Furuno FM-4800 Operator's Manual page 101

Phenomena
is selected.
The icon or
appears on
the home screen.
Your position is
not displayed.
The radio unit
displays "PLL
UNLOCK".
If the above solutions cannot fix your problems, or you may have some other queries,
please contact us or your local dealer for more technical support.
Probable
Cause
Too high or too
low power
supply voltage
Accessory
cable
Setting of the
GNSS receiver
The phase lock
loop not
working
Solution
Confirm that the connected power
supply voltage is within 10.8 to 15.6
VDC.
Check the NMEA2000 or NMEA0183
cable connection.
Choose the proper information to
check:

If the NMEA2000 or NMEA0183
cable is connected, make sure
that the output of the cable is valid.

If the NMEA2000 or NMEA0183
cable is not connected, make sure
that the internal GNSS module is
enabled and nothing blocks the
top of the radio unit.
Restart the radio. If the problem is not
fixed, please consult your dealer.
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