Instruction manual

3–29Troubleshooting
Symptoms Not Indicated by Fault Messages
Use standard fault–isolation techniques to troubleshoot malfunctions not
indicated by fault messages. These techniques are summarized below:
1. Ask the operator to describe the problem.
2. Verify the fault by running diagnostic tests or replicating conditions
reported by the user.
3. Look for a match in the “Symptoms Not Indicated by Fault Messages
Troubleshooting Table” on page 3–30, and follow the instructions given.
4. Locate the malfunction using the half–split method:
a. Start at a general level and work down to details.
b. Isolate faults to half the remaining system at a time, until the final
half is a field–replaceable part or assembly. (Troubleshooting aids
are listed on page 3–2.)
5. Replace the defective part or assembly.
IMPORTANT
DO NOT attempt field repairs of electronic components or assemblies.
Replace a malfunctioning electronic assembly with an operational spare.
Most electronic problems are corrected by replacing the printed circuit
board assembly, sensor, or cable that causes the fault indication. The
same is true of failures traced to the hammer bank: replace the entire
shuttle frame assembly. It is not field repairable.
6. Test printer operation after every corrective action.
7. Stop troubleshooting and return the printer to normal operation when the
reported symptoms disappear.