Furuno GP-3500 - Manual (Page 178)

11. MAINTENANCE & TROUBLESHOOTING
11-8
11.6.3 Test pattern
The test pattern test checks the display for proper display of colors.
1. Press the [MENU] key to show the main menu.
2. Press the [0] key to show the SYSTEM SETUP menu.
3. Press the [6] key to show the TEST & MEMORY CLEAR menu.
4. Press the [3] key to show the test pattern screen (four-colored display).
5. Rotate the [ENTER] knob to change the pattern in the sequence shown
below.
Press KNOB TO CHANGE COLOR PATTERN.
PRESS MENU KEY TO FINISH THE TEST.
Black
Blue
Green
Red
White
White Red
Green Blue Black
Test pattern
6. Press the [MENU] key to finish the test.
7. Press the [MENU] key for several times to close the menu.