Epson Equity 320SX PLUS - Manual (Page 196)

If you see one of these messages, make sure the diskette is
properly inserted in the drive. On a 51/4-inch diskette
drive, make sure the drive latch is closed. Try the
operation again. If the problem persists, try removing the
diskette and reinserting it. This may solve the problem if
the diskette was not seated properly in the drive.
If the error message still occurs, you may have a defective
diskette. Use the MS-DOS COPY command to copy the
files from the bad diskette to a new diskette. (See your
MS-DOS manuals for instructions.)
9. If you see no error messages but there is something
wrong with the data in a file, MS-DOS or an application
program may have updated the storage information on
the diskette incorrectly. This is probably the case if you
have one of these problems:
Part of a file is missing
A file includes parts of other files
An expected output file is missing.
Use CHKDSK to make the necessary repairs; see your
MS-DOS manuals for instructions.
Diskette Drive Problems
If you see an error message or have difficulty with a diskette
drive, check the following
1. If you are having problems with a new diskette drive that
your dealer installed for you, consult your dealer about
the problem.
2. If you installed the drive yourself, did you carefully
follow all the instructions in Chapter 7 of this manual?
Review the instructions and check all the cable
connections to make sure you have installed it correctly.
Troubleshooting c-11