Sun Microsystems SPARC classic X, Service Manual

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3-4 SPARCclassic/SPARCclassic X/SPARCstation LX Service Manual • November 1993
3.2 Normal Mode
Under Normal mode, when the system is turned on, control is sent to the Open Boot
PROM. Depending on the options set in the Open Boot PROM, for example if
autoboot is enabled (set to
true
), the operating system will load. Diagnostic testing
is not run.
3.3 Full Diagnostic Mode
Diagnostic mode, is the mode which tests the major hardware system board
components and, if the POST is successful, probes the installed SBus modules.
Diagnostic mode runs if one of these conditions is met:
■
You press and hold the Stop-d keys while you turn the on the power
■
You set the
diag-switch?
NVRAM parameter to
true
in the Open Boot PROM
■
You disconnect the keyboard and you set the
diag-switch?
NVRAM parameter
to
true
in the Open Boot PROM
Note – POST does not perform extensive testing on any system board component.
POST detects only major failures.
To view error messages returned by POST, connect a terminal to serial port A or use
a
tip
connection to another workstation.
If you do not connect a terminal to serial port A or use a
tip
connection, the screen
will be blank during the POST Diagnostic mode. In this case, use the keyboard LEDs
to display error conditions. See Section 3.7 “Status Lights (LEDs) and Indicators.”
3.4 Abbreviated Diagnostic Mode
A brief Power-On Self-Test (POST) is run if you disconnect the keyboard and you set
the
diag-switch?
NVRAM parameter to
false
in the Open Boot PROM. The brief
Power-On Self-Test is silent (no progressive test messages are printed out). If an
error or errors occur during the abbreviated Power-On Self-Test, all error messages
are displayed on the TTY or
tip
window.