Chapter 2. 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 159 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 43.v Light path diagnosticsUse the light path diagnostics to diagnose system errors quickly. See “Light pathdiagnostics” on page 56 for more information.v Diagnostic programs, messages, and error messagesThe diagnostic programs, which are stored in upgradeable read-only memory(ROM) on the system board, are the primary method of testing the majorcomponents of the server. See “Diagnostic programs, messages, and errorcodes” on page 61 for 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 detects a problem, one or more beeps might sound, or an error messageis displayed. See “POST beep codes” and “POST error codes” on page 28 for moreinformation.POST beep codesA beep code is a combination of short or long beeps or a series of short beeps thatare separated by pauses. For example, a “1-2-3” beep code is one short beep, apause, two short beeps, and pause, and three short beeps. A beep code indicatesthat POST has detected a problem.A single problem might cause more than one error message. When this occurs,correct the cause of the first error message. The other error messages usually willnot occur the next time POST runs.© Copyright IBM Corp. 2006 19
