Chapter 4. Troubleshooting; General; Common Causes Of Malfunctions; Testing - Printronix p300 Maintenance Manual

4–1. General
This chapter provides procedures for fault isolating printer malfunctions to field replaceable units. You
need a working knowledge of the User's Reference Manual in order to perform the fault isolation proce-
dures in this manual.
4–2. Common Causes of Malfunctions
When troubleshooting a malfunctioning printer, always begin with the simple and obvious. Do not fault
isolate complex systems until you have checked out the basics. Does the printer have uninterrupted pow-
er? Are electrical connections clean and tight? Are all circuit boards seated properly? Is the interface cable
connected properly? Problems associated with poor print quality are often cleared by simply correcting a
twisted ribbon, adjusting hammer alignment, platen gap, or belt tension — and sometimes by simply
cleaning the printer. Always verify basic alignments and adjustments first.
Improper printer operation can also result from electronic component failures, mechanical stress or fa-
tigue failures, or interface problems. Many problems can be corrected by replacing Printed Circuit Board
Assemblies (PCBAs), and this is the recommended approach when you encounter electronic problems.
Do not attempt field repairs on any PCBA — replace the entire board with an operational spare.
4–3. Testing
a. Self Test
The printer continuously monitors some of its own functions. When a problem develops, fault indications
appear on the control panel. For more information, refer to the User's Reference Manual.
b. Performance Tests
Performance tests evaluate printer operation, and are presented at the end of this chapter (paragraph 4–5).
These tests are also discussed in the User's Reference Manual.
4–4. Fault Isolation
Failures are divided into the categories listed in the Malfunction Symptom Index, Table 4–1. To fault iso-
late, locate your symptom in the table. The table will direct you to a flow chart that guides you through a
troubleshooting procedure.
NOTE: The troubleshooting flow charts in this manual do not take multiple fail-
ures into consideration.
P300/P600 Troubleshooting
CHAPTER 4
TROUBLESHOOTING
4–1