OnyX to do that, and other maintenance. It can be found at http://www.titanium.free.fr/pgs/english.html ). Then download the 140mb combo updater, which can be found at http://www.apple.com/support/downloads/macosx1046comboforppc.html .

Hum When Playing iTunes Through Airport Express

I have recently rewired my surround system, and now I am getting a hum when I play music through my Airport Express. I made no changes to the A/V receiver as it pertains to the Airport Express. I get no hum when watching the TV, only when listening to music though the Airport Express. Any suggestions?

Might it be possible that you may have some form of Wi-Fi interference in the area that may be the source of the hum that you're hearing from the AX?
I suggest you perform a simple site survey, using utilities like AirPort Client Monitor (a part of AirPort Management Tools), MacStumbler, or iStumbler to determine potential areas of interference...and either, eliminate them or attempt to significantly reduce them.

HT6154 Accidentally lowered brightness on my 5s can not see anything or make it brighter

Accidentally lowered brightness on my 5s can not see anything or make it brighter

Settings > Wallpaper & Brightness Adjust the brightness slider.

I am new to Logic Pro X. I am getting a 60 cycle hum, when trying to record humbucker equipped guitars.

I am using a new 27' IMac and an Avid fastrack 600 interface with Logic Pro X. I am getting a substantial amount of 60 cycle hum from both of my humbucker equipped guitars. I have experienced this with single coil p/us but never on HBs, at least to this extent. It varies in volume (the Hum) when rotating the guitar neck from side to side. Is there something unique about an IMac that could cause this?? Or maybe this interface?? Thanks.

I had that many years back, just made sure everything (Mac, Mixer, Guitar Pedal, Speakers) was coming through the same mains socket and completely shielded my guitar internals - Sorted it out straight away.
Changed pots in the process too, and my guitar (Tele Deluxe 72) saaaaaang after that!
My next step was to get a power conditioner with plenty of ac sockets, but never needed it in the end.
Does it stop if you put your hands on something metal? i.e. on the strings?

Low hum when converting analog to imovie

I'm trying to convert from Sony Handycam Hi8 analog to iMovie, using a Canopus ADVC-300. I get a low hum when I connect which gets worse when I press play. The hum is not on the original tape. Not sure what's causing this, but may be the cables? Here's what I'm using:
Out of Handycam: Svideo plus a mini-A/V output with red and white RCA at other end.
Out of convertor: firewire
I'd appreciate any advice. Thanks.

If the hum is not on the original tape, then it is probably caused by one of these issues. Check them out 1 by 1:
1 - a/v cable plug(s) not completely seated - check at the camera & at the ADVC
2 - camera audio out not set correctly (check the camcorder menus for the audio out setting ... usually you can toggle between headphone and a/v ... the wrong setting will generate hum ... you may need to try both settings)
3 - a/v cable is bad - try another cable
4 - ground loop ... three possible causes ...
• if you are running your ADVC and camcorder both on A/C power. Try running your camera just on battery, no A/C plugged in
• if you are running the ADVC on its power brick, disconnect the brick. The ADVC should still work via power from the FW cable - provided you are using the ADVC's 6-pin FW connector to connect it to your Mac
• both of the above
5 - some other audio device connected to your Mac at the same time as your ADVC
6 - ADVC is bad

Re: Qosmio X500-02G - Hum when I plug in into amp

Why does my Toshiba laptop hum when I plug into amp when using power adapter Qosmio X500-02G.
When I run on baterry no hum

Hi drs,
That means your notebook creates noises when AC/DC adapter is connected?!
Well, its hard to say something about this. Is the noise coming from your notebook or AC/DC adaptor itself?
What operating system you have installed?
Are you using newest BIOS version?
In your case I would check the current BIOS version and have a look on official Toshiba website for an update. After the update load the default settings in BIOS and check if this worked or not.

IPhone 3G Screen turns off when lowering from ear during call

I have my 3rd iPhone; bought it yesterday (last one stolen in Denver Airport). The screen works normally when using the functions other than the phone. When making a call everything is normal but when I put the phone to my ear, I have noticed that the screen does not turn off, however, when lowering the phone to look at the screen during the call, it goes completely blank despite the call still being connected. I tried pushing all the buttons to no avail. I did a reset and also a software restore without success. I discovered that when I lowered the phone during a call and the screen goes blank, I put my warm thumb over the little horizontal sensor above the screen and it would come back on. If I released my thumb it would turn off (the exact opposite of what should happen). I called apple, they said to return the phone because there probably is a hardware issue. I bought it at an ATT store in Santa Barbara, CA; I am told there is a restocking fee to replace the phone!! Amazing, buy a new product, its defective, return it for a new one, and they extract $20 additional dollars from you. Anyone else with a similar problem.

If it is not in a case and it is defective the only way that the AT&T store will swap out the phone for a new one without the restocking fee is if it's under 14 days. After the 14 days you have to bring it to an Apple store for repair or a replacement. I recommend purchasing the iCare warranty through apple, because it will extend the warranty to 2 years on the phone, and when your phone breaks the apple store will replace it on the spot if they can't repair it in the store instead of sending it out for repair and you waiting for it.

