Sun Microsystems SPARCstation 20, Service Manual

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27
C H A P T E R
4
Troubleshooting Procedures
This chapter describes how to troubleshoot possible problems and includes
suggested corrective actions.
TABLE 4-1
identifies system problems and corrective
actions.
TABLE 4-1
Troubleshooting Tips
System Problem Corrective Action
LED on front of system not lit Verify that the power switch is turned on and that the
power cord is connected to the system and an AC
receptacle. If the power switch is in the on position and
the power cord is connected, shut down the system and
verify that the LED cable is connected. If the LED cable is
connected, see “Power Supply Test” on page 29 and
“System Board Test” on page 31.
Disk drive fails to boot or does not respond Shut down the system. The SCSI controller or disk drive
may be defective. See “Disk Drive Errors” on page 33 and
“Power-On Does Not Succeed” on page 29; see also
Chapter 9.
Operating system does not recognize disk drive at
boot Shut down the system. Verify that every disk drive on the
SCSI bus is set to a different SCSI address. System
internal drives are automatically assigned SCSI addresses
as follows: 3 (bottom drive), 1 (top drive). See Chapter 9.”
No video output on monitor Verify that the power cord is connected to the monitor
and the monitor is turned on. Use a VOM to check
voltages. See “Video Output Failure” on page 28.