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ShortcutToMoncton · Oct 20, 2007, 12:20 PM

Hello, I got a refurb 2.2Ghz Macbook Pro about a month ago, and it's been great so far. In the last couple days, however, I've suddenly noticed that the power adapter "brick" is making a buzzing sound. I wouldn't say it's really loud, but I can hear it when I'm about 2 feet away, and it I do notice it in class sometimes.

Is this normal? I don't remember noticing it before at all. The brick is quite warm to the touch as well. I don't want it to perhaps mess up my battery if it is acting up....

Thanks!

greg

mduell · Oct 20, 2007, 01:15 PM

Yes.

Cold Warrior · Oct 20, 2007, 01:17 PM

are you using it with the 3-prong cord or just the 2-prong adapter that connects into the brick? I never get buzzing from mine (MBP C2D 2.16), but I always use it with the 3-prong cord.

ShortcutToMoncton · Oct 20, 2007, 02:50 PM

I've noticed the buzzing using both – I use the 3-prong extension at home, and the 2-prong at school.

greg

ghporter · Oct 20, 2007, 05:05 PM

The little brick includes a switching power supply-which is why it can be so small and light compared to old-style, transformer-based AC adapters. It is not at all uncommon to be able to hear either the switching frequency or (more likely) a subharmonic of that frequency. It is perfectly normal. So is the box being a bit warm, for that matter; it's turning voltage on and off at a high rate, so it should indeed get warm from use.

If it gets HOT (too hot to touch-really hot, not just uncomfortably warm), emits any smells or smoke, or fails to power the computer, then you have a problem. If the buzzing is loud enough to be heard in a normal room environment, you may be able to convince Apple to replace it, but you'll probably get another refurb in exchange and then you're rolling dice as to whether you get a quiet one or not.

Cold Warrior · Oct 20, 2007, 05:22 PM

Indeed. Sometimes it's a crap shoot. I used to plug a 17-amp device into a 13-amp power strip, along with some other normal electronics, and there was about a 50% chance that the power strip would melt and nearly catch fire. Good thing I kept a stack of them in the corner, going through them until I found one that could handle the load.