Anyone hear humming on screen dim?

[MaddMatt]

Hi All,

This has been at the back of my head for a long time, but seeing as I just upgraded to Jaunty, I noticed that the problem was still around:

When dimming the LCD on my MBP 4,1, a very high frequency hum can be heard coming from the screen area.

I know this is not normal, because if I boot back into OS X, and dim the screen, no sound is heard. Besides being annoying, I am afraid that the hum represents strain on the electronics. However, no hum is heard at full power, or full dim, but gradually increases in volume to 50% dim, before tapering off again towards the opposite extreme.

I haven't seen anything in the posts, so I want to know: does anyone hear this too? Is this my machine? I know for a fact that I didn't hear it in Hardy, though the software used for adjusting brightness has changed greatly (pommed, applesmc, etc.) in the last year or so.

Anyone have ideas or information about this?

Looking forward to some insight,
m

[MaddMatt]

Bump. I'd like to see more people vote in the poll to find out if this is just me or what.

[inphektion]

I have mbp5,2 and can dim down to before black. don't hear a peep out of it.

[MaddMatt]

Hmmm, well maybe this is just a Penryn problem (4,1). Can anyone else confirm this on Penryn?

[Salohcin]

I noticed this as well a while back, and am wondering if it has something to do with the pulsing of the led's.

Unfortunately i don't have my laptop in front of me, its in for warranty, but its a MBP 4,1, and i never really noticed the problem on previous installs with Hardy or Intrepid.

[MaddMatt]

Are you running 64 bit or 32 bit? That may be the difference, as I simultaneously upgraded from 32 to 64 and from Hardy to Intrepid, and it is when I was using 64 bit Intrepid that I first heard it. Let me know if you can still hear it when you get your laptop back from warranty, eh? Thanks!
m

[duk242]

Just thought I'd add, I'm a Mac OS X user, and my screen makes a feint hum when the backlight dims, it seems to be an issue regardless of OS (check google).

So don't blame Ubuntu for a Hardware issue :P

Ducky

[MaddMatt]

Hi Ducky,

I too run OS X on my Penryn Macbook Pro... And the screen dim hum occurs in Ubuntu but not in OS X- I am still searching for a solution but thanks for the input!

[linuxopjemac]

MacBook 2,1 has no problem like this.