Solving SCSI problemsNote: This information also applies to Serial Attached SCSI (SAS) problems.For any SCSI error message, one or more of the following devices might becausing the problem:v A failing SCSI device (adapter, drive, or controller)v An incorrect SCSI termination jumper settingv A missing or incorrectly installed SCSI terminatorv A defective SCSI terminatorv An incorrectly installed cablev A defective cableFor any SCSI error message, follow these suggested actions in the order in whichthey are listed until the problem is solved:1. Make sure that external SCSI devices are turned on before you turn on theserver.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 SCSItermination is set to automatic.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 problemsPower problems can be difficult to solve. For example, a short circuit can existanywhere on any of the power distribution buses. Usually, a short circuit will causethe power subsystem to shut down because of an overcurrent condition. Todiagnose a power problem, use the following general procedure: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, forexample, if a loose screw is causing a short circuit on a circuit board.3. Remove the adapters and disconnect the cables and power cords to all internaland external devices until the server is at the minimum configuration that isrequired for the server to start (see “Solving undetermined problems” on page84 for the minimum configuration).4. Reconnect all ac power cords and turn on the server. If the server startssuccessfully, replace the adapters and devices one at a time until the problem isisolated.If the server does not start from the minimum configuration, replace the componentsin the minimum configuration one at a time until the problem is isolated.82 System x3400 Types 7973, 7974, 7975, and 7976: Problem Determination and Service Guide
