5 Troubleshooting your system........................................................................ 145Safety first—for you and your system...............................................................................................145Troubleshooting system startup failure........................................................................................... 145Troubleshooting external connections............................................................................................145Troubleshooting the video subsystem............................................................................................. 145Troubleshooting a USB device......................................................................................................... 145Troubleshooting iDRAC Direct (USB XML configuration)............................................................... 146Troubleshooting iDRAC Direct (Laptop connection)...................................................................... 147Troubleshooting a serial I/O device................................................................................................. 147Troubleshooting an NIC....................................................................................................................147Troubleshooting a wet system......................................................................................................... 148Troubleshooting a damaged system................................................................................................149Troubleshooting the system battery................................................................................................ 149Troubleshooting power supply units............................................................................................... 150Troubleshooting power source problems................................................................................. 150Power supply unit problems....................................................................................................... 150Troubleshooting cooling problems.................................................................................................. 151Troubleshooting cooling fans........................................................................................................... 151Troubleshooting system memory.................................................................................................... 152Troubleshooting an internal USB key............................................................................................... 153Troubleshooting an SD card............................................................................................................. 153Troubleshooting an optical drive..................................................................................................... 154Troubleshooting a tape backup unit................................................................................................ 154Troubleshooting a hard drive............................................................................................................155Troubleshooting a storage controller.............................................................................................. 156Troubleshooting expansion cards.................................................................................................... 156Troubleshooting processors............................................................................................................. 157System messages.............................................................................................................................. 158Warning messages...................................................................................................................... 158Diagnostic messages...................................................................................................................158Alert messages.............................................................................................................................1586 Using system diagnostics................................................................................159Dell Embedded System Diagnostics.................................................................................................159When to use the Embedded System Diagnostics...................................................................... 159Running the Embedded System Diagnostics from Boot Manager............................................159Running the Embedded System Diagnostics from the Dell Lifecycle Controller.....................159System diagnostics controls....................................................................................................... 1607 Jumpers and connectors.................................................................................161System board jumper settings...........................................................................................................1617