After replacing power jack, T42 shuts off randomly

[harbong]

My T42's power recently stopped charging the battery, so I went about replacing it with one from a defunct T40.
One of the screws that goes through the bluetooth card would not come out, so I wiggled the jack in under the metal frame and wired it up and pieced the laptop back together. It worked fine.

However, I have noticed that the temperature monitor is jumping in temperature frequently, from say 77C to 90C back down to 82C for example. This causes the fan to rev up and down fairly often. I have TPFC on Smart 1 but have set it to BIOS to avoid this.

Also, I have had MS Security Essentials' MsMpEng.exe process begin to eat up all of CPU and up to 150 MB on loading, presumably causing the temperature to spike over 92C and then my T42 just shuts off. I became very frusterated at this and ended up disabling the software last week.

since then the temperatures have been a little lower usually around 78-86 but the shutting off still happens at least once a day. It is not when I move the laptop, just using it on a desk. The temperatures still jump up and down more than 10-15 degrees frequently.

Does the temperature sensor shut down the laptop if it gets too hot? Could I have damaged the sensor during my repair? I am confused and would like to know if I can do anything to stop the frequent shutting down.

[RealBlackStuff]

It would definitely do no harm to clean the CPU fan, and refresh the thermal paste between CPU and cooler with Arctic Silver 5.
The thermal sensors aren't anywhere near the power jack, so it must be something else.

[irus]

yessir some cleaning is due!

[harbong]

thanks guys, I reapplyed thermal grease to the heatsink and cpu two nights ago, and it hasn't gotten over 70C since!

how often should I check to reapply thermal grease?

[RealBlackStuff]

Just keep an eye on the temps.
If they stay consistent, don't do anything.
No need to replace it anytime soon, unless you used some cheap gunk.