Epson EL 486UC - Manual (Page 101)

The Computer Will Not Start
The power light is on, but the computer does not start
Replace your main operating system diskette and turn on the
computer again.
The computer does not start and the powerlight is not lit
Make sure the power cord is securely connected to both the AC
inlet on the back panel and an electrical outlet.
The power cord is securely connected, but the computer
still does not start.
Check the electrical outlet for power. Turn off your computer
and unplug the power cord. Plug a lamp into the outlet and
turn it on.
You installed or removed system components, and now
your computer does not start.
Check to make sure you have reconnected all the internal and
external cables correctly.
You may have installed option cards that exceed the system’s
power requirements. Check the power requirements in
Appendix A.
You may have installed a SIMM incorrectly. If the system
doesn’t find memory, nothing happens. Check that your
SIMM(s) are securely installed in their sockets.
Troubleshooting 6-3