T21 screen goes black

[abrogard]

Just two days before I go on a 3000km road trip where I need it to download the digicam pics my T21 has decided to switch off the screen and go blank a couple of minutes after startup.

This doesn't look much like a hardware fault, does it?

FnF7 doesn't fix it. Nor does FnF4, nor FnF3 (whatever that's supposed to do).

If I hang another monitor off it it won't work either. FnF7 doesn't make it work.

Leave the external monitor there and it reboots on both screens past the Windows 2K splash screen and then goes into checking file systems (because of the hard reboots I have to keep giving it)

The file system check takes quite a while (i.e. - longer than it takes for the screen to switch off if there's no file system check.. hence looking like software to me).

While it was doing this I tried to toggle screens with FnF7 but it didn't effect anything for the first three stabs (remember BOTH screens are currently on) and then both screens went black and the function keys wouldn't bring them back.

Right now neither screen will come on.

Any clues, guys?

Update: I detached the external monitor. Turned the notebook upside down and gave it a good shake. Detached the power cord. Tried again and it went into a series of reboots - getting past the splash screen 'IBM Thinkpad' and then booting.

Right now it has got as far as the win2k splash again.
Now checking the file system.
Now rebooted......

It might be little brown ants. We get untold problems with them. Can I open it up somehow and blow it clean?

I

[rkawakami]

<snip>...my T21 has decided to switch off the screen and go blank a couple of minutes after startup. This doesn't look much like a hardware fault, does it?

Could be hardware... if the CPU is overheating that might cause the system to lock up. Could also be some other components on the motherboard.

FnF7 doesn't fix it. Nor does FnF4, nor FnF3 (whatever that's supposed to do).

Fn+F3 is supposed to turn the monitor off. You can then "wake up" the system by pressing any key.

I would try removing the hard drive and see if you can get the system booted into the BIOS screen. If it does, leave it there for several minutes while you check to see if the fan is spinning and whether you have control over the Fn+F7 function. You can also try running PC Doctor on the system to see if that detects anything abnormal. Check this thread for some basic downloading and operating instructions:

http://forum.thinkpads.com/viewtopic.php?t=32096

If you need more help with PC Doc, just holler.

[abrogard]

Thank you for your informative advice.

The notebook is alright this morning so I think you might be right - it could be a heat related CPU problem. It was fiercely hot yesterday and the day before.

However the thing is inside, not outside, and shouldn't have gotten hotter than 40 Celcius, I'd say, at a guess (about 104 F). Would that be enough to worry a T21 CPU?

[rkawakami]

CPU temp of 40c is nothing to be worried about. When it gets up to 65-70c (constantly) then that's when to worry. I use MobileMeter on my systems to keep track of the CPU and hard drive temps. You can get it from here:

http://www.softpedia.com/get/System/Sys ... eter.shtml

[abrogard]

So I guess I must look for some other cause. The thing has booted up alright again this evening.

I have downloaded the meter and I will try it on the machine.

If the machine didn't have a recent history of screen blanking - ever since we tried it with an external monitor a couple of months ago - I'd suspect a recently acquired virus.

Very interesting. It shows my cpu at 47.0 C - considerably hotter than the air temperature, which is only 34.0 C at the moment.

Maybe the cpu did overheat on a particularly hot day. Though all the machine was doing was sitting there being fed electricity from the wall plug.

The meter also shows Frequency: 700Mhz. I thought my T21 was running at 1.7Mhz?

[dsigma6]

Ray, have you ever seen a system with temps of 65-70C that locked up- because of the heat? I don't know how you could be positive about that, but I've had T2X's running 80C for extended periods with no problems.

The air temp is 34C? Ouch! I think tomorrow's high is going to be -7C. That sounds a lot colder than Fahrenheit.

[rkawakami]

@abrogard:
CPU temp of 47c is fine. I generally see my T23 around 50c when in use. Unless you've done something with the CPU in your T21, it shouldn't be operating at 1.7Ghz (not Mhz). 700Mhz is about the right speed for the T21. If you plug in your type number (2647-xxx or 2648-xxx) at this page:

Support and Downloads

you can see what your system shipped with from the factory.

@dsigma6:
No, I haven't. I was merely saying that if the system is consistantly at that temperature, something needs to be checked. Either there's a process running in memory that's eating up all of the CPU cycles or the fan/thermal sensors in the laptop are not working properly. I too have had a system up around 80c (only for a couple of minutes) and did not have any problems with it. I WAS worried enough that I moved the laptop near an open window to keep it cool (it was transcoding a video clip).