640x200 graphic mode check, Screen paging check, C-16 – Epson 20 User Manual
Page 160
640x200 Graphics Mode Check
To
check your 640x200 graphics mode, press 6 then
Enter.
The
screen displays three patterned squares against a contrasting
background, as shown below.
640X200 GRAPHICS MODE CHECK
Is the display correct (Y/H)?
I
If the patterns on your screen are clear and distinct, press Y and then
Enter.
If any pattern is not clear, first check the adjustment of your
monitor, and then make sure that both ends of the cable are plugged
in firmly. If a problem still exists, press
N
and
Enter
to display the
error message.
Screen Paging Check
To check the screen paging of your monitor, press 7 and
Enter.
The
video RAM on the color graphics adapter is divided into eight
independent display pages. This test checks the eight pages by first
filling all eight with a number corresponding to the page, and then
displaying each page in turn. You see the following pattern for screen
0.
C-16
Performing System
Diagnostics