Epson LT-286 - Manual (Page 30)

The Power/Speed indicator above the keyboard lights up, and
after a few seconds the computer begins to perform an internal self
test. This is a diagnostic program the computer runs whenever you
turn it on. The power-on self test checks the RAM (random access
memory), keyboard, system board, and peripherals before the
computer begins normal operation.
For a complete description of the power-on diagnostics, see
Appendix C.
Adjusting Screen Contrast and Brightness
If you cannot see text on the screen clearly, use the switches on
the right side of the screen to adjust the screen’s contrast and
brightness. The switches are shown below:
The contrast switch determines how bright the characters appear
against the background. To increase the contrast, move the switch
up. To decrease it, move the switch down.
To make the backlighting brighter, move the brightness switch up.
To decrease the backlighting, move the switch down. To conserve
the battery’s charge when you’re running the computer on the
battery, do not make the screen brighter than necessary to read the
text clearly.
Setting Up Your System 1-17