The power supply of the router is broken. There is a transformer (silicon steel sheet), transformer, no load AC16V> rectifier and electrolytic capacitor 4700/
7809 the optimal pressure is 3~4V (input and output voltage difference), excess voltage into heat energy consumed, can add a resistor, as long as enough power, the bigger the better, resistance value in a few Ernest, this experiment can also be used to determine, only a few silicon diode string instead of resistance, according to each 0.6 volt drop to calculate the required number.
Do not change, you can also add a fan to the best conditions (exchange that kind of choice, DC can also, fan energy consumption is not), after all, long time high temperature will affect the power supply life.
19V AC rectified DC is 1.414 times the AC RMS, about 27V DC27V by 7809 step-down 9V, then the temperature must be high, if the front of the resistor, it will affect the size of the current
