The original fsu board was tied down only on the edges by that black plastic which was clipped by some small fins of the aluminium radiator .It did have a thermal paste i also used a paste .
The +12 i took from a main +12 and used a 2.5 amps fuse .
The transistor i think disipates about 50w to 80w of heat at low speeds that makes the heatsink to small to dissipate that heat and the airflow of the blower at that speed is too little.Its true the transistor is made for 250 degrees but lets be true they dont make like they used.