Furuno BB FAR28x7 - Manual (Page 238)

6. MAINTENANCE, TROUBLESHOOTING
6-4
6.4 Replacement of Battery on GC Board
The battery installed on the GC (GyroCompass) Board inside the processor unit
preserves gyro data when the power is turned off. The life of the battery is about
five years. When the battery voltage is low, NG appears at the diagnostic test for
the GC Board. When this occurs, contact your dealer for replacement.
Battery on GC Board
Battery type Code number
GC board CR 1/2 8.L 000-103-769
6.5 Trackball Maintenance
If the cursor skips or moves abnormally, clean the trackball as below.
1. Turn the retaining ring counterclockwise 45° to unlock it.
Retaining Ring
2. Remove the retaining ring and ball.
3. Clean the ball with a soft, lint-free cloth, and then blow carefully into the
ball-cage to dislodge dust and lint.
4. Look for a build-up of dirt on the metal rollers. If dirty, clean the rollers using a
cotton swab moistened lightly with isopropyl-rubbing alcohol.
5. Make sure that fluff from the swab is not left on the rollers.
6. Replace the ball and retaining ring. Be sure the retaining ring is not inserted
reversely.