MacBook Shutting Down Randomly

[northy124]

Hey guys,

I have a MacBook which has recently been shutting down when it feels like :/ this all started a week or two ago (well not the shut downs but other issues that I'll get too), basically the fan I think has been knocked as it is bumping the top or something as the whirring is getting loud and it sounds like every now and again it hits something

Also CPU usage seems to be averaging out at 20% for Safari and 100% for HD Video where as it used to be very small amount for Safari and 30 - 40% for HD

Now it has started to shut down I am getting rather pissed off with it and was wondering if there is a way to find out how to sort it myself as this is a 3(?) year old MacBook and I don't intend on spending money for repairs just yet as I am saving for a new MBP and a holiday to LA

So is there a way to self diagnose?

Northy

Edit: Could it be over Heating? (it is in ºC)

 

[Pax]

Can you tell us what model Macbook you have? Some of the early ones had heat problems. You can find out what you have by going System Profiler and looking at the model identifier.

I suspect it's overheating because your fan is stuck.
The data you posted shows that your CPU is idle & is only drawing 3 Watts.
And still your CPU is quite warm at 73 C
Also your heatsink is very hot at 70 C, nearly the same temperature as your CPU.
That tells me that the fan isn't taking heat away from the heatsink properly.

When your CPU is working at 100% it draws 10 x as much power so the CPU temperature will shoot up very fast and it will shut down to protect itself.

My 3 year old Macbook has CPU temperatures around 60 C when doing nothing, with the heatsink quite a bit cooler than that.

Fortunately fixing the fan should be pretty cheap.

I think a way to tell for sure is to play an HD video and watch the CPU temperature. If there is a fan problem it will increase very very fast to 90 C or 105 C (depending on what model CPU you have) then the CPU will slow down its clock so the video might stutter, and then at 110 or 125 C it will all shut down, black screen. It might only take a few seconds before this happens so you'll have to watch carefully!

PS what tool are you using to get this temperature and power data? Look nerd-tastic!

 

[northy124]

I have the 2.16GHz C2D MacBook 2,1

So I would have to pay to repair my fan/heatsink? damn kind of want to avoid that.

It just shut down just now but it was at 81ºc not in the 100's so :/

I am using iStat for the data

 

[Pax]

OK, I think there are at least 3 possibilities,
(others may have more ideas)

1. Bad fan - overheat. As I said above your Mac does seem quite hot even when idle, but the early Macbooks did get quite hot inside. The fact that the fan is making a noise kind of hints at this

2. Hot or bad RAM. Try unplugging and plug it back in. The Web will tell you how, but you need to press those sticks in HARD. Til you think you're going to break them.

3. Random Shutdown Syndrome.
http://blogs.zdnet.com/Apple/?p=274

This affected the early Macbooks. It certainly affected my CoreDuo bought in early 2006. The problem was IIRC related to a temperature sensor wire which ran across the heatsink and melted in the heat. The Mac became unable to properly control its temperature causing the shutdowns.

As I say it definitely was a big problem for early 2006 Macbooks. IIRC it took them a loooooong time to work out a fix for it, because I had to wait months to get a new logic board. So it is possible that it affected the Macbook 2,1's as well.

4. something else I haven't thought of, but someone else will.

Yes you would have to pay for a new fan. It's not a hard job to replace, if you have some electrical skills you could probably do it yourself. But if you're not 100% confident you should pay someone Apple certified to do it. I would guess at $100 but that's a wild guess.