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    AST RESEARCH, INC.          TECHNICAL BULLETIN # 1193               5-24-95

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    DESKTOP SYSTEMS HANG OPENING AND CLOSING APPLICATIONS IN WINDOWS

    PROBLEM

    Various desktop systems may hang when attempting to open or close applications
    in Windows.  The system may return error messages such as the following:

    Excel causes a General Protection Fault in module VGA.DRV at 0009:0D26.

    or

    EMM 386 has detected error # 06 in an application at memory address 00B8:0BC9.

    CAUSE

    There is an impedance mismatch (using certain vendors' parts) in the memory
    address lines to the SIMMS.

    SYSTEMS AFFECTED
    AST PART NUMBER AND DESCRIPTION

    501611-XXX          BRAVO MS 4-50S
    501612-XXX          BRAVO MS 4-66D
    501440-XXX          BRAVO MS 4-33S
    501432-XXX          PREMMIA MX 4-100
    501429-XXX          PREMMIA MX 4-66D
    501655-XXX          BRAVO MS-L 4-50D
    501644-XXX          ADVANTAGE! CMT 2-66D
    501443-XXX          BRAVO MS-L 4-100T

    SOLUTION

    Return the system to an AST Authorized Service Center for system board
    replacement.  Replace the system board with the corresponding AST part
    number:

    AST PART NUMBER

    202612-XXX
    202637-XXX
    202694-XXX
    202695-XXX
    202705-XXX

    For specific revision levels, contact your AST Authorized Service Center.

    NOTE

    To find out if the system has the above problem, inspect the system board at
    locations U11, U12, and U13.  If the board has an IC (integrated circuit) part
    number 74F245 from Texas Instruments or Signetics, the board should be
    replaced.  See part numbers above.

    CAUTION

    This modification should be performed ONLY by a qualified service
    technician.  It is strongly recommended that this replacement 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 system 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

    Refer to the system Hardware Maintenance Manual.

    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.

    Remove the system board according to procedures approved and prescribed
    by AST Research, Inc.

    CHECK-OUT PROCEDURE

    To verify proper operation of the system upon completion of this
    replacement, follow the setup and test procedures described in the AST User's
    Manual.

    NOTE

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

    The warranty on this system will become VOID if this replacement is
    completed by ANYONE other than an AST Authorized Service Center.