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    AST RESEARCH, INC.        TECHNICAL BULLETIN # 1078                 3-2-95

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    			 MANHATTAN P AND INCORRECT SCSI ID ASSIGNMENTS

    PROBLEM
    A SCSI disk drive displays an incorrect ID.  For example, a SCSI disk drive
    that is configured as ID #1 is seen by the computer system as ID #4.

    CAUSE
    The SCSI ID cable that connects between the SCSI disk drive and Mounting Tray
    Kit PCB is installed incorrectly.

    SYSTEMS AFFECTED
    AST PART NUMBER AND DESCRIPTION

    501502-XXX     Manhattan P5090                    All Models
    501503-XXX     Manhattan P5100                    All Models
    500889-XXX     Manhattan XP Expansion Chassis     All Models

    BACKGROUND
    In order for the hot-replacement and hot-standby features to function properly,
    all physical disk drives must be configured in a Mounting Tray Kit.
    Configuring the disk drive with the kit consists of:

    	1.  Securing the disk drive to the Mounting Tray chassis.
    	2.  Connecting the 50 pin SCSI signal cable to the disk drive.
    	3.  Connecting the power cable to the disk drive.
    	4.  Connecting the ID cable.

    One end of the ID cable connects to the SCSI ID address pins at the disk drive.
    Mating the cable properly consists of matching the red stripe on the cable to
    the Least Significant Bit of the ID address.  The other end of the ID cable
    connects to location J4 on the Mounting Tray's PCB.  Mating the cable properly
    consists of matching the red stripe on the cable to the Least Significant Bit
    of J4.  The Least Significant Bit at J4 is denoted by the numeral "1" on the
    silk-screen next to J4.

    SOLUTION
    Install the SCSI ID cable that connects between the SCSI disk drive and
    Mounting Tray Kit PCB correctly.  To do this, locate the end of the SCSI ID
    cable that connects to J4 of the Tray Kit PCB.  Unplug and rotate the end of
    the cable 180 degrees, then re-install it at J4.  After the cable has been
    rotated, the red stripe on the cable will be located at the Most Significant
    Bit of J4.

    Note: To date, AST has verified that the Quantum 1080s SCSI disk drive requires
    the SCSI ID cable to be configured so that the red stripe on the cable is
    installed mating with the Least Significant Bit of J4.  All other disk drives
    must be configured so that the red stripe on the cable is installed to mate
    with the Most Significant Bit of J4.