Fan problems on a laptop

[dmf]

The main cpu cooling fan works on post, and all the way up to the first flash of the Windows XP environment, at which point it cuts out and doesn't work anymore.

I tried using speedfan to force the speed but it is not adjustable on this machine.
does anyone have any other idea on what could cause this.

The machine is a NEC Lavie L 750ll/2

[barcode]

Could you double-check that model number? All I can find is the LL 750 x series...

* For those jumping in, this is a netbook-class laptop, described here.
Oh, great... They even made a "Hello Kitty" version... Which begs the question, "Can you commit seppuku with a netbook"?

Also, you state you're using XP, but this thing came with Vista. Are you sure you have the proper drivers for the mobo power functions?

Those questions withstanding, let's go over some major points about laptops (man, do I hate laptops...)

The two things that matter most with portable computers are cooling and battery life. Two of the most poorly designed features of portable computers happen to be cooling and battery life. You see, in order to cool off all that heat-generating hardware in that small space, you'd have to run the fans continually. Which sucks your battery dry in no time flat. If you don't run the fans to cool things down, and save the battery, then you can easily run into the CPU going into thermal shutdown (or throttling). There's plenty there for the designers to juggle with, but those are the main two.

Fortunately, there's a solution: run the fans when things get hot, and stop them when things cool down. It works like this:
- Power on EVERYTHING to make sure it's working (fan speed, etc.)
- Check system (POST)
- If power profile is to be set by the OS (Windows), leave alone, else use the BIOS settings <- Check!
- Boot OS, load power settings/controls, and do stuff

Now, it seems you're having the problem of the fan shutting down after POST and when the splash screen pops up (which is about where Windows would have loaded the power control drivers and settings). You fail to mention if Windows keeps running or not. If it still runs, gets really hot and blue-screens or slows down to a crawl (thermal throttle), then I'd guess that either the settings/driver is borked, or the thermistor (temp sensor) isn't working (dust bunnies, no contact with heatsink/cpu, etc.).
If Windows boots and runs, but the laptop doesn't get very hot, then I'd say it's doing exactly what it's supposed to: running the fan ONLY when needed.

I'm not sure about this model, but most laptops will allow you to get into the BIOS setup (F1, F2, F10, DEL, or maybe F12), and select "PC Health/Status". Once there, you should see a display of current temps, voltages, and FAN SPEED(s)! If the fan is running, you should see the RPM reading. If so, there's nothing wrong with the fan. If the fan stops or slows down, then look at the temp readings before the fan runs again, and if the fan starts up, look at them to see if they drop. If not, you have a plugged fan duct or heatsink fins (both common on laptops). All that's needed in this case would be to grab a can of compressed air and blow out the dust. If that doesn't work, some disassembly will be required to see what the problem is.

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Don't get me started on laptop jacks and plugs...

[dmf]

This machine is about 9 years old and made in Japan, with its original J/OS.
It's a great big P3 machine.

Unfortunately cooling settings are not available in BIOS.
Windows power settings are all at full power.
The ACPI drivers have all been reinstalled.
The ducts and fans are clear.
All cables are seated.

Using a WinPE live cd the fan doesn't run but using a Linux live cd it does.
Windows does continue to load normally, after a while you can burn your hand on the volume controls, and after a bit longer the machine will BSOD.

[barcode]

It's a great big P3 machine. Windows does continue to load normally, after a while you can burn your hand on the volume controls, and after a bit longer the machine will BSOD.

So... is it a laptop, or not?
Have you taken off and re-applied the CPU heatsink using fresh grease?

Unfortunately cooling settings are not available in BIOS.

Hmmm. If this is a laptop, it'd be darn odd that you wouldn't even have a status screen. Do you have the UBCD? That will allow you to boot and run a variety of utils to help pinpoint where the problem is.

Windows power settings are all at full power.

Errr. Does this mean you have it set to run full-blast, or that you have different "on AC / on BATT" profiles?

Using a WinPE live cd the fan doesn't run but using a Linux live cd it does.

Okay, this tells me the hardware is working. Windows may be misidentifying the hardware. It would make sense, as Windows had a big language barrier until about XP-SP2 or so. (Linux has no such barrier.)

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Denki Gishi