There comes a time when you want to upgrade your processor to something a bit faster. Once the case is opened you need to identify the processor. It will have a fan on top of it. It's best not to remove the fan but to get a new one designed for your new processor. The fan should suit the type of socket the processor sits in.
The processor sits in a ZIF socket. ZIF stands for Zero Insertion Force which
means that you don't have to push the component down hard. There is a small
lever at one side and raising this opens the socket making it free to insert
the component. The pins on the bottom of the component should match those on
the socket. One of the pins will be labelled in some way as pin 1. This should
match pin 1 on the socket. Because of the large number of pins a small dot is
often used or the corner may appear cut off. Once the component is resting properly
in the socket the lever may be closed by lowering it fully. The pins will fall
into their holes and be gripped to form an electrical connection.
The photopgraph (right) shows a typical processor seated in its socket. Various types of socket exist for various designs of processor so check yours before you start (the motherboard's manual may help here). The type of socket is known as Socket 7. This was common for a number of years. Note the metal lever towards the top of the picture in its lowered position. The processor has been covered with a substance known as thermal paste.
When a processor is operating it gets very hot. If it runs too hot it will
break down and stop working. The heat, therefore, needs carrying away (or dissipating).
This is achieved by placing a piece of metal on top known as a heatsink. In
a domestic sink once you pull the plug out all the water drains away down through
the plughole and down the drain. In a similar way a heatsink draws heat away
from the processor. The type of metal is chosen for its effectiveness in drawing
away heat and specially shaped to improve the effectiveness.
However, the bottom surface of the heatsink is not completely flat. A paste, grease or compound is therefore smeared over the joining surfaces to fill in any gaps. The substance is specially formulated for its heat transfer properties and enables a greater amount of heat to be carried away from the processor. There are various formulations by various companies. A small quantity is only usually required. As indicated there are various types of substance and it can be referred to as thermal paste, thermal grease or thermal compound. Radio Shack (Tandy) and Maplin should both be able to supply a version but using one of the web search engines should also reveal suppliers.
The processor sits amoungst many other components and in this instance is not
far away from the main RAM chips. Care should be taken when fitting not to disturb
anything. The actual location of the processor will depend on the design of
the motherboard. It may sit very near to the case and so there may not be much
room for your fingers to manoevure. It is often best to remove the board from
the case taking a note of where everything plugs in and so on to make things
easier.
For modern processors a heatsink is insufficient to cope with the amount of heat generated due to the large number of miniaturised parts that are squeezed onto the silicon chip. The solution is to fit a fan on top of the heatsink. The fan and heatsink usually come in a combined unit and are fairly cheap to buy.
The fan clips to the ZIF socket and by looking carefully at the photographs here you should be able to see how the fan clips on. The leg from the fan is silver and made of a flexible metal. There are small protrusions on the socket such that the side of the socket is not one smooth edge. Depending on the construction of the fan it will clip onto one or other protrusion. There is one clip each side of the socket. The fan holds the heatsink firmly in place by virtue of these clips.
A wire comes out of the fan to enable power to be fed to it. Some motherboards have special pins to attach the fan to so that it is powered from the motherboard. However, this is not reliable and as fans vary it is better to take the power directly from the main power supply. A sturdy plastic connector plugs into a corresponding connector. (One has pins the other has holes.) This is the same type of connector that internal peripherals (eg hard drive, floppy drive, CD ROM drive) connect with and there is usually one or more daisy chains of connectors. One of these should be spare where the old fan came from.
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