Epson 20 - Manual (Page 154)

You can select the individual checks from this menu:
MONOCHROME DISPLAY ADAPTER AND CRT CHECK
MENU
1 - Monochrome adapter check
2 - Attribute check
3 - Character set check
4 - Video check
5 - Sync check
6 - Run all above checks
0 - Exit
Enter selection number:
If an error occurs during any of these tests, record the error code and
message, or print them out. Then contact your Epson dealer or
service center.
Monochrome Adapter Check
To check the monochrome adapter, press 1 and then Enter. The
computer checks the video RAM (display memory) on the display
adapter by writing certain data to memory, then reading it back and
comparing it to the written data. The computer also tests the video
enable signal of the display controller chip.
Attribute Check
To check the display attributes of the adapter card, press 2 and then
Enter. A series of messages appear showing examples of all the
possible display attributes (normal intensity, high intensity, blinking,
reverse, and underlining). Check the information that appears on
your screen, and then respond to the prompt:
Is the display correct (Y/N)?
Press Y and then Enter if the display is correct. If the display
attributes are not correct, adjust the brightness and contrast on your
monitor. If they are still incorrect, press
N and Enter.
C-IO Performing System Diagnostics