Computer shutting off for no reason

[thefragger]

Hey,

I took apart my T40p to clean it (it's spring time!) and I thought I'd pull out the fan to see how hard it is to do-- I need to get a new one anyways and thought I'd get a feel for it-- it's pretty easy. I reassembled everything and turned the laptop on.

Great, it still works... except now, the fan is on all the time... and about half an hour in, it turns off. Cold.

I turn it back on, and about 45 minutes later, it turns off. Again.


What did I do to my Thinkpad?! I'm going to to get some Artic Silver tomorrow and see if it's not an overheating issue, but I'm pretty stumped.

Any thoughts/suggestions are more than appreciated.

Cheers!


Update!
I downloaded TPFanControl and it shows my CPU temp thrashing about wildly. It'll idle at 58° then when I start Firefox (which only takes a moment) it'll spike to 72° and now, while I'm typing this message, it jumped to 81°, seconds later, it's down to 46°.

The air is cold.

What the hell? Is something loose?


I'm going in.

[richk]

It certainly sounds like overheating. You need to remove the old thermal grease and reapply new. I use denatured alcohol to clean.

[jdhurst]

This will not shed light on the shutdown, but CPU temperature does fluctuate a lot. It can spike up really quickly under any load and then back right off again. It usually takes a bit longer to cool off than to heat up. Also my fluctuations are in a bit narrower band than yours. ... JDH

[thefragger]

I was going to go out and get a tube of Artic Silver, but all the stores are closed, so I pulled a dirty, dirty hack; toothpaste and white grease.

so far I'm stable at 30°-- this is a temporary thing until I go out tomorrow and get the good stuff.

[jdhurst]

Even after that, your temperatures are wild. On no occassion has my T41 ever fallen as low as 30 - that is really cold for electronics that generates heat. Even a 10 pound iron core power transformer will idle along a 30 doing nothing. And my T41 has never risen as high as 81 under any conditions, including running the CPU for an hour or more at 100 percent. Strange temperatures indeed. ... JDH

[thefragger]

it's the minty freshness?

it's around 42~44°C right now.

it was hitting 80 without any hs contact.

**heatsink