Furuno GP-3500 - Manual (Page 173)

11. MAINTENANCE & TROUBLESHOOTING
11-3
11.4 Trackball Maintenance
If the cursor skips or moves abnormally, you may need to clean the trackball.
1. Turn the retainer ring counterclockwise 45° to unlock it.
Retainer ring
Ball
Display unit
2. Remove the retainer 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 retainer ring.
Note:
Trackball maintenance parts are available as below.
Part Type Code No.
Retainer ring and ball MU3721 000-144-645