I found a solution to why my laptop fan was running constantly and running my battery out in an hour. This problem is common for MacBook users and many websites and forums suggest restarting, installing fan regulation software, resetting PRAM, etc. None of these really work, but the solution is very simple.
Since laptop users are mobile, they're frequently using different printers. When sending a document to print sometimes my MacBook selects the wrong printer, when it doesn't print I select a new printer and print again. But I forgot to delete the print job sent to the first printer, so my Mac keeps looking to print at the other printer causing the processor to heat up and the fan runs constantly.
Therefore, open System preferences go to Print & Fax, then select the printer that has a document in the queue, delete the print job and the fans shuts off within a minute -- and stays off.
The laptop will stay quiet and cool, the battery will last the usual amount of time, and MacBook mobile life is good again.
If you notice that the left speaker on your MacBook Pro or MacBook has gone silent, make sure to check the following settings before making an appointment with the Apple Store for a hardware inspection:
System Preferences » Sound » Input: If 'Use Ambient Noise Reduction' is checked, simply uncheck it to unmute the left speaker.
Applications » Utilities » Audio MIDI Setup: Go to Audio Devices, and select 'Built-in Output' from the Properties For drop-down dialog. Now look under Audio Output and make sure Channel 1 isn't lowered or muted. Note that this program doesn't report the 'Ambient Noise Reduction' setting as Channel 1 being muted. (Some users have reported that iChat AV may lower the left speaker's volume drastically for voice conferences, so you may need to repeat this step after each use of iChat AV.)
The couple of minutes it takes to perform this basic checkup is certainly worth saving a trip to the Apple Store.
Okay. I spent waaayyy too much time looking for the answer to this problem, so I'm posting this for others in the same situation. I am the Resident Geek at a middle school, and one of our G4 iBooks (1.33GHz) would start up, then immediately go to sleep. If left for a day without power (battery removed and machine unplugged), you could log in before it went to sleep. In all of my searches, including a hint here from 2007, the reed switch seemed to be mentioned a lot...but there was also confusion on its location, and whether the logic board was to blame.
After taking apart the laptop and unplugging the reed switch -- which is located on top of the optical drive -- I confirmed that to be the problem. A new one for $15 (Google it!), and I was back in business. Hopefully this will help others.
Also, I will post the following as another hint, for others taking apart things such as laptops: the issue of leftover screws. The secret to a successful reassembly is the logic behind disassembly. I have found that a rough drawing of the different layers (bottom case, metal shield, etc) with two-faced tape over the drawing to stick the screws to their respective locations does the trick. I know that iFixit has detailed manuals, but given that their manual did not list the reed switch in the correct place, I was reluctant to rely on their screw placement.
If you are into hardware modifications, here's one: it's possible to have the media keys (e.g. iTunes controls, Dashboard, and Exposť) which came with the last pre-unibody MacBook Pro on your older MacBook Pro, either by changing keys only, or the keyboard assembly. Who needs a Num Lock key anyway?
This mod is quite simple on MacBooks, as the system will recognize the new (relatively cheap) top case and maps keys accordingly. On a MacBook Pro, however, unless you change the whole top case (preferable, but much more expensive, and possibly impossible with the oldest MacBook Pros, as they have Bluetooth inside the bottom case), the system gets the needed product ID from the top case. So a software mod is needed.
After some digging in the system, I found the file in question: /System » Library » Extensions » AppleUSBTopCase.kext » Contents » PlugIns » AppleUSBTCKeyEventDriver.kext » Contents » Info.plist. Don't forget to back it up first, and then modify it as super user.
Go to System Profiler and find the product ID; it's located Hardware » USB » Apple Internal Keyboard / Trackpad » Product ID. For example, on my European late 2006 MacBook Pro Core 2 Duo, it's 0x021b. Convert that value to decimal, using Calculator (View » Programmer first, then Hex). That's the Product ID of your top case (mine is 539).
The following tip is something that I find very useful for myself, and that only works for Macs that can use four-finger Exposť mode on the trackpad.
While using a four-finger down swipe on the trackpad to trigger Exposť, don't release your fingers just yet -- hold your fingers for one second after swiping, then release them. When used in this manner, Exposť will activate, then turn off by itself when you release your fingers. This also works when activating Dashboard with a four-finger up swipe.
This is good for briefly glancing at information in other windows or the Finder.
[robg adds: Exposť and Dashboard can actually be used like this with keyboard-based activation, too -- just hold down the activation key (F9, F10, F11, F12) until you're done using Exposť or Dashboard, and it will close automatically when you release the activation key. We covered this keyboard-centric behavior for both Exposť and Dashboard in previous hints.]
I needed to get my MacBook Pro running again after the hard drive failed, but the only drive I had available was a desktop 3.5 inch SATA unit.
So I opened up the MacBook Pro to see what could be done. Unfortunately, the onboard SATA connector won't accept a standard SATA cable. However, all you need to do is chop off some of the excess plastic on the SATA cable, and it works.
Note that you do need an external power supply for the hard drive, as the internal source doesn't supply the full 12v required.
Pro: Backup system is viable
Con: No longer a laptop
[robg adds: I haven't tested this one, and hope I never need to do so!]
Using my MacBook Air (first gen), I mistakenly hit option-F11 (instead of fn-F11 to disperse all windows), and found I got taken to the Sound System Preferences panel. I tried this for the other Fn-keys and sure enough, I can access Displays, Exposť & Spaces, and Keyboard System Preferences by just adding the Option key to the Fn key.
It's easier than right-clicking on the desktop to then access Change Desktop Background, which is not much faster than mousing to the Apple menu.
[robg adds: We've covered some of these shortcuts before, at least in passing, for older OS releases and older keyboards, but I don't think we've covered this particular implementation ... my apologies if this is a duplicate, however.]
With so many complaints about FireWire disappearing from the MacBooks, I wondered if large files could be copied using just an Ethernet cable. It was successful, and the transfer was rapid -- less than one minute to transfer 1.8 GB.
I used an aluminum MacBook connected via Ethernet cable directly to an aluminum iMac. AirPort cards were turned off on both computers, the Ethernet connections were active, and file sharing in the Sharing System Preferences panel was on. Under Shared in Finder, the computers recognized each other, allowing me to copy from one computer to the other.
[robg adds: This is a fairly basic tip, but I don't think we've covered it here before. Basically, the Mac OS is smart enough to set up a functional network if you connect two machines together using Ethernet (or FireWire) cable. Once connected, transfers will happen very quickly. Unfortunately, this doesn't help with the larger MacBook/FireWire issue, which is that you can't connect FireWire drives, video cameras, etc.]