INTIP03

Use this procedure to isolate problems with external noise on AC voltage lines.

DANGER
When working on or around the system, observe the following precautions:
Electrical voltage and current from power, telephone, and communication cables are hazardous. To avoid a shock hazard:
  • Connect power to this unit only with the IBM provided power cord. Do not use the IBM provided power cord for any other product.
  • Do not open or service any power supply assembly.
  • Do not connect or disconnect any cables or perform installation, maintenance, or reconfiguration of this product during an electrical storm.
  • The product might be equipped with multiple power cords. To remove all hazardous voltages, disconnect all power cords.
  • Connect all power cords to a properly wired and grounded electrical outlet. Ensure that the outlet supplies proper voltage and phase rotation according to the system rating plate.
  • Connect any equipment that will be attached to this product to properly wired outlets.
  • When possible, use one hand only to connect or disconnect signal cables.
  • Never turn on any equipment when there is evidence of fire, water, or structural damage.
  • Disconnect the attached power cords, telecommunications systems, networks, and modems before you open the device covers, unless instructed otherwise in the installation and configuration procedures.
  • Connect and disconnect cables as described in the following procedures when installing, moving, or opening covers on this product or attached devices.
    To Disconnect:
    1. Turn off everything (unless instructed otherwise).
    2. Remove the power cords from the outlets.
    3. Remove the signal cables from the connectors.
    4. Remove all cables from the devices
    To Connect:
    1. Turn off everything (unless instructed otherwise).
    2. Attach all cables to the devices.
    3. Attach the signal cables to the connectors.
    4. Attach the power cords to the outlets.
    5. Turn on the devices.

    (D005)

Electrical noise on incoming ac voltage lines can cause various system failures. The most common source of electrical noise is lightning.
  1. Ask the customer if an electrical storm was occurring at the time of the failure to determine if lightning could have caused the failure.

    Could lightning have caused the failure?

    • No: Go to step 3.
    • Yes: Continue with the next step.
  2. Determine if lightning protection devices are installed on the incoming ac voltage lines where they enter the building. There must be a dedicated ground wire from the lightning protection devices to earth ground.

    Are lightning protection devices installed?

    • Yes: Continue with the next step.
    • No: Lightning may have caused the intermittent problem. Recommend that the customer install lightning protection devices to prevent this problem from recurring. This ends the procedure.
  3. Have an installation planning representative perform the following:
    1. Connect a recording ac voltage monitor to the incoming ac voltage lines of the units that contain the failing devices with reference to ground.
    2. Set the voltage monitor to start recording at a voltage slightly higher than the normal incoming ac voltage.

    Does the system fail again with the same symptoms?

    • No: This ends the procedure.
    • Yes: Continue with the next step.
  4. Look at the recording and see if the voltage monitor recorded any noise when the failure occurred. Did the monitor record any noise when the failure occurred?
    • Yes: Review with the customer what was happening external to the system when the failure occurred. This may help you to determine the source of the noise. Discuss with the customer what to do to remove the noise or to prevent it from affecting the server. This ends the procedure.
    • No: Perform the next intermittent isolation procedure listed in the Isolation procedure column. This ends the procedure.