About Cooling Fan
I have few repair friends that use cooling fan to solve electronic repair problem. In certain electronic equipment it will be difficult to get the exact transistor part and sometimes the new replacement part number would run hot and eventually burn the transistor again. It has nothing to do with the corresponding components that burn the transistor but it is the replacement transistor specification that do not match the original transistor spec and thus causing the new transistor to go shorted again. In order to solve the problem what they did was to install a small computer fan onto the circuit board and blow directly to the transistor and making the transistor runs cool.
First of course you have to find a near replacement of the transistor because if the spec is too way out, installing a fan would not solve the problem. You must also know at where you should tap the supply source to power up the fan. My repair friend would ask from the customer permission first before installing the fan and he will tell them that without the fan,the equipment would not last long. Surprisingly after installation of the fan the equipment worked perfectly good and no repeated repair! If you have no other choice then this could be a good solution to solve transistor heating problem.