Sun Microsystems Enterprise 250 Owner's Manual page 277

logic board. If replacing both the disk drive and the main logic board does not
correct the problem, replace the associated UltraSCSI data cable and UltraSCSI
backplane.
SCSI Controller Failures
To check whether the main logic board SCSI controllers are defective, test the drive
response to the probe-scsi command. To test additional SCSI host adapters added
to the system, use the probe-scsi-all command. You can use the OBP printenv
command to display the OpenBoot PROM configuration variables stored in the
system NVRAM. The display includes the current values for these variables as well
as the default values. See "OBP printenv Command" on page 250 for more
information.
1. At the ok prompt, enter:
ok probe-scsi
If a message is displayed for each installed disk, the system SCSI controllers have
successfully probed the devices. This indicates that the main logic board is working
correctly.
2. If a disk doesn't respond:
a. Make sure that each SCSI device on the SCSI bus has a unique SCSI target ID.
See "About the SCSI Removable Media Bays and the External SCSI Port" on
page 67 for more information on SCSI IDs.
b. Verify that all SCSI cables and the SCSI terminator are connected securely.
c. Check that there are no bent pins on the SCSI cables.
3. If the problem persists, replace the unresponsive drive.
4. If the problem remains after replacing the drive, replace the main logic board.
5. If the problem persists, replace the associated SCSI cable and backplane.
Power Supply Failure
If there is a problem with a power supply, POST lights the general fault indicator
( ) and the power supply fault indicator (
than one power supply, then you can use the LEDs located on the power supplies
) on the front panel. If you have more
Chapter 11 Diagnostics and Troubleshooting 259