Mechanical Problems - NCR 7156 Service Manual

7156 Service Guide
Knife
MICR
Solenoid
Receipt
Feed
Motor

Mechanical Problems

Problem Possible Causes
Knife Does Not Operate
Bad knife home switch.
Printer not configured for
knife.
Knife motor switch not
plugged in.
Failure of the knife motor
or switch.
Note: When the knife test fails, a fault condition is triggered.
Problem Possible Causes
Printer Cycles But Does
Printhead cable not
Not Print
properly connected to the
PC board.
Impact Forms Comp
Printhead
Solenoid
What To Do
Check the knife sensor with an ohm meter at its harness and
test point.
Check the DIP switch settings. See Appendix B for the
settings.
Check connections to the PC board. See the section in
chapter 8 that applies to this unit's PC board.
Check the knife motor by testing the FETs on the PC board.
See "Field Effect Transistors (FETs)" in this chapter.
What To Do
Check the cable connection to the printhead and to the PC
board. See the section in chapter 8 that applies to this unit's
PC board.
Slip Feed Thermal
Motor Printhead
September 1998
Chapter 4: Troubleshooting
Carriage
Motor
47