Forms Feeding Problems - NCR 7156 Service Manual

Chapter 4: Troubleshooting

Forms Feeding Problems

Problem Possible Causes
Forms Not Feeding Into
Failed paper feed motor.
Impact Printer
Slip stop in wrong
position.
Worn gears.
Failed PC board.
Problem Possible Causes
Forms Skew When
Paper path obstruction(s).
Feeding into Impact
Printer
Platen gap adjustment is
off.
Solenoid and form
compensation arm
functioning improperly.
Failed paper feed motor.
Problem Possible Causes
Forms Catch When
Paper path obstruction(s).
Feeding Into Impact
Printer
Ribbon cassette
improperly installed.
Platen gap adjustment is
off.
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What To Do
Use the FETs test to see if the paper feed motor has failed.
See "Field Effect Transistors (FETs)" in this chapter.
Check the slip stop. It should be up when the feed rolls are
open and down when the feed rolls are closed.
See if the bottom feed roll assembly gears are badly worn.
Replace the PC board. See "Removing the PC Board" in
chapter 9 and "Replacing the PC Board" in chapter 14.
What To Do
Remove obstruction(s) in the paper path.
Check and adjust the platen gap (.018 inches). See chapter 5.
Check if the solenoid and form compensation arm are
coming up when the printer operates.
Use the FETs test to check the paper feed motor.
Replace the paper feed motor. See chapter 19.
What To Do
Remove any obstruction in the paper path.
See if the ribbon cassette is properly installed.
Check and adjust the platen gap (.018 inches). See chapter 5.
September 1998
7156 Service Guide