Why do I get a loud hum when adjusting the screen brightness?

I am getting an annoying Hum and the loudness depends on the how bright I have the screen, as I turn it down the hum becomes quieter. This is super distracting as I like to run my sound through external speakers, but the hum is just enhanced. I brough my unit it for service, they sent it out and said nothing was wrong with it.... Any ideas? None of my other computers make this hum!

Sounds like the inverter, which powers the screen is going bad. I'd bring it back.

Why does Powerbook freeze when attaching files?

I am working an a friends Powerbook G4 1.5 GHz 15", running Leopard 10.5.8.
Whenever I attempt to attach a file, located in applications, downloads, desktop, and when composing an email (any mail application, Yahoo!, etc), the Powerbook will begin with the spinning beach ball and will hang there. The only way to proceed is to power it off. Force quit doesn't work.
I have run diagnostics with DiskWarrior (succesfully rebuilt the directory), TechTool, and even performed an Archive and Install with the Leopard install DVD.
One possible clue. There was a Kernel Panic when I tried to start from the Disk Warrior DVD. I was only able to use it through Target Disk Mode from my iBook.
I also tried re-seating the Airport Extreme card and both RAM cards. System profiler looks good. All hardware is recognized and OK.
I may try to disconnect the DVD drive next but wondered if this problem might ring a bell for someone out there.
Thanks in advance!
Randy

Thanks for the reply. I'm sorry, my question wasn't clear. I was actually speakiing of web based email, like Yahoo.
Even though my friend said his hard drive is new, I decided to download a trial version of Smart Utility to his machine and had an Ah-Ha! moment. The drive is failing. I shouldn't ber so fooled when disk Utility and Disk Warrior say that the disk is OK. Directories and mechanics are two different animals.
Thanks for the permissions repair suggestion. I did try that.
The help is much appreciated!
Randy

Blank screen for few seconds when using "bright applications"

Hi
I have my MSI GF5600 VTDR256 for almost a year now and still facing the same problem (after various driver updates still existing :-( )
When I use application with a lot of bright colors, like Apple iTunes for example, the screen goes blank for 2 or 3 seconds and then returns to my application. Sometimes the screen isn't built up like it should be (pieces of text unreadable, desktop showing "through" some parts of the application). Problem also occurs when quickly scrolling websites with a lot of white in it.
I connected my Philips 170B4 17" TFT using a DVI cable to the MSI card. Don't know whether the problem occurs when using a VGA cable to connect my monitor.
The following screenshot illustrates how my screen looks after having another blank screen:
Somebody any suggestions?

I recently reinstalled my computer, so I started with the latest driver at that moment and the problem occured.
I have a 400 Watt dual fan power supply feeding:
- Gigabyte GA-7VRXP Mainboard
- 1024 MB PC2700 memory
- MSI FX5600 VTDR256
- 1 onboard RAID controller with two 20 GB Harddisk RAID 1
- 2 additional harddisks
- Sound Blaster Live Drive
- Plextor PX2410
- Plextor PX708A
- Floppy drive
- LeadTek TV Card (2000/Expert)

Buzz/hum when connected to krk studio monitors

ok so i have an imac (3.06 ghz intel core duo). i had a klipshe 2.1 speaker system connected with no problems. then i bought a pair of krk rokit 6's studio monitors and just have a whole lot of humming now. so far ive connected headphones to my imac and no hum.... connected my ipod to the krk's and no hum..... connected my krk's to my macbook pro (while it was plugged into the same outlet as my imac) and no hum..... bought a m-audio fast track and connected the krk's through that to my imac and still it hums.... what gives? please help. thanks
shawn

Shawn, I am getting a 1 KHz whine through Behringer Truth monitors using M-Audio USB Fast Track Ultra audio/midi interface with an iMac i5 27-inch with LED monitor. The whine occurs continuously from the moment I open Logic Studio or iTunes, when the output is routed through the Fast Track Ultra. The whine does not occur when I use the imac output to imac's speakers. I also get an electronic scraping noise when I use the blue tooth connected magic mouse. I have installed ferrites on the monitor speaker wires with no reduction in the whining noise or electronic scraping noise. I have also ordered the USB with ferrite collar to see if the connection between audio/midi interface and the imac is the source of the noise. I am considering a Hum-X, as well, but I am getting into serious money taking stabs at a problem for which there ought to be plenty of competent technical support. The fact that this whine is at 1 KHz and not lower suggests that I am not suffering a typical ground loop. I am a former Pro Tools user who never had a hum or whine from my Digi and G4, which I am seriously considering recomissioning so I can make music again. I am spending way too much time and money making educated guesses and trying to diagnose a problem that all but kills the utility and purpose of this new system. I too am calling on all great engineers to step up with a diagnosis and solution.

Powerbook hums when lowering brightness

Similar Messages

Maybe you are looking for