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    AST RESEARCH, INC.         TECHNICAL BULLETIN # 1154                4-24-95

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    				INTERPRETATION OF MANHATTAN SMP LEDS

    This is an informational bulletin.

    The supplemental information included in this bulletin is intended to assist
    technicians supporting the AST Manhattan SMP.

    The Manhattan SMP includes a number of hardware-based diagnostic tools,
    including the LEDs on each of the IOSM, Processor and Memory boards in the
    system.  These LEDs provide information about the status of the board, and if
    a failure occurred, may give basic failure information as well.
    The information below will help interpret the meanings of the LEDs.

    INTERPRETATION

    There are three types of LEDs on the Manhattan SMP's system bus boards
    (IOSM, Processor and Memory).  The LEDs may be lit as red, green, or
    yellow.

    RED LEDS

    Red LEDs indicate an error condition.  The error may be either a fatal or a
    non-fatal error.

    The red LEDs will indicate one of the following:

    1. The failure of a system bus board: IOSM, Processor, or Memory, indicated
    by patterns of LEDs on the board.  See AST Manhattan SMP Installation and
    Maintenance Manual (001169-001, Table 7-4 or 001725-001. Table 13-4) for a
    description of each LED combination.

    2. The failure of an EISA bus adapter.  The individual board is not identified.

    3. The failure of a software driver that is bad or has been incorrectly
    configured.  This condition may result, for example, in the system attempting
    to access memory addresses when no physical memory is installed at the
    addressed location.

    If the error was non-fatal, the system does not crash.  The error will be
    reported via one of the Manhattan SMP's Operating System utilities: MP31.NLM
    for NetWare or EFS for SCO UNIX.  Only one occurrence of an error is reported
    every 30 minutes.  If multiple errors are reported consistently, the cause of
    the problem should be investigated and corrected.  Use standard hardware and
    software troubleshooting techniques to isolate the hardware or software
    component responsible for the error.

    YELLOW LEDS

    Yellow LEDs indicate that a single bit memory error occurred and has been
    corrected.

    The yellow LEDs will indicate a single occurrence of a single bit memory error
    on each memory board.

    The memory board corrects the single bit memory errors, and the error is
    reported via one of the Manhattan SMP's Operating System utilities:
    MP31.NLM for NetWare or EFS for SCO UNIX.  The utility will indicate on
    which memory board the single bit memory error occurred.  Only one
    occurrence of an error is reported every 30 minutes. If multiple errors are
    reported consistently, the cause of the problem should be investigated and
    corrected. Exercise the indicated memory board by running Advanced System
    Diagnostics, which will isolate the SIMM bank that needs to be replaced.

    GREEN LEDS

    Green LEDs indicate that the board is in the Ready/Idle state.  The LEDs also
    indicate:

    1. An active/enabled board.  The LED will be on, flashing, or very dim when
       the board is active.

    2. An idle board.  The LED stays ON solid and does not flash.  This condition
       indicates that the board passed POST testing, and was enabled, but is not
       currently in use by the system.

    3. A disabled board.  The LED is OFF.  This condition indicates that the board
       failed POST testing and was disabled.  A disabled board will not be tested
       or detected by Advanced System Diagnostics.

    TROUBLESHOOTING TECHNIQUE

    If a system crashes, do not turn the system power OFF.  Open the side door and
    identify the status of the LEDs.  Check to see which LEDs are ON or OFF, and
    check the color of each LED.

    If red LEDs are ON, see the Manhattan SMP Installation and Maintenance
    Manual for more information and take any required corrective action.

    If any green LEDs are OFF, the board was disabled before the system crashed
    or the board was active when the system crashed.  In either case, replace any
    board on which the green LED is OFF.