I think knowledge is open source. So here is my knowledge about the Sony TX3XP/L Notebook
Other stuff I did: GPS | SonyEriccson K750i | Ericsson t39m | Strategic Design (german) | Frei Otto (german) | goldfish
Problem
Many people criticize that the TX fan spins up too often on the otherwise near perfect notebook. In normal operation mode, even with the powersettings set to reduced power, the fan comes up 2-3 times every minute and spins for a few seconds. Obviously this blows out hot air from the inside and sucks cool air back in. There should be another way to accomplish this, I thought.
Solution
As you can see on this image the fan is not mounted on the cpu heat sink, but only blows out of the case. Nearly at the same place, however, there is the Compact Flash Slot, that is normally covered by a plastic flap. One should only need to blow in there to get the same effect as the internal fan blowing out.
Prototype Setup
A small silent external fan, connected to the usb port, blows into the direction of the CF-slot. For the test I opened the small flap with a pen, later one could use the small plastic part that covers the CF-slot when the TX is delivered new to keep it open. The plastic part is not necessary under normal conditions, because the small flap protects the CF-slot good enough.
Effect
It really works. While under normal typing operation the notebook had around 57/58 °C the temperature drops to 52/53 °C nearly immediately after connecting the external fan. The internal never started again from that point! Ok, I must admit it's winter, currently, and the room temperature is around 20 °C. I guess in summer this will not work as good.
Disclaimer: Of course this solution is not recommended and not tested over a longer period of time. I am not liable for any damage you do to your notebook by using the above solution!