Furuno FAR-2107 - Manual (Page 235)

6. MAINTENANCE, TROUBLESHOOTING
6-5
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, 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.