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    AST RESEARCH, INC.          TECHNICAL BULLETIN # 1179                4-5-95

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    INSTALLING A HARD DRIVE INTO THE MANHATTAN P-SERIES DRIVE TRAY

    PROBLEM

    The Manhattan P-series and the Manhattan XP expansion cabinet use a SCSI
    backplane which requires that hard drives be mounted in a special drive tray
    (AST part number 500922-0030).

    This Technical Bulletin documents the procedure and special considerations
    for installing a third-party SCSI drive into the drive tray.

    CAUSE

    The jumper settings and cable connections required for drive tray installation
    are not intuitive.  The AST SCSI Backplane Option Guide, AST part number
    003096-001, documents only part of this procedure.

    SYSTEMS AFFECTED
    AST PART NUMBER DESCRIPTION

    501502-XXX     AST Manhattan P-Series
    501516-001     AST Manhattan XP Expansion cabinet

    SOLUTION

    The following are the requirements to install a hard drive into the drive tray:

    1. The drive must not have termination enabled.

    2. The drive I.D. cable from the drive tray must be connected properly to the
    drive I.D. selection jumpers on the drive.

    To accomplish requirement (1), follow the instructions provided with the
    drive for disabling termination on the drive.  Usually this will involve
    either removing a set of resistor packs from the drive, or removing a
    "termination enable" jumper (typically labeled "TE").

    In order to accomplish requirement (2), the jumpers on the drive that control
    the SCSI ID selection must be identified.  Again, consult the instructions
    provided with the drive.

    Typically, the jumper pairs used to control the SCSI ID selection will be
    labeled "A0", "A1", and "A2".  The drive ID cable is the six-conductor cable,
    which runs from the backplane connector to the drive.
    It should be connected to the three jumper pairs that control the SCSI ID
    selection, with the end of the connector containing the red wire connected to
    the jumper corresponding to "A0."

    If the SCSI ID jumpers are not labeled "A0", "A1", and "A2", they can
    usually be identified by a chart in the drive documentation, which details all
    possible SCSI ID assignments, and the corresponding jumper settings.
    The jumper configuration for ID "1" will show only the "A0" jumper pair
    connected, while the configuration for ID "2" will show the "A1" pair
    connected, and the configuration for ID "4" will show only the "A2" pair
    connected.
    For example, the Seagate ST-15230N drive labels the jumpers "ID-1", "ID-
    2", and "ID-4",  which correspond to "A0", "A1", and "A2" -- On this drive,
    the drive ID cable should be installed on the "ID-1", "ID-2", and "ID-4"
    jumper pairs, with the red wire on the "ID-1" end.

    If there are multiple jumper sets which can be used to select the SCSI ID, all
    jumpers should be removed from any ID selection jumpers that are not
    connected to the drive ID cable.

    The remainder of the installation (power cable, 50-pin SCSI cable, and
    mounting screws) follows exactly as documented in the AST SCSI Backplane
    Option Guide (part number 003096-001).

    A newer revision of the AST SCSI Backplane Supplement (AST part number
    003281-001 A), due to be released in May, 1995, will contain more detail and
    illustrations about this process.