IBM 5150 Hardware Maintenance Manual page 91

The menu shown here should appear on your Display. You
may have recognizable but incorrect characters present on the
Display, producing an unintelligible message.
COLOR/GRAPHICS MONITOR ADAPTER TEST
0- DISPLAY ADAPTER TEST
1 - DISPLAY ATTRIBUTES
2 - CHARACTER SET
3 - 80X25 DISPLAY
4 - 40X25 DISPLAY
5 - 320X200 GRAPHICS
6 - 640X20D GRAPHICS
7 - LIGHT PEN TEST
8 - SCREEN PAGING
9 - EXIT TO MAIN MENU
10 - RUN ALL ABOVE TESTS
11 - VIDEO TEST
12 - SYNC TEST
ENTER NUMBER OF DESIRED ACTION
ARE RECOGNIZABLE BUT INCORRECT CHARACTERS
PRESENT ON THE DISPLAY?
YES
Replace your Color/Graphics Monitor Adapter. See
Section 3, "Removal/Replacement."
NO
500-20