Furuno SC-50S Operator's Manual page 55

Diagnostic test2
If the heading indication changes randomly when ship is at anchor or does not
change when the ship moves, run the test2 following the procedure below, with
the ship at anchor and satellite signal received.
Note: Heading is not output during the diagnostic test, and this is communicated
with an appropriate message. After completing the diagnostic test, turn
the power off and on to update heading data.
1. Press the MENU key to open the menu.
2. Choose SYS SETUP and then press the ENT key.
3. Choose TEST? and then press the ENT key.
4. Choose TEST2 and then press the ENT key.
5. Press ◄ to choose YES and then press the ENT key.
6. Press the ENT key twice. Rate and angle values are 0.0°. If the values
increase or decrease markedly (with ship at anchor), suspect rate sensor
trouble. Contact your dealer to request service.
7. Turn off the processor unit to quit the diagnostic test2.
3. MAINTENANCE, TROUBLESHOOTING
TEST1
TEST2
TEST3
Test menu options
TEST START?
(STOP: PWR OFF)
ARE YOU SURE?
NO
YES
Test start prompt
TEST2
YAW ROL
RATE
0.0° 0.0°
ANGLE 0.0° 0.0°
<STOP: PWR OFF>
TEST2 display
PIT
0.0°
0.0°
3-5