Furuno FELCOM501 Operator's Manual page 170

7. MAINTENANCE AND TROUBLESHOOTING
4. Press
The ROM/RAM test starts.
Test in progress
"– –" means that the test is processing.
The results appear as "OK" for normal status, "NG" for abnormal status.
5. Press the Enter key to go to the LCD test.
6. Press the Enter key to start the LCD test.
Each press of the Enter key changes the LCD pattern in the sequence shown be-
low.
White
RGB gradation
7-6
to select [OK].
Black
Checker board
(Blcke/White)
Test results
Red
Checker board
(White/Blcke)
Green
Blue