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    AST RESEARCH, INC.          TECHNICAL BULLETIN # 1203                6-6-95

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    EXPANSION CHASSIS VOLTAGE FAIL INDICATIONS

    PROBLEM

    An incorrect integrated circuit may cause spurious voltage fail indications in
    the expansion chassis.

    CAUSE

    An integrated circuit did not meet specifications.

    SYSTEMS AFFECTED
    AST PART NUMBER AND DESCRIPTION

    501516-XXX     HW MOD MANHATTAN EXPANSION CABINET

    SOLUTION

    Replace the sensor board (part number 202644-002) with revision 04 or higher.

    CAUTION

    This modification should be performed by a qualified service technician.
    It is strongly recommended that this change be completed by an AST Authorized
    Service Center.  In no case will AST Research, Inc. be liable for damage to
    the system and its components, or loss of data caused by improper
    modification.

    PREREQUISITES

    A full backup of all data on the hard drive in the computer is strongly
    suggested.

    TIME REQUIRED

    30 minutes.

    STATUS VERIFICATION

    The revision level of the AST sensor board can be identified by observing the
    revision letter at the end of the nine-digit part number located on the solder
    side of the system board.

    TOOLS REQUIRED

    Standard computer tools.

    INSTALLATION PROCEDURE

    Removal and replacement of system "Field Replaceable Units" (FRUs) should only
    be performed according to the installation procedures approved and prescribed
    by AST Research, Inc.

    NOTE

    Warranty reimbursement for this change requires prior AST Research, Inc.
    approval.