Sun Microsystems Sun Blade 100, Service Manual

Page: 53 / 222

3-1
C H A P T E R
3
Power-On Self-Test
This chapter describes how to initiate power-on self-test (POST) diagnostics.
This chapter contains the following topics:
■
Section 3.1 “POST Overview” on page 3-1
■
Section 3.2 “Pre-POST Preparation” on page 3-1
■
Section 3.3 “Initializing POST” on page 3-3
■
Section 3.4 “Maximum and Minimum POST Levels” on page 3-4
■
Section 3.6 “Bypassing POST” on page 3-15
■
Section 3.7 “Resetting Variables to Default Settings” on page 3-15
■
Section 3.8 “Initializing Motherboard POST” on page 3-15
3.1 POST Overview
POST is useful in determining if a portion of the system has failed and should be
replaced. POST detects approximately 95 percent of system faults and is located in
the motherboard OpenBoot™ PROM. The setting of two NVRAM variables,
diag-
switch?
and
diag-level
, determines whether POST is executed and to what level
POST is executed (see Section 3.3 “Initializing POST” on page 3-3).
3.2 Pre-POST Preparation
Pre-POST preparation includes:
■
Setting up a terminal interface processor (TIP) connection to another workstation
or terminal to view POST progress and error messages. See Section 3.2.1 “Setting
Up a TIP Connection” on page 3-2.