T40 overheats, powers off

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wsm · #1 Post by **wsm** » Fri Jul 20, 2007 4:35 pm

4 yrold T40 apparently starting overheating about a year ago. After some usage it dies with no error. And it stays up less each time until it cools.

Two days ago I conclusively determined it was heat because
a) I swapped memory and disk and it still fails
b) take off keyboard and touchpad face plate, leaving the unit open to a ceiling fan, the unit does not die. put the stuff back on and put on a load (scandisk, etc) and it dies.

Unit extensively cleaned of dust and cpu heat sink redone with the standard goop (but not arctic silver). Fan seems to be operating normally. Air output is not hot. Nothing I can safely touch is hot to the touch, including caps. North bridge is considerably warmer than the copper heat sink, almost hot to touch.

How do I determine precisely the problem - fan/speed, bad temp sensor, overheating north bridge (it doesn't have a heat sink and I've read this can develop probs), etc.

And what are nominal operating temps and fan speed?

Thanks

mitchellst · #2 Post by **mitchellst** » Fri Jul 20, 2007 5:42 pm

If you're still using the original fan, I'd try replacing that first. Get a long fan if you don't already have one. It can't hurt.

That being said, if you can't find an obvious hot spot, then it could be a failing motherboard. It does sound heat-related, but it could be either.

#3 Post by **richk** » Fri Jul 20, 2007 6:02 pm

I would remove the fan and clean off old thermal grease with denatured alcohol, apply new grease and reseat the fan.

wsm · #4 Post by **wsm** » Sat Jul 21, 2007 8:32 am

what is a "long fan" and how is it different from the stock fan+heatsink?

#5 Post by **richk** » Sat Jul 21, 2007 9:42 am

The long fan has a thermal pad that contacts the graphics chip. It provides cooling for the graphics processor on machines that have a graphics controller other than the standard ATI chip. What model do you have. It will be on a sticker on the back, probably something like 2373-XXX

wsm · #6 Post by **wsm** » Sat Jul 21, 2007 11:27 am

This T40 is model 9cu with long fan. I also have a 44u.

Good links and info at
http://forum.thinkpads.com/viewtopic.ph ... ink+bridge

Perhaps the easiest modification in one of the links** is to block the infiltration of air from the PCMCIA slot, to improve airflow through the rest of the unit.
**http://linuxfocus.org/~guido/gentoo-tpt43p/cooling/

wsm · #7 Post by **wsm** » Thu Jul 26, 2007 3:41 pm

I need a next step after what I've done below

opened it all up, again
* second cleaning of dust and cleaned off heatsink with alchohol
* redo heatsink paste and screw heatsink back on
* closed off PCMCIA air infiltration as suggested by http://linuxfocus.org/~guido/gentoo-tpt43p/cooling/

powered up (AC only, no battery), died ~30 sec later while I was editing BIOS settings

* opened it up within 5 seconds (I hadn't put any screws in)
* checked all components, including CPU with heat sink off - everything is basically cool to the touch.

power circuit? (I've already tried a second power supply)

FTC · #8 Post by **FTC** » Thu Jul 26, 2007 4:27 pm

Hi, first of all I'd try installing the tpfanspeed and try to identify if any of the sensors in the thinkpad detects more heat than what is normal... at least you will know which part of the thinkpad to look further, PCMCIA, Battery, CPU, bus, ...

Other than that and supposing it is not effectively the CPU and/or blocked heatsink or broken fan, it could be the wireless card (have heard some cases of those overheating and playing havoc with the machine), or the battery itself... also a bad/loose contact that does intermitent connection based on temp could happen. Just to be in the safe side I'd reseat the memory and the miniPCI cards (modem/BT and/or wireless) also.

wsm · #9 Post by **wsm** » Thu Jul 26, 2007 5:21 pm

[quote="FTC"]Hi, first of all I'd try installing the tpfanspeed and try to identify if any of the sensors in the thinkpad detects more heat than what is normal... at least you will know which part of the thinkpad to look further, PCMCIA, Battery, CPU, bus, ... .[/quote]

yeah, that's what I was hoping to get to. I already had something installed MBM and CPCool installed before this began and fan and all monitored temps seem OK.

[quote="FTC"]
Other than that and supposing it is not effectively the CPU and/or blocked heatsink or broken fan, it could be the wireless card (have heard some cases of those overheating and playing havoc with the machine), or the battery itself... also a bad/loose contact that does intermitent connection based on temp could happen. Just to be in the safe side I'd reseat the memory and the miniPCI cards (modem/BT and/or wireless) also.[/quote]

that was already done - even started up networking cards removed and both bios settings disabled.

The primary symptom here is it dies at increasingly shorter intervals, and can be induced by loading up the disk+processor by running virus scan and defrag - although it also happens with no disk activity at all, eg while sitting in bios. I am currently running the disk and memory that were swapped with another unit - so it is not those items.

wsm · #10 Post by **wsm** » Thu Jul 26, 2007 5:24 pm

in addition to being able to die while in bios, can also happen at "dead idle" in windows - i.e. unattended and "nothing" running except what it starts with. I also changed bios to disable quick startup so it runs its longer tests. IBM supplied diagnostic tools were also run more than once.

T40 overheats, powers off

T40 overheats, powers off

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