My laptop is a Compaq C770TU which has been out of service for some time because of a faulty power supply. I tried to build a power supply temporarily due to delay in acquiring a new one. The plan was dropped because of design problems faced (a post s coming soon). so last day I go my power supply and switched it ON and did some stuff. Everything was going fine, then it switched off all of a sudden. The most likely cause would be overheating (thermal shutdown). All the computers today have an automatic thermal shutdown so that the processor will not get damaged. As expected the bottom side was red hot and being so curious I decided to open my favorite laptop to see what was wrong with the fan.
The problem being with the fan was kind of obvious. And off I went, grabbed a screw driver and kept taking things apart until nothing was left to fall out. The heat dissipation system is interesting. A large Copper bar is pressed on to the processor and this runs along the inside of the body to the air vent. There, a window with fins is attached to the copper bar (the fins are probably Aluminum but I am not sure). This is at the exit of the centrifugal blower. The pictures will help in easier understanding.
The blower and the fins fitted on the heat bar was full of dust and this prevented the blower from rotating. A large painting brush was used to remove the dust. The blower was connected to 5V supply and tested. The sound is really good to hear. especially when it is outside. Blower has a rating of 320mA @5V. Opening the laptop is pretty much easy if you have got the right tools. Most of the time a Philips screw river and a flat one would suffice. The flat one used to unclip the tabs. Only thing you need to care is not to break any of the clips and not to loose any screws you take off.