IBM 7985 Problem Determination And Service Manual

Chapter 3. DiagnosticsThis chapter describes the diagnostic tools that are available to help you solveproblems that might occur in the server.If you cannot locate and correct the problem using the information in this chapter,see Appendix A, “Getting help and technical assistance,” on page 185 for moreinformation.Diagnostic toolsThe following tools are available to help you diagnose and solve hardware-relatedproblems:v POST beep codes, error messages, and error logsThe power-on self-test (POST) generates beep codes and messages to indicatesuccessful test completion or the detection of a problem. See “POST” for moreinformation.v Troubleshooting tablesThese tables list problem symptoms and actions to correct the problems. See“Troubleshooting tables” on page 37.v Light path diagnosticsUse the light path diagnostics to diagnose system errors quickly. See “Light pathdiagnostics” on page 49 for more information.v Diagnostic programs, messages, and error codesThe diagnostic programs are the primary method of testing the majorcomponents of the server. The diagnostic programs are in read-only memory onthe server. See “Diagnostic programs, messages, and error codes” on page 55for more information.POSTWhen you turn on the server, it performs a series of tests to check the operation ofthe server components and some optional devices in the server. This series of testsis called the power-on self-test, or POST.If a power-on password is set, you must type the password and press Enter, whenprompted, for POST to run.If POST is completed without detecting any problems, a single beep sounds, andthe server startup is completed.If POST detects a problem, more than one beep might sound, or an error messageis displayed. See “POST beep codes” and “POST error codes” on page 30 for moreinformation.POST beep codesA beep code is a combination of short or long beeps or series of short beeps thatare separated by pauses. For example, a “1-2-3” beep code is one short beep, apause, two short beeps, a pause, and three short beeps. A beep code other thanone beep indicates that POST has detected a problem. To determine the meaningof a beep code, see “Beep code descriptions” on page 20. If no beep code sounds,see “No-beep symptoms” on page 27.© Copyright IBM Corp. 2006 19