NCR 7156, Руководство по обслуживанию, Страница: 63 / 206

7156 Service Guide Chapter 4: Troubleshooting
September 1998 49
Problem Possible Causes What To Do
Carriage Homes
Incorrectly
Jammed carriage. Turn off the power to the printer and place the feed rolls in
the down position. Move the carriage to see if the carriage
moves freely.
If the carriage does not move freely perform preventive
maintenance dusting.
Paper jam. Clear any paper jams.
Jammed ribbon cassette. See if the ribbon cassette is jammed.
Dirty carriage rack. Wipe the carriage rack clean. See chapter 12.
Dirty L-bracket. Check the L-bracket and wipe clean. See chapter 12.
Dirty or worn drive plate
pulley gears. Check and clean the pulley gears (on the drive plate). See
chapter 13.
Improperly positioned
drive plate assembly. Make sure the drive plate is correctly positioned. If the
grommet pins are not in place, the drive plate can come too
far forward and bind movement in the carriage. See
chapter 13.
Bad home sensor and/or
home flag. See if the home sensor and/or the home flag is broken or
dirty.
If any part of the home sensor is broken replace the entire
sensor assembly. See chapter 13.
Check the home sensor with an ohm meter at its harness
and test point (TSTRP).
Improperly positioned
timing belt. Check that the timing belt is properly installed on the drive
plate pulleys and carriage assembly. See chapter 13.
Platen gap incorrectly
adjusted. Check and adjust the platen gap (.018 inches.). See
chapter 5.
Solenoid not in the down
position. Check that the solenoid is operating and replace it if
necessary. See chapter 18.
Note: Home position for the carriage is slightly to the left of center.