Epson 486SX User Manual page 171

8. If you are running an application program, see if you need
to set up the program for the type of monitor and display
adapter you have. Also make sure you are using the
appropriate monitor and display adapter for your software.
9. If you installed an EGA or VGA display adapter card, or
another type of card that you want to be the primary
display adapter, you must set jumper JP4 to disable the
built-in VGA adapter or you will not see anything on the
screen. See "Changing the Jumper Settings" in Chapter 6
for instructions.
If you are using one or more display adapter cards, you
may need to change the setting of jumper JP6. This jumper
tells the computer whether you are using a color or
monochrome monitor and is set for color at the factory.
If JP6 is set incorrectly, you see a CRT error message.
If you are using two different types of video cards, set
jumper JP6 to the primary monitor type. See "Changing the
Jumper Settings" in Chapter 6 for instructions.
10. If you still have difficulty with your monitor, run the
appropriate diagnostic test for your adapter as described in
Appendix C. If the diagnostics program indicates an error,
contact the place where you bought the monitor.
Troubleshooting
B-16