The internal structure of the servo
On the bottom of the servo casing, you can see
the heads of the four long screws holding the
base in place. If you remove these screws, you
can separate the three sections of the casing.
With the base of the casing removed, you
can see the circuit board that translates the
signals coming from the RC receiver into
commands that operate the mechanism of the
servo. Removing the top of the case will
Right: The three sections
that make up the casing of a
servo are held together by
four Phillips screws. By
removing the screws, you
can take off the casing’s base
to reveal the circuit board.
Above: The bottom of a
servo, with the casing
removed. The circuit board
houses an electric motor
(arrowed), which drives
the servo mechanism.
Below: The inside of the
top of the servo casing.
Left: Removing the top of
the servo casing reveals
the gears that transfer
motion from the motor to
the servo horn.
expose the gears, which transmit the motion
of the motor to the servo horn. The gears also
slow down the motion, thereby increasing the
torque it applies to the servo horn so that the
linkages can exert the force required to move
the steering, throttle and brake mechanisms.
The gears, which are toothed plastic wheels,
can be removed from the pins that they are
mounted on. The primary gear, which turns all
the others, is fixed to the shaft of the motor.
Right: The mounting pins
with the gears removed.
119
120
