Now solder the 6 transistors and the voltage regulator. Transistors are temperature sensitive and
too much heating time can destroy it. The use of pliers here pressing gently to body of the
transistor is a good way to dissipate the heat of the solder. You will need an extra hand (or tool).
Now solder de electrolitic capacitors to the rear part of the PCB. This capacitors are polarized. The
long leg of the capacitor should go to the "+" symbol of the PCB.
