Sun Microsystems SPARCstation 4, Service Manual

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Chapter 3 Power-On Self-Test (POST) 3-9
3.7 Status Lights (LEDs) and Indicators
The LED at the front of the chassis lights when the system is operating normally.
FIGURE 3-5
shows the location of the system LED. Chapter 4 shows flow diagrams of
actions to take when the system LED is not lit.
FIGURE 3-5
Location of System Power LED
Section 3.1 “Power-On Self-Test (POST), describes the keyboard LED sequences
displayed at power up when the POST fails. If a failure occurs during the POST, the
keyboard displays a specific LED pattern. See
FIGURE 3-1
through
FIGURE 3-3
and
TABLE 3-1
. During normal system operation, the LEDs should not be interpreted as
diagnostic error indicators.
Following the system initialization, the operating system boots automatically, unless
the NVRAM configuration options specify not to do so.
Note –
The Caps Lock key LED on some U.S. keyboards, located just above the left-
hand Shift key, is not used as a POST failure indicator, but blinks on and off while
POST is running.
If the Caps Lock key fails to flash on and off after you have pressed and held the
Stop-d keys when you power on the system, the POST failed. See Section 4.2.2
“System Board Test,” for troubleshooting information.
System Front
System power LED