Active cooling needs power supply. In "upper center" of the board is a 12V DC power connector (CNP2) that could easily be used. But this is always on - even in standby. I don't want to have the fan rotating also in standby - makes noise, wastes energy and reduces FAN lifetime

without deep circuit reverse engineering two more 5volts DC power sources are obvious: USB connector and the PC Card slot. Both are supposed only to be powered if TV is switched on. Their use presumes that current draw of the FAN will not influence their operation.

As I do not need PC Card slot (Pay TV, etc.) but USB I chose the PC Card pins 17&34 (VCC&GND) to get 5 volts (pls. verify correct pin selection with multimeter!)