Chosen Solution

Hi there, since some time my MacBook Pro 7.1 (Late 2010) turns off randomly (like you press the power button for a few seconds while running). I have already tested the following things: Disconnect the battery (run from MagSafe)Disconnected MagSafe (run from battery)Replaced HDDDisconnected ODDTested the RAM modules seperatelyTested the RAM slots seperatelyTested with Mac OS 10.6, 10.7 and gParted (Linux Live Distro) Nothing of this has fixed the problem. I think, it’s an heat related problem. I opened the MacBook and turned an ventilator directly to the Logicboard (see this fotography). With this testcase, everything worked fine. So I’ve installed temperature monitor. Even without the ventilator, the temperatures seem fine. Then I’ve put the CPU under a stress test with the terminal command yes > /dev/null (I’ve entered this command twice to stress both cores). I noticed that the fan hasn’t speed up, even when the core reached about 105°C. The fan itself works fine. Then I’ve installed a software fan control. This temporarly fixed the problem when I turn on the fan @ 6000rpm (max. Speed) but this isn’t an acceptable solution. I have tested the system with the fan @ 3000rpm (the fan is good hearable) under idle too but it still turns off. In the meantime I’ve brought the MacBook to an certified apple support. In a short demonstration the fan spinned up there under stress so I thought the problem has solved itself and took the MacBook home (without “repair”). At home it turned off randomly again (but the fan control seems to work again). Does anyone has an idea what it could be? Update I forgot to mention that I’ve already done a PRAM and SMC Reset. How precise are the temp sensors? I’ve looked at every temperature and they should be okay when the macbook turns off (in the range from 35 to 65°C). Update Another update: the fan only spinned up, because there were some leftovers from fan control. After following the uninstall instructions, the fan doesn’t spin up even at more than 80°C (CPU). Could it possibly be a firmware error or some broken temperature diode? Am I able to reapply the latest firmware update? @Dan: I’ve disconnected the battery for testing purposes, so the battery could not be the problem. There were not dust at the fan so I do not think that there’s any “dust problem”. Another interesting thing: the first time I power up the macbook after the night, the system runs for a much longer time than when I restart the machine after the random turn off. This is another indicator for a temp related problem. But as I’ve stated: the temperatures look okay with Temperature Gauge and TemperatureMonitor. So possible there is a short when some metal expands by temperature? Update So what are your recommendations? Is it worthwhile to bring the MacBook to the Apple authorized service provider to let him do a hardware check? Do you think that reapplying termal paste could fix the problem? When nothing helps… would you recommend me baking my logic board (when I have nothing to loose)? Update I have now reapplied the termal paste, that doesn’t fix the problem. But now I got another problem too: the internal monitor doesn’t work anymore. It flashes only one time when starting the macbook but then turns off. I’ve already checked the monitor cable (near to the magsafe connector) but it looks correctly connected. Some ideas?

As you have stated you tried resetting the PRAM & SMC settings and your CPU temp is normal (when its together using monitoring software). You also stated you brought the system in to an Apple authorized servicer and they couldn’t find any problem (heat or otherwise). The thermo couplers Apple uses are pretty reliable and they use multiple ones so you should be OK if they are within the normal range. The fans do have some lag in ramping up and down so I wouldn’t worry they don’t jump into high speed when you think they should. As you got a newer system the thermal paste should be OK and the pic you have doesn’t show if you have a lot of dirt buildup inside (and you don’t say you did either) So I don’t think this is the correct direction in your problem. I’d first rule out software as it can cause the CPU to run hot if something is running that shouldn’t be. When you replaced out the HD did you make an image of the old files on to it? Or did you re-install everything from original program CD’s or from the App Store? If you did an image you could have something messing up your OS. Have you run Mac OS Update in the last few weeks? If not I’d start there. As there has been some OS-X Malware out there. Do you have any antivirus running on your system if so make sure you have the latest updates applied and check your system out. The next thing I would do is check if any OS or browser add-ons are running that need updating or disable them. Did that fix things? Are you running Linux as a dual boot setup or running a virtual machine under OS-X? you talk about running gParted and running Linux Live Distro. Could the OS boot blocks be messed up some how so your page files are getting corrupted (VM mode). Try running Apples Disk Utility program booting from a second HD or the OS install DVD. Lastly, I would run Apples Activity Monitor to see what is running that is consuming the CPU when the system is getting hot and you’ve stopped running any apps. Let us know what you find - Good luck