This photo below is of the Thermal unit on my Toshiba Notebook when I pulled it apart to replace the fan because it was extremely noisy.
What is shown is only half the dust as the rest fell out when I moved the the fan away from the thermal unit. The Thermal unit on notebook is used to move the heat from the CPU to the side of the notebook so the fan can blow the heat out the side. It would appear to be a big design problem as the fins of the thermal unit are so close together that the dust builds up on them. It would seem to be more prevalent in a humid environment where the movement of air over the thermal unit can cause a small amount of moisture to form so allowing the dust to stick to the fins of the thermal unit and so build up.
Marg has an exact same model of Toshiba and yesterday we notice it was getting quite hot. It is not possible to see this build up of dust from the outside of the notebook because the fins of the thermal unit are so close together. It is also extremely difficult to remove such dust without completely dismantling the notebook. I was able to remove very small pieces of dust by blowing over the thermal unit and vacuuming it out through the fan inlet vent. I have thought of trying to break up the dust block by pushing it back towards the fan with thin strips or plastic. I have been told you can purchase can of compressed air at electronic stores, but I dont no how I would get the blast of compressed air in past the termal unit.
Any suggestions would be greatly appreciated
Other people with notebook computers should be aware that there is a big possibility of dust build up in notebook computers to the extent that they can overheat