IBM 88614RX Maintenance Manual - Page 37

Power checkout 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. A general procedure for troubleshooting power problems is as follows: 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 example, if there is a loose screw causing a short circuit on a circuit board. 3. Remove adapters and disconnect the cables and power connectors to all internal and external devices until the server is at the minimum configuration required to start the server (see "Minimum operating requirements" on page 136). 4. Reconnect all ac power cords and turn on the server. If the server starts up successfully, replace adapters and devices one at a time until the problem is isolated. If the server does not start up from the minimal configuration, replace FRUs of minimal configuration one at a time until the problem is isolated. To use this method, it is important to know the minimum configuration required for a system to start (see "Minimum operating requirements" on page 136). For specific problems, see "Power LED errors" on page 130. Ethernet controller troubleshooting The method of testing the Ethernet controller depends on which operating system is being used (see the Ethernet controller device driver readme file). If the problem remains after you check the operating system documentation, try the following: v Make sure that the Ethernet cable is installed correctly. The network cable must be securely attached at all connections. If the cable is attached but the problem remains, try a different cable. If you set the Ethernet controller to operate at 100 Mbps, you must use Category 5 cabling. If you directly connect two systems (without a hub), or if you are not using a hub with X ports, use a crossover cable. Note: To determine whether a hub has an X port, check the port label. If the label contains an X, the hub has an X port. v Determine whether the hub supports auto-negotiation. If it does not, try configuring the integrated Ethernet controller manually to match the speed and duplex mode of the hub. v Check the Ethernet controller LEDs on the server rear panel. These LEDs indicate whether a problem exists with the connector, cable, or hub. - The Ethernet Link Status LED is lit when the Ethernet controller receives a LINK pulse from the hub. If the LED is off, there might be a defective connector or cable or a problem with the hub. - The Ethernet transmit/receive activity LED is lit when the Ethernet controller sends or receives data over the Ethernet Network. If the Ethernet Transmit/Receive Activity light is off, make sure that the hub and network are operating and that the correct device drivers are loaded. Chapter 3. Diagnostics 27