Epson Equity 286 PLUS - Manual (Page 214)

The controller displays one of the following messages when an
error occurs during a diagnostics procedure:
Address mark not found
Attachment failed to respond
Bad ECC on disk read
Bad sector flag detected
Controller has failed
Drive activity failed
ECC corrected data error
Requested sector not found
Reset failed
Seek operation failed
Write fault on selected drive
If you see one of these error messages, check the drive,
controller, cables, and power connectors. If you still get an error,
contact your dealer.
Floppy Disk Diagnostics
Floppy disk diagnostic tests may be destructive or non-
destructive. Destructive diagnostics destroy data on the diskette,
but non-destructive diagnostics do not. The following table lists
which tests are destructive and which are not.
Destructive tests
Format
Random R(ead)/W( rite)
Sequential R(ead)/W(rite)
Nondestructive tests
Drive speed
Drive change line
C-20 Performing System Diagnostics