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    AST RESEARCH, INC.         TECHNICAL BULLETIN # 1213                6-14-95

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    DESKTOP SYSTEMS AND LITE-ON KEYBOARDS

    PROBLEM

    After booting to DOS, AST desktop systems may show several characters on
    the screen following the C:> prompt.  These characters appear to have been
    typed via the keyboard.  The characters can be deleted by pressing the
     key several times.

    The user may also be unable to log into a Novell Netware operating system
    because the keyboard buffer is full of hidden characters.

    CAUSE

    Incompatibility between the AST keyboard controller and the Lite-On
    keyboard BIOS.

    SYSTEMS AFFECTED

    Any AST systems using a Lite-On keyboard (AST part number 202851-001).

    SOLUTION

    The keyboard controller as well as the Lite-On keyboard BIOS have been
    upgraded with a revision of the system board or keyboard.

    The solution is to take the system to an AST Authorized Service Center for a
    system board replacement.  See part numbers and revision levels below.

    CAUTION

    This modification should be performed ONLY 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 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.

    PARTS REQUIRED
    AST PART NUMBER          DESCRIPTION                         REVISION

    202604-XXX              PCBA MBD PRM GX                      X16 or higher
    202612-XXX              PCBA MBD BRAVO MS 4-00               X16 or higher
    202620-XXX              PCBA MBD CHANNEL 1 SCSI SMT          X18 or higher
    202637-XXX              PCBA MBD PRM MX                      D
    202652-XXX              PCBA MBD P90                         X05 or higher
    202653-XXX              PCBA MBD P60                         X17 or higher
    202654-XXX              PCBA MBD ASYNCH                      X15 or higher
    202670-XXX              PCBA MBD DX-00                       X05 or higher
    202671-XXX              PCBA MBD P-0                         X14 or higher
    202694-XXX              PCBA MBD BMS-L 00                    X25 or higher
    202695-XXX              PCBA MBD CMT 4-00                    S
    202705-XXX              PCBA MBD BMS 4-00                    X10 or higher

    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 change,
    follow the setup and test procedures described in the AST User's Manual.

    NOTE

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

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