Chapter 4 137Intermittent ProblemsIntermittent system hang problems can be caused by a variety of reasons that have nothing to do with ahardware defect, such as: cosmic radiation, electrostatic discharge, or software errors. FRU replacementshould be considered only when a recurring problem exists.When analyzing an intermittent problem, do the following:1. Run the advanced diagnostic test for the system board in loop mode at least 10 times.2. If no error is detected, do not replace any FRU.3. If any error is detected, replace the FRU. Rerun the test to verify that there are no more errors.