Power-On Self-Test (Post) - Sun Microsystems SPARCstation 4 Service Manual

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C H A P T E R

Power-On Self-Test (POST)

This chapter describes the Power-On Self-Test (POST) for Normal, Full, and
Abbreviated modes, available with your SPARCstation 4 and SPARC Xterminal 1
system.
Power-On Self-Test (POST)
Normal Mode
Full Diagnostic Mode
Abbreviated Diagnostic Mode
Tests the POST Runs
POST Error Messages
Status Lights (LEDs) and Indicators
The Power-On Self-Test (POST) diagnostics reside in the OpenBoot PROM located
on the system board. There are two POST modes: Normal and Diagnostic.
3.1 Power-On Self-Test (POST)
The Power-On Self-Test (POST) runs when you turn on the system unit power
switch and any of the following conditions apply:
diag-switch? NVRAM parameter is set to true.
Stop-d keys are held down when you turn on the power.
Keyboard is disconnected, and diag-switch? is set to false.
The POST comprises a sequence of tests designed to evaluate the major hardware
components of the main logic board in the short time before the OpenBoot PROM
firmware takes control. The POST does not perform extensive testing on any
component of the main logic board. Only major failures can be detected by the
POST.
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