Furuno 520 - Manual (Page 68)

6. MAINTENANCE & TROUBLESHOOTING
6-8
Error messages (con’t)
INPUT VOLTAGE IS OVER
(UNDER) LIMIT
The input power source fluctuated
beyond tolerance.
Check ship’s mains.
MAGNETIC SENSOR ERROR
RATE SENSOR ERROR
The heading data from the heading
sensor was wrong.
Check the heading sensor.
NO CALIBRATION Calibration not yet executed.
Ask your dealer to do the
calibration.