MacBook Pro turns off randomly
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 HDD
- Disconnected ODD
- Tested the RAM modules seperately
- Tested the RAM slots seperately
- Tested 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?
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).
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?
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)?
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?
Is this a good question?