Husqvarna Automower 420 Technical Manual page 96

6.4.3 Blue flash
Most likely a break in the boundary wire. Measure
the resistance in the boundary wire using a multim-
eter. Disconnect all cables from the charging station
during measuring. The resistance value for a non-
faulty boundary wire should be between 0-20 Ohm.
• Value >20 Ohm: Indicates a break in the
boundary wire. Locate and repair the
break, see 6.5 Finding a break in the
boundary wire on page 97.
• Value <20 Ohm: Indicates that the
boundary wire is intact. Check instead
the connections to the charging station.
If the fault is not remedied, change the
circuit board in the charging station, see
5.25 Replacing the circuit board, charging
station on page 78.
6.4.4 Solid blue light
The boundary wire is probably too long. If the
boundary loop is longer than 800 meters, the
strength can start to drop even if it is still sufficient.
6.4.5 Red flash
Probably an interruption in the F or N loop in the
charging station's antenna plate.
Remove the charging station's cover and discon-
nect the connector from the circuit board. Measure
the resistance crosswise between the 4 pins in
the cabling's connector that has white cables con-
nected to it.
• Value for one of the cable pairs >20 Ohm:
Indicates a break in the antenna plate.
Replace the antenna plate.
• Value for both cable pairs < 20 Ohm:
Indicates that the antenna plate is intact.
Change charging station circuit board, see
5.25 Replacing the circuit board, charging
station on page 78.
6.4.6 Solid red light
Probably a fault in the circuit board in the charging
station. Change circuit board in charging station,
refer to 5.25 Replacing the circuit board, charging
station on page 78.
English - 96
6. TROUBLESHOOTING