Replacing The Sensors - Husqvarna Automower 420 Technical Manual

5.18 Replacing the sensors

5.18.1 Front loop sensors
The front loop sensors are mounted on the front
sensor circuit board. The sensors cannot be re-
placed separately. The entire front sensor circuit
board must be replaced as a unit.
1. Dismantle the body, see 5.2.1 Dismantling
the body on page 59.
2. Dismantle the chassis, see
5.2.2 Dismantling the chassis on page 59.
3. Disconnect the cable from the front
sensor circuit board. Note: Always pull the
connector and NOT the cable.
4. Unscrew the 2 screws (Torx 20) which
secure the holders for the front sensor
circuit boards.
5. Fit the new front sensor circuit board and
reconnect the cable.
6. Refit the chassis and body.
5.18.2 Rear loop sensors and tilt sensor
The rear loop sensors and tilt sensor are part of the
main circuit board. The sensors cannot be replaced
separately. The whole MCB must be replaced as
one unit, see 5.8 Replacing the MCB on page 65.
5.18.3 Lift sensors
The magnet on the collision column must be fitted
correctly if the lift sensors are to work. If this is not
the case, parts of the front collision column must be
replaced, see 5.23 Replacing front collision column/
lift sensor on page 76.
To replace the lift sensor circuit board:
1. Dismantle the body, see 5.2.1 Dismantling
the body on page 59.
2. Dismantle the chassis, see
5.2.2 Dismantling the chassis on page 59.
English - 72
5. REPAIR INSTRUCTIONS