Epson 386/25 - Manual (Page 263)

If the jumper is set incorrectly, you will see one of these
messages:
401 CRT error
501 CRT error.
If you are using two different types of video cards, set jumper
JP12 to the primary monitor type. You may also need to
change the setting later if you change the type of monitor
you are using. See “Changing the Jumper Settings” in
Chapter 5 for instructions.
10. If you are still having difficulty with your monitor, run
either the Monochrome Display Adapter and CRT check
or the Color Graphics Adapter and CRT check, described in
Appendix E. If the diagnostics program indicates an error,
contact the place where you bought the monitor.
Diskette Problems
You may see the following message if you are having trouble
with a diskette or your diskette drive:
601 Diskette error
If you see this message or have trouble accessing data on a
diskette, try the following steps:
1. Did you turn down the diskette drive latch on a 5¼-inch
drive to secure the diskette in the drive? See Chapter 3 for
more information.
2. You may have inserted the diskette upside-down or it may
not be inserted all the way. Remove the diskette from the
drive and reinsert it with the label facing up. Be sure to turn
down the diskette drive latch. (See Chapter 3 for detailed
instructions on inserting and removing diskettes.)
Troubleshooting D-15