A few months ago, I dropped my 15″ MacBook Pro from about 3 feet. Upon immediate inspection, I only noticed a small dent near the DVI connector, but I figured that was the extent of the damage since the computer was off (or at least in sleep mode) at the time.
The next time I turned on the laptop, it went to sleep after a few minutes. I would power it back on and it would go to sleep again seconds later. This repeated again and again. I decided to let it sit overnight. The next morning, I powered it on and it would stay on for about 15 minutes before it would go to sleep, only this time when I would wake it back up the screen would not come back on. This happened for two weeks before I could get a new laptop (thanks State Farm Insurance, for covering a large chunk of the purchase). In the mean time, I used the machine with an external display. For whatever reason, when the DVI port was in use, the machine would stay awake.
I figured the problem had something to do with the “sleep sensor” in the MacBook Pro. When the computer would stay awake, the screen worked fine and the computer itself worked fine. My thought was that the computer thought the lid was constantly closing and so it would go to sleep.
I thought the “sleep sensor” was located in the latch or somewhere in the front of the laptop, but after poking around on the Internet and on the machine, I found out that its located on the back of the right side of the keyboard, right in the middle. It is something that is commonly called a reed switch. It sends an electrical impulse to sleep the computer when the force of a magnet is felt. The magnet is located in the bezel halfway down the display on the right side. Confirm this by placing a paperclip in that location! When you close the lid, the magnet lines up with the sensor on the underside of the right speaker grill and tells OS X to go to sleep.
The paperclip shows the location of the magnet portion of the reed switch on the MacBook Pro
If you take the top of the laptop off, you’ll see the second part of the reed switch with a three-wire connector leading to the main keyboard ribbon cable.
The sensor of the reed switch is located just under the right speaker grill.
Close up of the reed switch
I removed, cleaned, and reinstalled the sensor, and now the machine has been working on battery power for hours without a problem (I’m typing this entry on it now). I’ll update this post if something goes awry, but if you’re having weird sleep problems and think you’ve tried everything like the dozens of other people that have posted on Apple’s discussion boards, try cleaning the reed switch and make sure you don’t have strong magnets near the right side of your MacBook Pro.
Hi Greg,
I am having a similar issue with my MacBook Pro 15″: the computer powers and stays powered on, but when it is closed all the way it won’t go to sleep (it just stays on). Also, while the lid is latched down if I put my fingernail in between the lid and the lower case the sleep function works! Puzzling. Any suggestions? How did you clean your reed switch anyhow? I’m about to perform surgery…again.
Thanks!
@Jay: I completely detached it from the ribbon cable near the trackpad, blew some compressed air over everything, and also touched magnets to the bezel around the screen where it touches as well as the part under the speaker grill. A good deal of luck was probably involved, but the machine is working flawlessly to this day.
I’ve read reports from other people that the part of the switch that rests behind the screen bezel will shatter. That could very well be your problem, and if it is, that’s a lot more surgery than I had to do. I’d love to see some pictures if it gets that far. Let me know how it goes! The more resources online, the better.
Hey,
I have a little different issue. One of my “Hooks” doesn’t drop down when latching. The one on the right side. I think it is because the magnet is not stron enough. I was looking at your pix to look for the magnets, but don’t see them. I figured they would be ohn the underside of the lid. I can place something metal near where they are and feel them, but the one on the right is not strong enough the pull the latch down. This makes the lid look warped, which is a major complaint. My lid is not warped, it just looks that way because only one latch is latched. Do you have a pic of those magnets. I want to see if I can fix mine with a stronger magnet.
I don’t personally have a picture but there are tons of resources on the web regarding the MBP latch. This video from Small Dog has a breakdown of the latch mechanism. The magnet is right in front on the bottom though, where you’d expect it to be, and it’s pretty easy to get to/replace if that is the problem.