Epson 386SX - Manual (Page 210)

If the characters match the illustration, select Y. If you find a
problem with the characters on the screen, select N to display
the error message.
320x200 Graphics Mode Check
To check your 320x200 graphics mode, select 5. The screen
displays three colored squares-green, brown, and red-against
a cyan background. These four colors are Color Set 0. If they are
correct, select
Y.
The same pattern appears again; this time the squares are cyan,
white, and magenta, and the background is red. These colors are
called Color Set 1. If these are also correct, select
Y
to end the
test.
If any colors are displayed incorrectly, first check the
adjustment of your monitor, and make sure that both ends of
the cable are plugged in firmly. If a problem still exists, select
N
to display the error message.
C-18 Performing System Diagnostics