View Full Version : iMac G5 17": Should be sleeping but fans are loud

Blue Velvet
Jan 14, 2005, 09:11 AM
Am posting this on behalf of a colleague.

His new iMac 17" superdrive OS 10.3.5 is giving him some grief upon putting it to sleep...

During working hours the iMac is apparently quiet, but when it's put to sleep apparently the fans whir up to full speed and don't stop unless the machine's plug is pulled from the mains socket.

I vaguely remember a few people mentioning something like this, but no searches on this forum have revealed anything specific.

Any clues, tips or links?

p.s. Have just downloaded and given him the 10.3.7 updater, if that's any help...

Blue Velvet
Jan 14, 2005, 10:46 AM

Jan 14, 2005, 11:55 AM
hmm, I don't know...

maybe the usual:

- cron scrips
- repair permissions
- zap PRAM

if nothing works, backup and clean install :confused:

that's what I would do, otherwise take it to the dealer for warranty (might be defective...)


Jan 14, 2005, 12:14 PM
Hey Blue

Found this article (http://www.insanely-great.com/news.php?id=3816)

Some early adopters of the iMac G5 are reporting excessive noise from fans, MacFixit reports. Although only a small number of users appear to report the problem, there is some evidence that some 17" units are somewhat loud.

Conversely, it seems few problems have been reported with the 20" models, although Apple's own Discussion Boards contain reports of owners of the 17" iMac returning the unit.

One reader, who mailed MacFixit, returned his troublesome 17" model to his local Apple Retail Store and swapped it (and some cash, presumably) for a 20" iMac.

Analysis: It doesn't appear, at this stage, that the iMac-17's fan noise is a real issue, except among a small number of what must be very early production units. Let us know how you go with yours.

And this from ThinkSecret (http://www.thinksecret.com/news/g5noise.html)

Apple officially responds to Power Mac G5 noise problem

By Nick dePlume, Publisher and Editor in Chief

February 20, 2004 - While customers grouse about their Power Mac G5's buzzing and beeping noises, an internal Apple service note acknowledges the problem and states that Apple will replace the power supplies of affected machines.

The noise problem first cropped up this past fall, but online discussion indicates that the issue is still relevant. Apple has revised the engineering of the G5's 600W power supply and replaced a number of units, but up until recently the company deflected many of the complaints by blaming grounding issues.

One thread at Apple's own forums reached over 1000 posts this month before a company moderator closed the discussion, instructing customers to review a tech note about ground loops, and then to contact AppleCare if the problems persist. "Those of us that are audio professionals quickly dismissed this info as being non-relevant because we know how to identify and resolve ground loops," one G5 owner posted earlier in February. "Apple's response to this issue has been appalling."

The Apple document, dated this month and recently obtained by Think Secret, confirms that the humming, buzzing, or high-pitched beeping noises exhibited by some dual-processor G5s are caused by their power supplies.

In the service note, Apple says that the power supplies typically emit acoustic noises during low-usage times when the processors idle. In addition, some G5 users have noted the noises during times of network activity or while moving desktop icons, according to the document.

"Apple is aware of this noise and is willing to replace the power supply for customers who are dissatisfied," the document says. "The beeping is a normal function and will be reduced, but may not be eliminated, even if the power supply is replaced." However, Apple says, customers who do not wish to have their power supply replaced can change their processor's Energy Saver setting to Highest, which "may increase fan noise" but will reduce the noise level as well.

(Some users had experimented with disabling the G5's "Nap" mode using the developer CHUD tools, but Apple reportedly does not recommend that approach.)

In the document, Apple also said that a second type of sound exists, but unlike the acoustic noise, this digital noise is heard over the G5's audio signal. The sound reportedly originates from AC-powered devices connected to the computer. The document says Apple is "aware" of the noises and "is willing to replace the power supply for customers who are dissatisfied." However, the company says, "proper grounding is generally required to truly eliminate the issue," and customers should see Apple's Audio Noise Troubleshooting Guide -- the same page Apple has pointed to in the past -- to potentially eliminate the noise.

Meanwhile, some customers report that the revised power supplies aren't fixing the problem satisfactorily, suggesting that it could be some time before the G5 noise issue is fully resolved.

Not much help for you I'm afraid.

Woof, Woof - Dawg