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    AST RESEARCH, INC.          TECHNICAL BULLETIN # 1145               4-18-95

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    				TERMINATION NOT DISABLED ON QUANTUM 1080S

    PROBLEM

    Systems using the Quantum 1080S SCSI Hard Disk may experience disk failures
    or other intermittent problems related to termination.  These problems could
    include disks dropping off-line, shadowed drives, and SCSI bus time-out
    errors, especially when the SCSI sub-system is under heavy use.

    CAUSE

    Although the TE (Termination Enabled) jumper (J13) is removed, the bus lines
    are still terminated through an AC termination circuit.  Due to this
    condition, the hard disk remains terminated when the jumper has been removed.
    The resistors located next to the TE jumper must be removed to ensure proper
    operation.

    SYSTEMS AFFECTED
    AST PART NUMBER AND DESCRIPTION                        REVISION
    501530-XXX          Manhattan G560                     Model 1003
    501500-XXX          Manhattan V5090                    Model 1003
    501502-XXX          Manhattan P5090                    Models 1003E & 2003AE
    500872-009          HDISK 1.0GB FastSCSI w/ rails      Option Kit
    500872-013          HDISK 1.0GB FastSCSI w/tray        Option Kit

    SOLUTION

    In order to properly remove termination from the Quantum 1080S drive, both
    the TE jumper at location J13 and the terminating resistors located next to
    the TE jumper must be removed from the drive. Documentation indicates that
    only jumper J13 needs to be removed in order to properly remove termination
    from the drive.