Why is my new laptop buzzing? And why do dogs have wet noses?

January 26, 2007 6:23 AM

Why does my laptop make an annoying, high-pitched buzz when it accesses the hard drive?

New Dell 6400 laptop that I very much enjoy, with one exception. Seemingly whenever I do something that involves making the hard drive spin (load a web page; breathe) the computer issues a subtle, high-pitched hum.

It's seemingly an extension/augmentation of the usual hum the computer naturally emits. It just gets louder when it's working -- to the point of really annoying.

As far as I can tell the sound is louder when the screen is whiter. Like a blank Word doc. But here I may just be smoking crack. Using a scrollbar almost always seems to kick it up a notch.

It's not affected by the volume controls or wifi being on/off or the screen's overall brightness.

I borrowed a friend's MacBook Pro earlier this year and had similar issues (worse on the Mac). After nearly tossing the Mac into the trash compactor, I discovered that keeping the iSight application stopped the hum. Strange but awesome. Any such solutions/ideas for this?

Thanks!

posted by johndavi to computers & internet (6 comments total)

Just wanted to chime in that my Sony Vaio also does this at times (more randomly than your Dell though), and that I've also felt the pitch / sound changed depending on the brightness of the screen.

No solutions though. I stopped noticing it long ago.
posted by ClarissaWAM at 6:45 AM on January 26, 2007

Hard to diagnose from afar without a bit more info. First guess is that it's just the harddrive spinning. Maybe you could risk talking off the plastic fascia that covers the keyboard and listen to pinpoint where the sound is coming from?
posted by Burhanistan at 8:20 AM on January 26, 2007

The high-pitch sound you describe could be caused by a dead or dying capacitor somewhere in the system.

If that's the case, not much you can do other than get it repaired, hopefully under warranty.
posted by Merlyn at 11:11 AM on January 26, 2007

Call yourself some Dell tech support. I'll second Merlyn, whenever I see a hard drive making odd noises, I assume there's some sort of physical damage... and something in there's about to die.
posted by lilithim at 2:04 PM on January 26, 2007

On my Dell (Inspiron 8600) the whining sound is actually coming from the fan, and it increases as the load on the processor does. I just suffer through it. (I think the MacBook "mooing" problem was also fan noise, not drive noise)
posted by misterbrandt at 4:01 PM on January 27, 2007

It sounds to me (without having heard it) like it could be regulator whistle. There are a number of switching power supplies in the computer that control things like the CPU and the screen electronics. If poorly assembled, damaged or containing bad capacitors, these can whistle at audio frequencies.

As CPU load increases, so does the loudness of the whistle from the CPU regulator. Likewise for other regulators in the system, maybe for the LCD, definitely for the backlight.

Fans can increase in loudness as temperature goes up but that effect will lag behind the load by at least a few seconds, more likely a minute or more. If the effect is more pronounced on hot days and there is lag, it's likely to be a fan/thermal issue and therefore harmless.

Some (very cheap) motherboards in desktops tend to whistle under load too; one I had would chitter when there was heavy PCI traffic: disc, net, video, etc.
posted by polyglot at 6:36 PM on January 28, 2007