Epson 386SX - Manual (Page 213)

Light Pen Check
To check the function of a light pen connected to the color
graphics adapter card, select 8. This test checks that a light pen
connected to the color graphics adapter is performing
accurately. When you select this check, you see these prompts:
Confirm light pen is connected
correctly before starting the check.
Start the check ? (Y/N)
After you verify that the light pen is connected properly,
select
Y.
You see this prompt:
PLACE LIGHT PEN ON CENTER OF WHITE BLOCK
Touch the center of the white block on the screen with the
light pen. When the light pen is correctly positioned, the block
moves to another part of the screen for a second test. After
three successful tests, the check ends.
An error occurs if one of the following is true:
The light pen is not connected properly
The light pen is malfunctioning
You do not touch the square within 12 seconds.
Performing System Diagnostics C-21