About Power-On Self-Test (POST) Diagnostics

The POST diagnostic code resides in flash PROM on the main logic board. It runs whenever the system is turned on or when a system reset is issued. POST tests the following system components:

• CPU modules

• Memory modules

• NVRAM

• Main logic board

POST reports its test results via LEDs located on the system keyboard and on the system front panel. See "Error Indications" for more information about LEDs and error messages.

POST displays detailed diagnostic and error messages on a local terminal, if one is attached to the system's serial port A. You can also choose to display POST output remotely on a Remote System Control (RSC) console.

The System Service Processor (SSP) runs its own POST diagnostics, separate from the main POST diagnostics. To view detailed diagnostic and error messages from SSP POST, you must attach a local terminal to the SSP (RSC) serial port prior to running SSP POST.

For more information about RSC and the System Service Processor, see "About Remote System Control (RSC)". For information about running POST, see "How to Use POST Diagnostics".