MacBook Pro (#13): Whining noises -- more fixes; AppleTalk printers not showing up over AirPort; more

CNET staff

Sept. 2, 2009 6:28 a.m. PT

4 min read

Whining noises -- more fixes Users continue to report, and we continue to cover, issues with various high-pitched whining noises being emitted by the MacBook Pro.

There appear to be various causes for this issue, and various associated workarounds.

In most cases, the problem has to do with power draw. When a certain amount of power is being drawn, the problem manifests. This explains why some users experience alleviation of the noise when toggling display brightness or turning off one processor using Apple's CHUD tools (which are included among the Developer Tools that ship with the MacBook Pro).

One reader writes:

"The noise increases over time and is very distracting. It disappears if I touch the metal screen cover, but builds up again- so it?s presumably some sort of capacitive effect. In my case, just touching the back of the screen causes the noise to disappear, but only temporarily."

More fixes

Turn off ambient light sensor MacFixIt reader, Michael, reports that turning off the Ambient-responsive keyboard lighting (go to the "Keyboard and Mouse" pane of System Preferences and uncheck "Illuminate keyboard in low light conditions" resolved the issue:

"I just wanted to chime in. I saw the suggestion about opening and closing the display and noticed that it would stop and start again as the ambient light under the keyboard would turn on and off. On it would whine, off it would stop. So I turned on the room light, the ambient light turned off and the whining stopped. So for me, anyway, the ambient light is what causes the whining."

Turn off one processor core Though not a viable long-term solution, some users have found that turning off one of the MacBook Pro's processor cores eliminates that noise.

In order to turn off one processor, you need to install Apple's Developer Tools (from the install discs included with your MacBook Pro). You will then have access to a System Preference pane labeled "Processor" that can toggle between single and dual-core operation.

Turn on Bluetooth Some users have eliminated the whine by activating Bluetooth then using one or more Bluetooth devices. This workaround reiterates the notion that most cases of whining involve power draw issues.

AppleTalk printers not showing up over AirPort An issue reported by a number of users that we have also experienced in-house involves the MacBook Pro not being able to see AppleTalk printers that are located on the local AirPort (or other wireless) network.

Several users have been able to workaround this issue by using IP printing instead of AppleTalk.

More on slow networking performance with VLANs We previously reported on an issue where Intel-based Macs exhibit significant data packet loss when connected to networks that also have 802.1q VOIP VLAN devices attached (such as VOIP phones from Cisco and other manufacturers), or when a VLAN setup is used.

Problems sharing Internet connection: Possible fix We previously reported problems sharing the MacBook Pro's internet connection via AirPort.

In some cases, this issue can be solved by going to the Network pane of System Preferences, clicking on "Port Configuration" and dragging the relevant sharing port ( Firewire, Ethernet) to the top of the list.

Keep power adapter connected when using external display with closed lid As noted in Knowledge Base article #86286, you need to keep the MacBook plugged into external power when operating with the lid closed and an external display attached.

Users who do not have external power attached may experience the system unexpectedly falling asleep.

Feedback? Late-breakers@macfixit.com.

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