Solving Scsi Problems; Solving Power Problems - IBM 8863 - eServer xSeries 366 Service Manual

Solving SCSI problems

Note: This section also applies to Serial Attached SCSI (SAS) problems.
For any SCSI error message, one or more of the following devices might be
causing the problem:
v A failing SCSI device (adapter, drive, or controller)
v An incorrect SCSI termination jumper setting
v Duplicate SCSI IDs in the same SCSI chain
v A missing or incorrectly installed SCSI terminator
v A defective SCSI terminator
v An incorrectly installed cable
v A defective cable
For any SCSI error message, follow these suggested actions in the order in which
they are listed until the problem is solved:
1. Make sure that external SCSI devices are turned on before you turn on the
2. Make sure that the cables for all external SCSI devices are connected correctly.
3. If an external SCSI device is attached, make sure that the external SCSI
4. Make sure that the last device in each SCSI chain is terminated correctly.
5. Make sure that the SCSI devices are configured correctly.

Solving power problems

Power problems can be difficult to solve. For example, a short circuit can exist
anywhere on any of the power distribution buses. Usually, a short circuit will cause
the power subsystem to shut down because of an overcurrent condition. Use the
following general procedure for diagnosing a power problem:
1. Turn off the server and disconnect all ac power cords.
2. Check for loose cables in the power subsystem. Also check for short circuits, for
3. Remove the adapters and disconnect the cables and power cords to all internal
4. Reconnect all ac power cords and turn on the server. If the server starts
If the server does not start from the minimum configuration, replace the components
in the minimum configuration one at a time until the problem is isolated.
To use this method, you must know the minimum configuration that is required for
the server to start (see "Solving undetermined problems" on page 91).
server.
termination is set to automatic.
example, if a loose screw is causing a short circuit on a circuit board.
and external devices until the server is at the minimum configuration that is
required for the server to start (see "Minimum operating requirements" on page
91).
successfully, replace the adapters and devices one at a time until the problem is
isolated.
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Chapter 2. Diagnostics