How do I diagnose a narcoleptic Mac?
My workhorse machine is a 2.5 GHz A1260 with 6GB RAM and an SSD swapped in for the optical drive. I love it, scratches and dings and all. I've lost track of how many times I've disassembled it, and it's missing a few screws.
For the last six months or so, the sturdy machine has had intermittent narcolepsy: it goes to sleep on its own, with no provocation, whether plugged into AC power or not. The behaviour started with a dying battery, but I'm running on a brand-new one now.
I haven't cared about the issue so much up to now— it only happened once a day or so, and the computer's brief naps gave me a good excuse to go stretch. But today, it's gone to sleep three times thus far and shut off with no warning twice. It's been plugged into an 85W AC adapter the whole time.
This issue may be similar to Random MacBook Pro shut down, but we never saw a resolution on that.
- Goes to sleep randomly a couple times a day, with ever-increasing frequency
- Loses power, even while plugged into AC with new battery
- Tried at least three batteries, including new battery
- Used multiple 85W power adapters
- Reproduced issue at multiple locations, so it's not the mains power.
- Removed ambient light sensor.
- Installed known-good ambient light sensor.
- Removed sleep sensor.
When it shut off on me today, it was plugged into power (glowing amber) and my battery was at about 80%. Started it back up, ran for about 5 minutes, then shut off again. Since then, it's been working fine. The computer hadn't been running much yet and wasn't warm, so it's not a heat issue.
Today, it started shutting off within 2 minutes of boot. I'm typing this on another machine. Taking it apart now; I'll start swapping components.
It's not the ambient light sensor or the sleep sensor (tested known-good parts on both). I swapped in a new upper case an hour ago, and it hasn't shut off since. I'm crossing my fingers, but not overly-optimistic yet.
Some things just can't be fixed! I hate to say it, but I was forced to give up on this machine and upgrade. We parted out the old machine, so it didn't end up in the dump, but I never did figure out what the problem was.
Sometimes, with the tremendous technical complexity of these machines, you have to put the problem down to something at the board-level. I'm pretty confident replacing the main board would have fixed it (I tried everything else that made sense), but at that point I was better off recycling the machine and upgrading. Thanks for all the help with the issue!
Try relpacing the ambient light sensor. Apple Part # 922-8353 for the left.
This sounds similar to the "Narcoleptic Aluminum PowerBook Syndrome". Symptoms include the PowerBook suddenly entering sleep mode, no matter what the battery level is or if it is plugged in. One cause is the ambient light sensing, and associated instruction set coding, with possible keyboard backlight and sleep light issues accompanying the so-called "narcolepsy". Another cause is the trackpad heat sensor monitoring the trackpad; system logs report "Power Management received emergency overtemp signal. Going to sleep." To correct this, service groups will often replace the motherboard or power converter, but the actual fix (depending on the model) for the first cause is to replace or remove the left or right ambient light sensors; and for the second cause, disconnect, remove, or replace the heat sensor, or the entire top case which holds the trackpad heat sensor. Alternatively, there are reports which detail success in removing certain sensor kernel extensions or rebuilding the kernel using the Darwin Open Source project after commenting out the relevant sleepSystem() call; though permanent solution of the sleep issue in this manner is little documented.
Toss system pref's
Funky .plist files can cause all sorts of goblins. Of course you have already set "Computer sleep=Never", "Display Sleep=Never", unchecked "Put the hard disk to sleep when possible", "Slightly dim the display when using this power source". (battery) and unchecked "Automatically reduce brightness before display sleep".
If this answer is acceptable please return and mark it.
Incidentally, have you checked that the spotlight search on the SSD may be so "fast" that the processor actually overheats? I have had that issue with an SSD installed into an A1260/Macbook Pro/Core 2 Duo. Overheating can cause shutdowns.
ncidentally, have you checked if the spotlight search on the SSD could be so "fast" due to rapid data transactions with the SSD that the main logic board actually overheats? I have had that issue with an SSD installed into an A1260/Macbook Pro/Core 2 Duo. Overheating can cause shutdowns.
P.S. you can download temperature monitor programs for your Apple on the internet for free.
I've had the same problem with my macbook pro core 2 duo (2.6 ghz I think). I've now brought it in to the Genius bar FIVE times. So not happy about it. They have no idea why its doing it, and they just keep replacing stuff and giving it back to me and saying its fixed. But wont give me a new computer. They've replaced the batttery, logic board, heat pipe(?), and some of the power management components, and reinstalled the os twice.
error code -81. They say its not in the book, and they dont know what it is. Anyone have any tips for the geniuses?
Ambient light sensor? Hmmm. Maybe I'll suggest that to them since they're still working on it at teh shop. thx
Resetting the logic board and testing and replacing the PRAM battery would have been my first step. Then I would have made sure the firmware was updated and properly updated and rebooted on restart. I am a certified Apple tech and found out a lot of people don't know about other good troubleshooting steps involved for proper diagnostic fixes. Yanking and resetting the RAM along with zapping the PRAM is so a great way to resolve some issues. When it come to problems with the logic board more in depth troubleshooting steps are taken. Best of luck with your next Mac.
Hi I am not sure if this helps but if you are still encountering the same issue can you try to see if the DVD drive still works correctly after the shutdown? I.e. read a disc.
I have just replaced my old late 2008 Uni-body MacBook Pro because it would randomly put itself to sleep. The fans would be running on full power and the CPU temp would be through the roof ( I was monitoring it with Istat Menu meters) also it was plugged and charged so that was not the issue.
I could tell when it was going to go to sleep as the connected external discs would sleep first and then the machine would freeze and then go into a forced sleep.
Tried numerous SMC fan resets and also a PRAM reset, which should only be done in the most extreme issues as it is apparently quite dangerous or risky.
Turned out there was a fault in the Logic board and that it was not maintaining temperature control and thus the MacBook Pro was getting too hot and shutting down to protect itself, but not before taking out the DVD drive!!
Which echos the comments made above that it was a Logic board issue.