IBM 3270 Maintenance Manual page 313

You have gone through the PICs without solving
your problem. The following steps should help
you find additional audio or visual symptoms.
1.
Check the entire system for loose or damaged
connectors.
2. Return to page 3-5-1 and review "Start."
3. Select "LOG UTILITIES" in the System
Checkout menu, start an error log, and select
"RUN TESTS MULTIPLE TIMES." This will
allow you to operate the system thoroughly
and identify the symptom. Then go to page
3-5-1, "Start," or the appropriate PIC for the
symptom you received.
If you have followed these procedures and still
have an unsolved problem, request technical
assistance.
3-1700-26 Maintenance Information