Mac Mini Bluetooth working only intermittently

Some Mac Mini users who have Bluetooth keyboards or other devices connected to their computers may experience a problem in which Bluetooth stops responding.

Apple Discussions poster BJRaithby writes:

"I keep losing the Bluetooth wireless connection between my Apple wireless mouse and keyboard and my Intel Mac mini (which is running Mac OSX 10.5.5). I tried re-booting but it doesn't always come back. Looked in System Preferences, but if the connection is lost, Bluetooth has disappeared as if not installed. If the connection is present then all seems OK. You can check battery levels etc. If left to itself Bluetooth can re-appear sometime later as mysteriously as it disappeared, maybe after half an hour or so."

For many users, this problem can be intermittent, but it is also possible that Bluetooth has stopped working altogether. Affected users have tried restarting their Macs, as well as resetting the PRAM and numerous other standard fixes, but the problem continues. Other users have noticed this problem and attributed it to overheating, but these users also noticed the problem occurring when the computer was started from a cold boot.

This problem is a hardware issue that is a result of a lost connection between the Bluetooth module and the computer. The Mac Mini does not have Bluetooth directly on the motherboard; instead, an expansion card is connected and mounted over the motherboard. This daughtercard contains both the bluetooth as well as AirPort modules, and it is possible that in servicing the computer or even inadvertently jarring the computer could cause the connection to dislodge partly, resulting in this dropout behavior. While it is more unlikely that heat generation could cause this problem, there is the possibility that components expanding or warping slightly because of heat could contribute to it.

In addition to connection loss, there could be problems from interference in the signal if the Bluetooth antenna has fallen out of place, and therefore the way users have overcome this problem is to adjust the bluetooth module's connections and antenna placement.

Fixes

Reseat the bluetooth module and daughtercard The fix for this problem is to open the computer and ensure the connections for the bluetooth module are properly seated. Opening and servicing a Mac Mini is a little more complicated than larger Macintoshes, and it is recommended that users take the computer in to a service center if they are not comfortable with the procedure.

For users willing to tackle this problem themselves, here is a detailed procedure for opening the computer and accessing the Bluetooth module.

Here is a well-done picture guide (with video as well) for opening the Mac Mini.

When the computer is open and the daughter card is removed, as per the instructions, users should ensure that both the Bluetooth module is firmly and properly connected to the card, and that the card is then firmly attached to the motherboard.

Adjust the antenna Both the Bluetooth and Airport modules have antenna cables attached to them, which are routed along the sides of the computer to the antenna modules, which are placed above other components in the cases. This article shows pictures of them pretty clearly, and users should ensure they are attached and the cables are not tucked under other components or otherwise out of place.

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