Epson EL 486UC - Manual (Page 102)

If you replace the microprocessor, make sure the new processor
chip is installed correctly. Also make sure the jumpers are set
correctly and that pin 1 on the chip is connected with pin 1 on
the system board. See Chapter 4.
The Computer Does Not Respond
The computer locks up.
Wait a few moments; if your computer does not respond after a
reasonable length of time, press
Ctrl Alt Del. If that doesn’t
work, press the RESETbutton.
You may have installed memory using SIMMs that work at the
wrong speed. Install the correct SIMMs (see Chapter 4).
Your system may have over-heated. If you are using a DX or
DX2 processor, make sure you have an adequate heat sink
installed on the chip.
You reset the computer, but it still does not respond.
Try turning the computer off, wait 20 seconds, and turn it on
again.
Your computer suddenly stops operating.
You may have overloaded the power supply. See your option
card manual(s) for the power requirements for your option
card(s). Then check Appendix A to see if you have exceeded
the option slot power limits.
6-4 Troubleshooting