Epson TM-U200 Operator's Manual page 41

The ERROR light is off, but nothing is printed.
Try to run the self test to check that the printer works properly. See
the self test instructions in Chapter 1 to run the self test. If the self
test does not work, contact your dealer or a qualified service
person.
If the self test works properly, check the following:
1. Check the connection at both ends of the interface cable
between the printer and the computer. Also make sure this
cable meets the specifications for both the printer and the
computer.
2. The data transmission settings may be different between the
printer and computer. Make sure the printer's DIP switch
settings for data transmission are the same as the computer's.
You can print the printer's interface settings using the self test.
If the printer still does not print, contact your dealer or a qualified
service person.
The printer sounds like it is printing, but nothing is printed.
The ribbon cassette may not be installed properly. See the
instructions in Chapter 1.
The ribbon may be worn out. Replace the ribbon cassette as
described in Chapter 1.
If the printer still does not print, contact your dealer or a qualified
service person.
The printout is faint.
The ribbon may be worn out. Replace the ribbon cassette as
described in Chapter 1.
3-2 Troubleshooting